WO2012036265A1 - Porous silicon particles and complex porous silicon particles, and method for producing both - Google Patents

Porous silicon particles and complex porous silicon particles, and method for producing both Download PDF

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WO2012036265A1
WO2012036265A1 PCT/JP2011/071214 JP2011071214W WO2012036265A1 WO 2012036265 A1 WO2012036265 A1 WO 2012036265A1 JP 2011071214 W JP2011071214 W JP 2011071214W WO 2012036265 A1 WO2012036265 A1 WO 2012036265A1
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silicon
phase
particles
intermediate alloy
alloy
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PCT/JP2011/071214
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French (fr)
Japanese (ja)
Inventor
吉田　浩一
三好　一富
久留須　一彦
俊夫 谷
耕二 幡谷
西村　健
秀実 加藤
武 和田
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古河電気工業株式会社
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Priority claimed from JP2011195723A external-priority patent/JP5598861B2/en
Priority claimed from JP2011195751A external-priority patent/JP5877025B2/en
Application filed by 古河電気工業株式会社 filed Critical 古河電気工業株式会社
Priority to CN201180044169.1A priority Critical patent/CN103118976B/en
Priority to KR1020137006293A priority patent/KR101920942B1/en
Publication of WO2012036265A1 publication Critical patent/WO2012036265A1/en
Priority to US13/797,326 priority patent/US8980428B2/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to porous silicon particles and porous silicon composite particles used for negative electrodes for lithium ion batteries and the like.
  • lithium ion batteries using various carbon-based materials such as natural graphite, artificial graphite, amorphous carbon, and mesophase carbon, lithium titanate, tin alloys, and the like as a negative electrode active material have been put into practical use.
  • a negative electrode is formed by kneading a negative electrode active material, a conductive aid such as carbon black, and a resin binder to prepare a slurry, and applying and drying on a copper foil. Yes.
  • Patent Document 1 As a conventional method for manufacturing a negative electrode using silicon, a technique of using silicon as a negative electrode material for a lithium battery by mechanically pulverizing silicon into a size of several micrometers and applying a conductive material thereto (for example, Patent Document 1). Is known).
  • Patent Document 2 As a conventional manufacturing method of a negative electrode using silicon, a method of forming a groove such as a slit by anodizing a silicon substrate, a method of crystallizing fine silicon in a ribbon-like bulk metal (for example, , See Patent Document 2).
  • polymer particles such as polystyrene and PMMA are deposited on a conductive substrate, a metal alloying with lithium is plated thereon, and the polymer particles are removed by removing the polymer particles.
  • a technique for example, Patent Document 3 for producing a material is also known.
  • a technique for example, see Patent Documents 4 and 5 in which a material corresponding to a Si intermediate alloy which is an intermediate product of the present invention is used as a negative electrode material for a lithium battery is known.
  • a technique for example, see Patent Document 6) in which this is heat-treated and used as a negative electrode material for a lithium battery is known.
  • Patent Document 7 there is a technique (for example, refer to Patent Document 7) in which the element M is completely eluted and removed with an acid or alkali from a Si alloy of Si and the element M produced by applying the rapid solidification technique.
  • a technique for etching metallic silicon with hydrofluoric acid or nitric acid for example, Patent Documents 8 and 9 is also known.
  • Patent Document 1 is a single crystal having a size of several micrometers obtained by pulverizing single crystal silicon, and a plate or powder in which silicon atoms have a layered or three-dimensional network structure is used for the negative electrode. It is used as a substance.
  • silicon compounds silicon carbide, silicon cyanide, silicon nitride, silicon oxide, silicon boride, silicon borate, silicon boronitride, silicon oxynitride, silicon alkali metal
  • silicon compounds silicon carbide, silicon cyanide, silicon nitride, silicon oxide, silicon boride, silicon borate, silicon boronitride, silicon oxynitride, silicon alkali metal
  • silicon compounds silicon carbide, silicon cyanide, silicon nitride, silicon oxide, silicon boride, silicon borate, silicon boronitride, silicon oxynitride, silicon alkali metal
  • silicon compound group consisting of an alloy, a silicon alkaline earth metal alloy, and a silicon transition metal alloy.
  • the negative electrode active material described in Patent Document 1 is finely pulverized negative electrode active material, peeling of the negative electrode active material, generation of cracks in the negative electrode, A decrease in electrical conductivity between the active materials occurs and the capacity decreases. Therefore, there are problems that the cycle characteristics are poor and the life of the secondary battery is short.
  • silicon which is expected to be put to practical use as a negative electrode material, has a problem that cracking easily occurs and charge / discharge cycle characteristics are poor because the volume change during charge / discharge is large.
  • a negative electrode is formed by applying and drying a slurry of a negative electrode active material, a conductive additive and a binder.
  • the negative electrode active material and the current collector are bound with a binder of a resin having low conductivity, and the amount of resin used must be minimized so that the internal resistance does not increase.
  • Patent Document 3 polymer particles such as polystyrene and PMMA are deposited on a conductive substrate, a metal alloying with lithium is applied thereto by plating, and then the polymer particles are removed.
  • a metal porous body porous body
  • Si porous body there is a problem that it is extremely difficult to plate Si on polymer particles such as polystyrene and PMMA, which is not industrially applicable.
  • Patent Document 4 cools and solidifies the raw material melt constituting the alloy particles so that the solidification rate is 100 ° C./second or more, and at least partially surrounds the Si phase grains.
  • Forming a negative electrode material for a non-aqueous electrolyte secondary battery comprising: forming an alloy containing a Si-containing solid solution or an intermetallic compound phase.
  • Li reacts
  • it is necessary to diffuse and move through the included Si-containing solid solution the reactivity is poor, and further, the practical application from the point that the content of Si that can contribute to charge and discharge is small. Has not reached.
  • Patent Document 5 discloses silicon containing silicon (the silicon content is 22% by mass or more and 60% by mass or less) and one or more metal elements of copper, nickel, and cobalt. It is composed of alloy powder. By synthesizing this by a single roll method or an atomizing method, pulverization based on volume change due to occlusion / release of lithium ions or the like is suppressed.
  • this method when Li reacts, it is necessary to diffuse and move through the included Si-containing solid solution, the reactivity is poor, and further, the practical application from the point that the content of Si that can contribute to charge and discharge is small. Has not reached.
  • Patent Document 6 is selected from Si, Co, Ni, Ag, Sn, Al, Fe, Zr, Cr, Cu, P, Bi, V, Mn, Nb, Mo, In, and rare earth elements. It includes a step of rapidly cooling a molten alloy containing one or more elements and obtaining a Si-based amorphous alloy and a step of heat-treating the obtained Si-based amorphous alloy. By heat-treating the Si-based amorphous alloy, fine crystalline Si nuclei of about several tens of nm to 300 nm are precipitated.
  • this method when Li reacts, it is necessary to diffuse and move through the included Si-containing solid solution, the reactivity is poor, and further, the practical application from the point that the content of Si that can contribute to charge and discharge is small. Has not reached.
  • Patent Document 7 is applied when producing an amorphous ribbon or fine powder, and solidifies at a cooling rate of 10 4 K / second or more.
  • a cooling rate 10 4 K / second or more.
  • a special alloy system Cu-Mg system, Ni-Ti system, etc.
  • Cu-Mg system, Ni-Ti system, etc. can form an amorphous metal at 10 4 K / second or more, but other systems (eg, Si-Ni system) have a cooling rate. Even when solidified at 10 4 K / second or more, an amorphous metal cannot be obtained, and a crystalline phase is formed.
  • the size of the crystal when this crystal phase is formed follows the relationship between the cooling rate (R: K / sec) and the dendrite arm spacing (DAS: ⁇ m).
  • DAS A ⁇ R B (generally A: 40 to 100, B: ⁇ 0.3 to ⁇ 0.4) Therefore, in the case of having a crystal phase, for example, when A: 60 and B: ⁇ 0.35, DAS becomes 1 ⁇ m at R: 10 4 K / sec.
  • the crystal phase conforms to this size, and a fine crystal phase such as 10 nm cannot be obtained. For these reasons, it is not possible to obtain a porous material composed of a fine crystal phase with this rapid solidification technique alone with materials such as Si—Ni.
  • metal silicon is etched using hydrofluoric acid or nitric acid to create fine holes on the surface.
  • the BET specific surface area is 140 to 400 m 2 / g, which is insufficient as an active material for Si negative electrode from the viewpoint of charge / discharge response.
  • vacancies formed by etching tend to be harder to form as the inside of the particles.
  • vacancies do not exist uniformly from the particle surface to the center, and coarse silicon grains are formed near the particle center. The Therefore, with the volume expansion and contraction during charging / discharging, there is a problem that pulverization progresses inside the particles and the life is short.
  • the present invention has been made in view of the above-described problems, and its object is to provide porous silicon particles and porous materials suitable for a negative electrode material for a lithium ion battery that realizes high capacity and good cycle characteristics. It is to obtain a porous silicon composite particle.
  • the present inventor has found that a fine porous material is formed by spinodal decomposition of silicon alloy (precipitation of silicon in the molten metal from the silicon alloy) and dealloying (dealloying). It has been found that silicon can be obtained. Since silicon is precipitated in the molten metal from the silicon alloy in a high-temperature molten metal, the primary particle diameter and porosity are large in the surface layer portion and the inside of the porous silicon particles obtained by dealloying (dealloying). Distribution is unlikely to occur.
  • the concentration inside the particle is restricted in the diffusion of decomponent elements, so the porosity of the particle surface layer portion increases and the porosity inside the particle decreases.
  • a Si core having no pores remains in the center of the particle, and the coarse Si in the center is pulverized during the reaction with Li, resulting in poor cycle characteristics.
  • the present invention has been made based on this finding.
  • Porous silicon particles formed by bonding a plurality of silicon fine particles, wherein the porous silicon particles have an average particle size of 0.1 ⁇ m to 1000 ⁇ m, and the porous silicon particles have a tertiary structure having continuous voids.
  • the porous silicon particles have an original network structure, the average porosity of the porous silicon particles is 15 to 93%, the porosity Xs of the surface vicinity region of 50% or more in the radial direction, and the particle internal region of 50% or less in the radial direction
  • the silicon fine particles have an average particle diameter or average column diameter of 2 nm to 2 ⁇ m, and an average particle diameter Ds of the silicon fine particles in the surface vicinity region of 50% or more in the radial direction is within 50% in the radial direction.
  • the ratio Ds / Di which is the ratio of the average particle diameter Di of the silicon fine particles in the particle internal region, is 0.5 to 1.5, and the silicon fine particles contain 80 atomic% or more of silicon in the ratio of elements excluding oxygen.
  • the porous silicon particle according to (1) which is a solid silicon fine particle characterized by the above.
  • Porous silicon composite particles formed by joining a plurality of silicon fine particles and a plurality of silicon compound particles, wherein the silicon compound particles are silicon, As, Ba, Ca, Ce, Co, Cr, Cu , Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti , Tm, U, V, W, Y, Yb, Zr, and a compound with one or more composite elements selected from the group consisting of Tm, U, V, W, Y, Yb, Zr, and the average particle size of the porous silicon composite particles is 0.1 ⁇ m
  • the silicon fine particles have an average particle diameter or average column diameter of 2 nm to 2 ⁇ m, and the silicon fine particles are solid silicon fine particles containing 80 atomic% or more of silicon in a ratio of elements excluding oxygen.
  • the porous silicon composite particles according to (4) characterized in that (6) Solid silicon, wherein the silicon compound particles have an average particle diameter of 50 nm to 50 ⁇ m, and the silicon compound particles contain 50 to 90 atomic% of silicon in a ratio of elements excluding oxygen.
  • the porous silicon composite particles according to (4), wherein the porous silicon composite particles are compound particles.
  • the average particle diameter Ds of the silicon fine particles in the surface vicinity region of 50% or more in the radial direction of the porous silicon composite particles, and the particle internal region of 50% or less in the radial direction of the porous silicon composite particles The porous silicon composite particles according to (4), wherein Ds / Di, which is the ratio of the average particle diameter Di of the silicon fine particles, is 0.5 to 1.5.
  • Step (9) It is an alloy of silicon and one or more intermediate alloy elements described in Table 1, and the ratio of silicon is 10 atomic% or more of the whole.
  • the silicon intermediate alloy has a ribbon shape, a foil piece shape or a linear shape with a thickness of 0.1 ⁇ m to 2 mm, or a granular shape or a lump shape with a particle size of 10 ⁇ m to 50 mm.
  • the second phase is dissolved and removed with at least one of an acid, an alkali, and an organic solvent, or only the second phase is evaporated by heating and decompressing.
  • the step (a) is a step of producing a powdery silicon intermediate alloy by using a gas atomization method or a rotating disk atomization method with a molten metal of the silicon and the intermediate alloy element (9) ) For producing porous silicon particles.
  • the step (a) includes a step of cooling the molten metal of silicon and the intermediate alloy element in a mold to produce a lump silicon intermediate alloy, according to (9) A method for producing porous silicon particles.
  • Silicon is blended with Cu so that the ratio of silicon is 10 to 30 atomic% of the total, and the ribbon shape, foil piece shape, linear shape with a thickness of 0.1 ⁇ m to 2 mm, or the particle size of 10 ⁇ m to 50 mm
  • a method for producing porous silicon particles wherein the phase is composed of an alloy of the Cu and the molten element and / or the molten element substituted for the Cu.
  • Silicon is mixed with Mg so that the ratio of silicon is 10 to 50 atomic%, and the thickness is 0.1 ⁇ m to 2 mm in ribbon shape, foil piece shape, linear shape, or particle size of 10 ⁇ m to 50 mm.
  • the step (a) for producing a granular / lumped silicon intermediate alloy, and the silicon alloy is selected from the group consisting of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, Tl, and Zn.
  • Ni is blended with Ni so that the silicon content is 10 to 55 atomic% of the total, and ribbons, foil pieces, and wires with a thickness of 0.1 ⁇ m to 2 mm, or a particle size of 10 ⁇ m to 50 mm
  • a method for producing porous silicon particles characterized in that a phase is composed of an alloy of Ni and the molten element and / or the molten element substituted for Ni.
  • Silicon is mixed with Ti so that the silicon ratio is 10 to 82 atomic% of the whole, and the thickness is 0.1 ⁇ m to 2 mm in ribbon shape, foil piece shape, linear shape, or particle size of 10 ⁇ m to 50 mm.
  • the step (a) for producing a granular / lumped silicon intermediate alloy and the silicon alloy is selected from the group consisting of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Zn
  • One or more complex elements listed in Table 2 corresponding to the alloy elements are immersed in an alloy bath containing 10 atomic% or less and a total of 20 atomic% or less, and silicon fine particles, silicon compound particles of silicon and complex elements,
  • the silicon intermediate alloy is in the form of a ribbon, foil or wire having a thickness of 0.1 ⁇ m to 2 mm, or in the form of a powder, granule or block having a particle size of 10 ⁇ m to 50 mm.
  • the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is heated and reduced in pressure.
  • the method for producing porous silicon composite particles according to (19), comprising a step of removing by evaporation.
  • the step (a) is a step of producing a ribbon-like or thin-plate-like silicon intermediate alloy by using a single-roll casting machine or a twin-roll casting machine from the molten silicon, the intermediate alloy element, and the composite element.
  • the step (a) is a step of producing a powdery silicon intermediate alloy by using an atomizing method of the molten silicon, the intermediate alloy element, and the composite element (19). ) For producing porous silicon composite particles.
  • the step (a) includes a step of cooling a molten metal of the silicon, the intermediate alloy element, and the composite element in a mold to produce a lump silicon intermediate alloy ( The method for producing porous silicon composite particles according to 19).
  • the ratio of silicon to Cu is 10 to 30 atom% (X atom%) with respect to the whole, and As, Ba, Ca, Ce, Co, Cr, Er, Fe, Gd, Hf , Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb , One or more complex elements (Z 1 , Z 2 , Z 3 ,...
  • Atomic%) selected from the group consisting of Zr so as to satisfy the formulas (1) and (2) of (20)
  • the intermediate alloy is made of at least one solution selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, and Zn.
  • step (C) wherein the second phase is composed of an alloy of the Cu and the molten metal element and / or the molten metal element, and the step (c) includes the second phase as an acid, an alkali, Porous silicon composite particles characterized by comprising a step of dissolving and removing with at least one organic solvent, or a step of evaporating and removing only the second phase by heating and depressurizing Manufacturing method.
  • Cu (Y atom%) is mixed with silicon in a proportion of 10 to 30 atom% (X atom%), with a thickness of 0.1 ⁇ m to 2 mm in ribbon, foil, or wire
  • a step (a) of producing a granular / lumped silicon intermediate alloy having a particle size of 10 ⁇ m to 50 mm and the silicon intermediate alloy is selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, Zn As a main component of the molten metal having one or more molten elements, As, Ba, Ca, Ce, Co, Cr, Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu , Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr, each of one or more complex elements Soaked in an alloy bath prepared by adding 10 atomic percent or less and a total of 20
  • the second phase is composed of an alloy of the Cu and the molten element and / or the molten element, and the step (c) includes at least one of the acid, alkali, and organic solvent in the second phase.
  • a method for producing porous silicon composite particles comprising a step of dissolving and removing, or a step of evaporating and removing only the second phase by heating and decompressing.
  • Atomic%) selected from the group consisting of Zr so as to satisfy the formulas (1) and (2) of (20)
  • the intermediate alloy is made of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, Tl, Zn.
  • Mg (Y atom%) is mixed with 10 to 50 atom% (X atom%) of silicon, and ribbons, foil pieces, and lines with a thickness of 0.1 ⁇ m to 2 mm
  • a step (a) for producing a granular / lumped silicon intermediate alloy having a particle size of 10 ⁇ m to 50 mm and the silicon intermediate alloy is made of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, As a main component of one or more molten metal elements selected from the group consisting of Tl and Zn, As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Ni , Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr.
  • the second phase is composed of an alloy of the Mg and the molten metal element and / or the molten metal element, and the step (c) includes the second phase of an acid, an alkali, or an organic solvent.
  • a method for producing porous silicon composite particles comprising: a step of dissolving and removing at least one or more, or a step of evaporating and removing only the second phase by heating and depressurizing. .
  • Ni (Y atom%) is 10 to 55 atom% (Y atom%) relative to the whole, and As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf , Mn, Mo, Nb, Nd, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr
  • Atomic%) are blended so as to satisfy the formulas (1) and (2) of (20) (A) forming a ribbon-like, foil-like, linear or powdery / granular / lumped silicon intermediate alloy having a thickness of 0.1 ⁇ m to 2 mm, and the silicon intermediate alloy One or more molten elements selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, Zn A step (b) of immersing the substrate in a molten metal containing as a main component to separate silicon fine particles, silicon and silicon compound particles of the complex element, and a second phase; and removing the second phase (c) And the second phase is composed of the alloy of Ni and the molten metal element and / or the molten metal element, and the step (c) includes the second phase as an acid, an alkali, and an organic solvent.
  • Method. (32) Ni (Y atom%) is mixed with 10 to 55 atom% (Y atom%) of silicon in the whole, and ribbons, foil pieces, and lines with a thickness of 0.1 ⁇ m to 2 mm Or a step (a) of producing a granular / lumped silicon intermediate alloy having a particle size of 10 ⁇ m to 50 mm, and the silicon intermediate alloy is selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, Zn As a main component of the molten metal containing one or more molten elements, As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Os, Pr, Pt, Pu, Re 10 atoms each of one or more complex elements selected from the group consisting of Rh, Ru, Sc, S
  • step (c) comprises dissolving the second phase with at least one of an acid, an alkali, and an organic solvent.
  • a method for producing porous silicon composite particles comprising a step of removing, or a step of evaporating and removing only the second phase by heating and decompressing.
  • the proportion of silicon in Ti is 10 to 80 atom% (Y atom%) with respect to the whole, and As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf , Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Tm, U, V, W, Y , Yb, Zr selected from the group consisting of one or more complex elements (Z 1 , Z 2 , Z 3 ,...
  • the silicon intermediate alloy is made of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, or Zn.
  • a method for producing porous silicon composite particles characterized by the above.
  • Ti (Y atom%) is mixed with 10 to 80 atom% (Y atom%) of silicon, and ribbons, foil pieces, and wires with a thickness of 0.1 ⁇ m to 2 mm
  • porous silicon particles and porous silicon composite particles suitable for a negative electrode material for a lithium ion battery that realizes a high capacity and good cycle characteristics.
  • FIG. 1 The figure which shows the porous silicon particle 1 concerning this invention
  • FIG. (b) The figure which shows the surface vicinity area
  • FIG. (A)-(c) The figure which shows the outline of the manufacturing method of the porous silicon particle 1.
  • FIG. The figure explaining the manufacturing process of the ribbon-shaped silicon intermediate alloy which concerns on this invention. The figure explaining the immersion process to the molten metal element of the ribbon-shaped silicon intermediate alloy which concerns on this invention.
  • A) The figure which shows the gas atomizer 31 which concerns on this invention,
  • (b) The figure which shows the rotary disk atomizer 41 concerning this invention.
  • (A)-(c) The figure explaining the manufacturing process of a lump silicon intermediate alloy.
  • FIG. 5A to 5C are diagrams showing an outline of a first method for producing porous silicon composite particles 101.
  • FIGS. (A)-(c) The figure which shows the outline of the 2nd manufacturing method of the porous silicon composite particle 101.
  • FIG. 4 is an SEM photograph of the surface of porous silicon particles according to Example 1-12. 4 is an SEM photograph of porous silicon particles according to Comparative Example 1-1.
  • Example 2 is an X-ray diffraction grating image of porous silicon particles according to Example 1-12.
  • 4 is a SEM photograph of the surface of porous silicon composite particles according to Example 2-1. 4 is an SEM photograph of a cross section inside the porous silicon composite particles according to Example 2-1. 4 is a SEM photograph of the surface of porous silicon composite particles according to Example 2-1.
  • X-ray diffraction grating image of silicon fine particles of porous silicon composite particles according to Example 2-1. 4 is a TEM photograph and a limited-field electron diffraction image (upper left) of silicon fine particles of porous silicon composite particles according to Example 2-1.
  • porous silicon particles (Configuration of porous silicon particles) A porous silicon particle 1 according to the present invention will be described with reference to FIG.
  • the porous silicon particle 1 is a porous body having a three-dimensional network structure having continuous voids, which is formed by bonding silicon fine particles 3, having an average particle size of 0.1 ⁇ m to 1000 ⁇ m, and an average porosity of 15 to 93. %.
  • the porous silicon particles 1 contain 80 atomic% or more of silicon in the ratio of elements excluding oxygen, and the rest are solid particles containing intermediate alloy elements, molten metal elements, and other inevitable impurities described later. It is characterized by being.
  • the oxide layer (oxide film) on the surface of the silicon fine particles can be formed by immersing in 0.0001 to 0.1 N nitric acid after removing the second phase with hydrochloric acid or the like. Alternatively, it can also be formed by removing the second phase by distillation under reduced pressure and holding it under an oxygen partial pressure of 0.00000001 to 0.02 MPa.
  • the porous silicon particles 1 are divided into a surface vicinity region S of 50% or more in the radial direction and a particle inner region I of 50% or less in the radial direction.
  • Ds average particle size of the silicon fine particles constituting the region near the surface of the particle
  • Di average particle size of the silicon fine particles constituting the particle internal region of the porous silicon particle
  • the ratio Xs / Xi which is the ratio of the porosity Xs of the near-surface region S and the porosity Xi of the particle internal region I, is 0.5 to 1.5. That is, the porous silicon particles according to the present invention have the same pore structure in the region near the surface and the region inside the particle, and the entire particle has a substantially uniform pore structure.
  • the silicon fine particles 3 constituting the porous silicon particles 1 are single crystals having an average particle diameter or average column diameter of 2 nm to 2 ⁇ m and having a crystallinity, and a solid containing 80 atomic% or more of silicon in a ratio of elements excluding oxygen. It is a characteristic particle.
  • the particle diameter can be measured if substantially spherical fine particles exist independently, but when a plurality of fine particles are joined to form a substantially columnar shape, a cross section perpendicular to the long axis.
  • the average strut diameter corresponding to the column diameter is used for evaluation.
  • the three-dimensional network structure in the present invention means a structure in which pores are connected to each other, such as a co-continuous structure or a sponge structure generated in the spinodal decomposition process.
  • the pores of the porous silicon particles have a pore diameter of about 0.1 to 300 nm.
  • the average particle diameter or the average column diameter of the silicon fine particles 3 is 2 nm to 2 ⁇ m, preferably 10 to 500 nm, more preferably 15 to 100 nm.
  • the average porosity of the porous silicon particles 1 is 15 to 93%, preferably 30 to 80%, more preferably 40 to 70%.
  • the silicon fine particles 3 are locally bonded to each other, and the area of the bonded portion of the silicon fine particles 3 is 30% or less of the surface area of the silicon fine particles. That is, the surface area of the porous silicon particles 1 is 70% or more as compared with the surface area obtained on the assumption that the silicon fine particles 3 exist independently.
  • the porous silicon particles according to the present invention are usually present in an aggregated state.
  • the particle diameter is measured by using image information of an electron microscope (SEM) and a volume-based median diameter of a dynamic light scattering photometer (DLS).
  • SEM electron microscope
  • DLS dynamic light scattering photometer
  • the particle shape is confirmed in advance using an SEM image
  • the particle size is obtained using image analysis software (for example, “A Image-kun” (registered trademark) manufactured by Asahi Kasei Engineering), or DLS ( For example, it can be measured by DLS-8000 manufactured by Otsuka Electronics Co., Ltd. If the particles are sufficiently dispersed and not agglomerated at the time of DLS measurement, almost the same measurement results can be obtained with SEM and DLS.
  • the average particle diameter is obtained mainly using a surface scanning electron microscope or a transmission electron microscope.
  • the average column diameter is defined as the column diameter of rod-shaped (columnar) silicon particles having an aspect ratio of 5 or more. Let the average value of this support
  • the average porosity means the ratio of voids in the particles.
  • Submicron pores can be measured by nitrogen gas adsorption, but when the pore size is wide, observation with an electron microscope or mercury intrusion method (JIS R 1655 “fine mercury intrusion method of fine ceramics” Method of measuring the pore size distribution of compacts by using “Derived from the relationship between pressure and mercury volume when mercury enters the voids", Gas adsorption method (JIS Z 8830: 2001) Specific surface area of powder (solid) by gas adsorption Measurement is possible by measuring method).
  • the porous silicon particles 1 according to the present invention have an average particle diameter of 0.1 ⁇ m to 1000 ⁇ m depending on the Si concentration of the Si intermediate alloy and the cooling rate at the time of manufacturing the intermediate alloy. Note that the particle size is reduced by decreasing the Si concentration or increasing the cooling rate.
  • the average particle diameter is preferably 0.1 to 50 ⁇ m, more preferably 1 to 30 ⁇ m, and further preferably 5 to 20 ⁇ m. Therefore, when the porous silicon particles are small, they are used as aggregates or granulated bodies. Further, when the porous silicon particles are large, there is no problem even if the porous silicon particles are roughly pulverized and used.
  • FIG. 2A silicon and an intermediate alloy element are heated and melted to produce a silicon intermediate alloy 7. Thereafter, the silicon intermediate alloy 7 is immersed in a molten metal element shown in Table 1. At this time, as shown in FIG. 2B, the intermediate alloy element of the silicon intermediate alloy 7 is eluted into the molten metal to form the second phase 9 mainly composed of the molten element, and only silicon is silicon. Precipitate or crystallize as fine particles 3.
  • the second phase 9 is an alloy of an intermediate alloy element and a molten element, or is composed of a molten element substituted for the intermediate alloy element.
  • silicon fine particles 3 are bonded to each other to form a three-dimensional network structure. Thereafter, as shown in FIG. 2C, when the second phase is removed by a method such as decomponent corrosion using acid or alkali, porous silicon particles 1 to which silicon fine particles 3 are bonded are obtained.
  • this silicon intermediate alloy is immersed in a molten element (Y) bath specified in Table 1, the molten element (Y) penetrates while diffusing into the silicon intermediate alloy, and the intermediate alloy element ( X) forms a molten element (Y) and an alloy layer as a second phase.
  • the intermediate alloy element (X) in the alloy is eluted in the metal bath of the molten element (Y), and the molten element (Y) forms a new second phase.
  • silicon atoms contained in the silicon intermediate alloy are left behind.
  • a network of silicon atoms is formed, and a three-dimensional network structure is formed.
  • the silicon primary crystal which is not an alloy in the intermediate alloy is not related to the precipitation of silicon fine particles in the dipping process and is not related to the removal of the second phase such as decomponent corrosion, and remains as the silicon primary crystal. Therefore, silicon once crystallized is coarse and does not form a three-dimensional network structure. Therefore, in the step of forming the silicon intermediate alloy, it is preferable that no silicon crystal is generated in the silicon alloy.
  • Condition 1 The melting point of the molten element (Y) is lower than the melting point of silicon by 50K or more. If the melting point of the molten element (Y) is close to the melting point of silicon, condition 1 is necessary because silicon is dissolved in the molten metal when the silicon alloy is immersed in the molten molten element.
  • Condition 2 Si primary crystals do not occur when silicon and intermediate alloy elements are solidified. When an alloy of silicon and intermediate alloy element (X) is formed, a coarse silicon primary crystal is formed when the hypereutectic region is reached when the silicon concentration increases.
  • This silicon crystal does not cause diffusion or re-aggregation of silicon atoms during the dipping process, and does not form a three-dimensional network structure.
  • Condition 3 The solubility of silicon in the molten metal element is lower than 5 atomic%. This is because when the intermediate alloy element (X) and the molten metal element (Y) form the second phase, it is necessary to prevent silicon from being included in the second phase.
  • Condition 4 The intermediate alloy element and the molten metal element do not separate into two phases. When the intermediate alloy element (X) and the molten metal element (Y) are separated into two phases, the intermediate alloy element is not separated from the silicon alloy, and the silicon atoms do not diffuse and reaggregate. Furthermore, even if the treatment with an acid is performed, the intermediate alloy element remains in the silicon particles.
  • the combinations of the intermediate alloy element and the molten metal element that can be used for producing the porous silicon particles are as follows. Moreover, the ratio of silicon is 10 atomic% or more of the whole, and is below the highest value among the maximum Si contents in Table 1 below corresponding to the intermediate alloy elements.
  • the Si content is 10 to 30 atomic% with respect to the sum of Si and the intermediate alloy element, and the average porosity of the obtained porous silicon particles is 47 to 85%. is there.
  • the Si content is 10 to 50 atomic% with respect to the sum of Si and the intermediate alloy element, and the average porosity of the obtained porous silicon particles is 42 to 92%. is there.
  • the Si content is 10 to 55 atomic% with respect to the sum of Si and the intermediate alloy element, and the average porosity of the obtained porous silicon particles is 15 to 85%. is there.
  • the Si content is 10 to 82 atomic% with respect to the sum of Si and the intermediate alloy element, and the average porosity of the obtained porous silicon particles is 15 to 89%. is there.
  • the intermediate alloy element two or more of the listed elements can be used as the intermediate alloy element.
  • the molten element corresponding to any of these intermediate alloy elements is used as the molten element.
  • the molten silicon alloy 13 is dropped from the crucible 15 using, for example, continuous thin plate casting in a twin roll casting machine or a single roll casting machine 11 as shown in FIG.
  • a solid or ribbon-like silicon intermediate alloy 19 is produced by solidifying the steel roll 17 while being in contact therewith.
  • the linear mother alloy may be manufactured by a direct spinning method.
  • the silicon intermediate alloy may be in the form of a foil piece having a certain length, unlike a linear shape or a ribbon shape.
  • the thickness of the linear or ribbon-like silicon intermediate alloy 19 is preferably 0.1 ⁇ m to 2 mm, more preferably 0.1 to 500 ⁇ m, and further preferably 0.1 to 50 ⁇ m.
  • the cooling rate during solidification of the silicon intermediate alloy is 0.1 K / s or more, preferably 100 K / s or more, more preferably 400 K / s or more. This contributes to shortening the heat treatment time in the next step by reducing the grain size of the primary crystal formed in the initial stage of solidification. Further, the particle diameter of the porous silicon particles is reduced proportionally by reducing the particle diameter of the primary crystal. If the thickness of the silicon alloy (intermediate alloy) is 2 mm or more, it is not preferable because the Si content is high and the toughness is poor and cracks and disconnections occur.
  • the silicon intermediate alloy was selected from Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Tl, Zn listed in Table 1 corresponding to the intermediate alloy element used.
  • the ribbon-shaped silicon intermediate alloy 19 is sent in the direction of the arrow in the drawing and dipped in the molten metal 23 of the molten element. Thereafter, the film is wound up via the sink roll 25 and the support roll 27.
  • the molten metal 23 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more. Although immersion in the molten metal 23 depends on the molten metal temperature, it is preferably 5 seconds or more and 10,000 seconds or less. This is because coarse Si grains are produced when the immersion is performed for 10,000 seconds or more. Then, it is cooled in a non-oxidizing atmosphere. As described later, it is preferable that oxygen is not contained in the molten metal 23.
  • the second phase which is an alloy of the intermediate alloy element and the molten metal element or the second phase composed of the molten metal element replaced with the intermediate alloy element is dissolved and removed with at least one of an acid, an alkali and an organic solvent.
  • the step or the second phase is heated and decompressed to remove only the second phase by evaporation. By removing the second phase, porous silicon particles are obtained.
  • the acid may be any acid that dissolves the intermediate alloy element and the molten metal element and does not dissolve silicon, and examples thereof include nitric acid, hydrochloric acid, and sulfuric acid.
  • the particle diameter becomes 0.1 ⁇ m to 1000 ⁇ m. Note that the particle size is reduced by lowering the silicon concentration or increasing the cooling rate.
  • the average particle diameter is preferably 0.1 to 50 ⁇ m, more preferably 1 to 30 ⁇ m, and further preferably 5 to 20 ⁇ m.
  • porous silicon particles when the porous silicon particles are small, an aggregate or a granulated body is prepared using a conductive binder, and is used after being formed into a slurry and applied to a current collector. Further, when the porous silicon particles are large, there is no problem even if the porous silicon particles are roughly pulverized with a mortar or the like. Since the fine particles are locally joined, they can be easily crushed.
  • a powdery, granular, or massive silicon intermediate alloy may be used in place of the linear or ribbon-like silicon intermediate alloy 19.
  • Table 1 As, Ba, Ca, Ce, Co, Cr, Cu, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, P, Pd, One or more selected from the group consisting of Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr A mixture in which the intermediate alloy element is blended so that the ratio of silicon is 10 to 98 atomic%, preferably 15 to 50 atomic%, is heated and melted in a vacuum furnace or a non-oxidizing atmosphere furnace. Thereafter, a method of producing a grain / powder silicon intermediate alloy by the atomizing method as shown in FIG. 5
  • FIG. 5 (a) shows a gas atomizing apparatus 31 capable of producing a powdered silicon intermediate alloy 39 by a gas atomizing method.
  • the crucible 33 there is silicon melted by induction heating or the like and a silicon alloy 13 of an intermediate alloy element.
  • the silicon alloy is dropped from the nozzle 35 and at the same time, a jet stream 38 of inert gas from the gas injector 37 is blown. Then, the molten metal of the silicon alloy 13 is pulverized and solidified as droplets to form a powdery silicon intermediate alloy 39.
  • FIG. 5B shows a rotating disk atomizing device 41 that can manufacture the powdered silicon intermediate alloy 51 by the rotating disk atomizing method.
  • the crucible 43 In the crucible 43, there is dissolved silicon and the silicon alloy 13 of the intermediate alloy element. This silicon alloy is dropped from the nozzle 45, and the molten metal of the silicon alloy 13 is dropped on the rotating disk 49 that rotates at high speed, thereby tangentially.
  • a powdery silicon intermediate alloy 51 is formed by applying a shearing force in the direction and crushing.
  • FIG. 6 is a diagram illustrating a process of forming the massive silicon intermediate alloy 57 by the ingot manufacturing method.
  • the molten silicon alloy 13 is put into the mold 55 from the crucible 53. Thereafter, the silicon alloy 13 is cooled in the mold 55 and solidified, and then the mold 55 is removed to obtain a bulk silicon intermediate alloy 57. If necessary, the bulk silicon intermediate alloy 57 is crushed to obtain a granular silicon intermediate alloy.
  • the thickness of the granular silicon intermediate alloy is preferably 10 ⁇ m to 50 mm, more preferably 0.1 to 10 mm, and further preferably 1 to 5 mm.
  • the cooling rate during solidification of the silicon alloy is 0.1 K / s or more. If the thickness of the silicon intermediate alloy is increased to 50 mm or more, the heat treatment time becomes longer, which is not preferable because the particle diameter of the porous silicon particles grows and becomes coarse. In that case, this silicon intermediate alloy can be dealt with by mechanically grinding it to 50 mm or less.
  • the silicon intermediate alloy was selected from Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Tl, Zn listed in Table 1 corresponding to the intermediate alloy element used. It is immersed in the molten metal element to form a spinodal decomposition of silicon and a second phase which is an alloy of the intermediate alloy element and the molten element element.
  • the oxygen in the molten metal is desirably reduced in advance to 100 ppm or less, preferably 10 ppm or less, more preferably 2 ppm or less. This is because dissolved oxygen in the molten metal reacts with silicon to form silica, and with this as a nucleus, silicon grows in a facet shape and becomes coarse.
  • a countermeasure it can be reduced by a solid reducing material such as charcoal / graphite or a non-oxidizing gas, or an element having a strong affinity for oxygen may be added in advance. Silicon particles are formed for the first time in this dipping process.
  • a solid reducing material such as charcoal / graphite or a non-oxidizing gas, or an element having a strong affinity for oxygen may be added in advance. Silicon particles are formed for the first time in this dipping process.
  • a molten silicon immersion device 61 as shown in FIG. 7A is used, and the granular silicon intermediate alloy 63 is placed in a dipping bowl 65 and dipped in a molten metal 69 of a molten element.
  • the pressing cylinder 67 is moved up and down to give mechanical vibration to the silicon intermediate alloy or molten metal, or to give vibration by ultrasonic waves, as shown in FIG.
  • the reaction can be advanced in a short time by stirring the molten metal using mechanical stirring using the mechanical stirrer 81 and gas injection using the gas blowing plug 83 or electromagnetic force. Then, it is pulled up in a non-oxidizing atmosphere and cooled.
  • the molten metal 69 or 79 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more.
  • the immersion in the molten metal depends on the molten metal temperature, but is preferably 5 seconds or longer and 10,000 seconds or shorter. This is because coarse Si grains are produced when immersion is performed for 10,000 seconds or more.
  • porous silicon particles having an unprecedented three-dimensional network structure can be obtained.
  • porous silicon particles having a substantially uniform pore structure can be obtained. This is because precipitation of silicon fine particles from the silicon intermediate alloy in the molten metal is performed in the molten metal at a high temperature, so that the molten metal penetrates into the particles.
  • porous silicon particles according to the present invention are used as a negative electrode active material of a lithium ion battery, a high capacity and long life negative electrode can be obtained.
  • porous silicon composite particles (Configuration of porous silicon composite particles)
  • the porous silicon composite particles according to the present invention will be described with reference to FIG.
  • the porous silicon composite particles 101 according to the present invention are formed by bonding silicon fine particles 103 and silicon compound particles 105, and the average particle size of the porous silicon composite particles 101 is zero.
  • the average porosity of the porous silicon composite particles 101 is 15 to 93% and has a three-dimensional network structure composed of continuous voids.
  • the three-dimensional network structure in the present invention means a structure in which pores are connected to each other, such as a co-continuous structure or a sponge structure generated in the spinodal decomposition process.
  • the pores of the porous silicon composite particles have a pore diameter of about 0.1 to 300 nm.
  • Xs / Xi which is the ratio of the porosity Xs of the surface vicinity region of 50% or more in the radial direction and the porosity Xi of the particle internal region within 50% in the radial direction, is 0.00. 5 to 1.5. That is, the porous silicon composite particles according to the present invention have the same pore structure in the surface vicinity region and the particle inner region, and the whole particle has a substantially uniform pore structure.
  • the porosity Xs can be obtained by SEM observation of the surface of the porous silicon composite particle 101, and the porosity Xi is obtained by observing a portion corresponding to the particle internal region in the cross section of the porous silicon composite particle 101 by SEM. Can be obtained.
  • the silicon fine particles 103 have an average particle diameter or average column diameter of 2 nm to 2 ⁇ m, preferably 10 to 500 nm, and more preferably 20 to 300 nm.
  • the average porosity is 15 to 93%, preferably 50 to 80%, more preferably 60 to 70%.
  • the crystal structure of each silicon fine particle 103 is a single crystal having crystallinity.
  • the silicon fine particles 103 contain 80 atomic% or more of silicon in a ratio of elements excluding oxygen, and the remainder are solid fine particles containing an intermediate alloy element, a molten metal element, and other inevitable impurities described later.
  • the porous silicon composite particles 101 are divided into a surface vicinity region S of 50% or more in the radial direction and a particle inner region I of 50% or less in the radial direction.
  • Ds / Di where Ds is the average particle size of the silicon fine particles constituting the surface vicinity region of the porous silicon composite particles, and Di is the average particle size of the silicon fine particles constituting the particle inner region of the porous silicon composite particles Is 0.5 to 1.5.
  • the average particle diameter Ds can be obtained by observing the surface of the porous silicon composite particle 1 with an SEM, and the average particle diameter Di is obtained by SEM of a cross section of a portion corresponding to the particle internal region of the porous silicon composite particle 1. It can be obtained by observation.
  • the silicon compound particles 105 have an average particle size of 50 nm to 50 ⁇ m, preferably 100 nm to 20 ⁇ m, and more preferably 200 nm to 10 ⁇ m.
  • As Ba, Ca, Ce, Co, Cr, Cu, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu
  • One or more complex elements selected from the group consisting of: Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr; It is a particle having solid crystallinity composed of 50 to 75 atomic% of silicon and an intermediate alloy element, a molten metal element, and other inevitable impurities described later.
  • the silicon compound particles 105 are larger than the silicon fine particles 103.
  • the surface of the porous silicon composite particle 101 that is, the silicon fine particle 103 or the silicon compound particle 105 has an oxide having a thickness of 20 nm or less or a particle size ratio of the silicon fine particle 103 or the silicon compound particle 105 of 10% or less. Even if the layer is formed, there is no problem in characteristics.
  • the oxide layer on the surface of the porous silicon composite particles 101 can be formed by immersing in 0.0001 to 0.1 N nitric acid after removing the second phase. Alternatively, it can also be formed by holding under an oxygen partial pressure of 0.00000001 to 0.02 MPa after removing the second phase. When the oxide layer such as silicon is formed, the porous silicon composite particles 101 become extremely stable in the air and do not need to be handled in a glove box or the like.
  • the average particle size of the particles refers to the average particle size of the primary particles.
  • the particle diameter is measured by using image information of an electron microscope (SEM) and a volume-based median diameter of a dynamic light scattering photometer (DLS).
  • SEM electron microscope
  • DLS dynamic light scattering photometer
  • the particle shape is confirmed in advance using an SEM image
  • the particle size is obtained using image analysis software (for example, “A Image-kun” (registered trademark) manufactured by Asahi Kasei Engineering), or DLS ( For example, it can be measured by DLS-8000 manufactured by Otsuka Electronics Co., Ltd.
  • the average particle size is obtained mainly using a surface scanning electron microscope or a transmission electron microscope.
  • the average column diameter is defined as the column diameter of rod-shaped (columnar) silicon particles having an aspect ratio of 5 or more. Let the average value of this support
  • the average porosity means the ratio of voids in the particles.
  • Submicron pores can be measured by nitrogen gas adsorption method, but when the pore size is wide, electron microscope observation or mercury intrusion method (JIS R 1655 “fine ceramics mercury intrusion method” It is possible to measure by, for example, “a method for measuring the pore size distribution of a molded body”, derived from the relationship between pressure and mercury volume when mercury enters the void).
  • the BET specific surface area can be measured by a nitrogen gas adsorption method.
  • the porous silicon composite particles 101 according to the present invention have a particle size of 0.1 ⁇ m to 1000 ⁇ m depending on the Si concentration of the Si intermediate alloy and the cooling rate when manufacturing the intermediate alloy. Note that the particle size is reduced by decreasing the Si concentration or increasing the cooling rate.
  • the average particle diameter is preferably 0.1 to 50 ⁇ m, more preferably 1 to 30 ⁇ m, and further preferably 5 to 20 ⁇ m. For this reason, when the porous silicon composite particles are small, they are used as aggregates or granules. Further, when the porous silicon composite particles are large, there is no problem even if the porous silicon composite particles are roughly pulverized and used.
  • the silicon intermediate alloy 107 is immersed in the molten metal element.
  • the molten metal element penetrates into the silicon intermediate alloy 107.
  • the intermediate alloy element forms an alloy solid phase with the molten element, and further forms a liquid phase when the molten element permeates. Silicon atoms and complex elements are left in the liquid phase region.
  • the silicon fine particles 103 are precipitated, and an alloy network of silicon atoms and the composite element is formed, and a three-dimensional network structure is formed. That is, as shown in FIG.
  • the intermediate alloy element of the silicon intermediate alloy 107 is eluted into the molten metal to form the second phase 109 and silicon is precipitated as silicon fine particles 103.
  • the second phase 109 is an alloy of an intermediate alloy element and a molten element, or is composed of a molten element substituted for the intermediate alloy element.
  • the silicon compound particles 105 remain as they are without being influenced by the molten metal. These silicon fine particles 103 and silicon compound particles 105 are bonded to each other to form a three-dimensional network structure.
  • the silicon primary crystal of silicon alone or the compound of silicon and the complex element does not cause reaggregation of the silicon atom or complex element even if the molten metal penetrates,
  • the silicon primary crystal and the compound of the complex element remain as they are.
  • Condition 1 The melting point of the molten element is lower than the melting point of silicon by 50K or more. If the melting point of the molten metal is close to the melting point of silicon, condition 1 is necessary because silicon is dissolved in the molten metal when the silicon intermediate alloy is immersed in the molten molten element.
  • Condition 2 Si primary crystals do not occur when silicon and intermediate alloy elements are solidified. When forming an alloy of silicon and an intermediate alloy element, when the silicon concentration increases, a coarse silicon primary crystal is formed in the hypereutectic region.
  • This silicon primary crystal does not cause diffusion or re-aggregation of silicon atoms during the dipping process, and does not form a three-dimensional network structure.
  • Condition 3 The solubility of silicon in the molten metal element is lower than 5 atomic%. This is because when the intermediate alloy element and the molten metal element form the second phase, it is necessary not to include silicon in the second phase.
  • Condition 4 The intermediate alloy element and the molten metal element do not separate into two phases. In the case where the intermediate alloy element and the molten metal element are separated into two phases, the intermediate alloy element is not separated from the silicon intermediate alloy, and diffusion / reaggregation of silicon atoms does not occur. Furthermore, even if the treatment with an acid is performed, the intermediate alloy element remains in the silicon particles.
  • Condition 5 Silicon and complex elements do not separate into two phases. When the silicon and the composite element are easily separated into two phases, the silicon compound particles composed of an alloy of silicon and the composite element cannot be finally obtained.
  • Condition 6 The intermediate alloy element corresponding to the molten metal element does not include a complex element in the selectable elements.
  • the composite element is an element that can be selected as an intermediate alloy element and has the characteristics of the intermediate alloy element as described above, when the molten metal element and the composite element form the second phase and the treatment with the acid is performed The complex element is removed.
  • the combination of the intermediate alloy element, the composite element, and the molten metal element that can be used for producing the porous silicon composite and the porosity of the obtained porous silicon composite are: It becomes as follows.
  • the ratio of the composite element is 1 to 33 atomic% of silicon.
  • the ratio of silicon is 10 atomic% or more with respect to the sum of silicon, the intermediate alloy element, and the complex element, and the value of the maximum Si content in Table 2 below corresponding to the intermediate alloy element (a plurality of intermediate elements)
  • the maximum Si content in Table 2 corresponding to each intermediate alloy element is a value that is prorated according to the ratio of the intermediate alloy element) or less.
  • a composite element and a molten element that can be used in common with each intermediate alloy element are used.
  • X atom%), an intermediate alloy element (Y atom%), and one or more complex elements Z 1 , Z 2 , Z 3 ,... Atom%)
  • Y atomic% is the sum of the ratios of the plurality of intermediate alloy elements.
  • silicon one or more intermediate alloy elements selected from the group consisting of Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Ti, and Zr described in Table 2, and intermediate alloy elements
  • a mixture containing silicon, intermediate alloy elements, and composite elements is heated and melted in a vacuum furnace or the like.
  • an alloy of silicon and an intermediate alloy element and a compound of silicon and a complex element are formed.
  • the molten silicon alloy 13 is dropped from the crucible 15 and solidified while in contact with the rotating steel roll 17 to form a ribbon-like silicon intermediate alloy 19.
  • a linear silicon intermediate alloy is manufactured.
  • the cooling rate during solidification of the silicon intermediate alloy is 10 K / s or more, preferably 100 K / s or more, more preferably 200 K / s or more. This increase in the cooling rate contributes to reducing the size of silicon compound particles generated in the initial stage of solidification microscopically. Making the size of the silicon compound particles fine contributes to shortening the heat treatment time in the next step.
  • the thickness of the ribbon-like silicon intermediate alloy 19 or the linear silicon intermediate alloy is 0.1 ⁇ m to 2 mm, preferably 0.1 to 500 ⁇ m, and more preferably 0.1 to 50 ⁇ m.
  • the silicon intermediate alloy may be in the form of a foil piece having a certain length, unlike a linear shape or a ribbon shape.
  • the silicon intermediate alloy is made of at least one of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Tl, and Zn corresponding to the intermediate alloy elements described in Table 2.
  • Si is spinodal decomposed to form a second phase that is an alloy of the intermediate alloy element and the molten element or a second phase composed of the molten element replaced with the intermediate alloy element.
  • a ribbon-like silicon intermediate alloy 19 or a linear silicon intermediate alloy is dipped in a molten metal 23 of a molten element using a molten metal immersion device 21 as shown in FIG.
  • the molten metal 23 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more. Although immersion in the molten metal 23 depends on the molten metal temperature, it is preferably 5 seconds or more and 10,000 seconds or less. This is because coarse Si grains are produced when immersion is performed for 10,000 seconds or more.
  • the ribbon-like silicon intermediate alloy 19 after the immersion is cooled in a non-oxidizing atmosphere to obtain a composite of the silicon fine particles 103, the silicon compound particles 105, and the second phase 109.
  • the second phase 109 which is an alloy of the intermediate alloy element and the molten element, or the second phase 109 composed of the molten element replaced with the intermediate alloy element is dissolved in at least one of an acid, an alkali, and an organic solvent. Then, only the second phase 109 is removed and washed and dried.
  • the acid may be any acid that dissolves the intermediate alloy element and the molten metal element and does not dissolve silicon, and examples thereof include nitric acid, hydrochloric acid, and sulfuric acid.
  • the second phase 109 is heated and decompressed to remove only the second phase by evaporation.
  • a coarse aggregate of the porous silicon composite particles 101 is obtained, so that the average particle diameter of the aggregate becomes 0.1 ⁇ m to 20 ⁇ m by pulverizing with a ball mill or the like.
  • a silicon intermediate alloy in the form of a powder, a particle, or a lump may be used in place of the linear or ribbon-like silicon intermediate alloy 19.
  • silicon one or more intermediate alloy elements selected from the group consisting of Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Ti, and Zr described in Table 2, and intermediate alloy elements Using a corresponding one or more composite elements shown in Table 2, a mixture containing silicon, intermediate alloy elements, and composite elements is heated and melted in a vacuum furnace or the like.
  • a massive ingot is obtained by a method of producing a substantially spherical grain / powdered silicon intermediate alloy by an atomizing method as shown in FIGS. 5A and 5B or by an ingot producing method shown in FIG. If necessary, a powdery, granular or massive silicon intermediate alloy is produced by a mechanical pulverization method.
  • FIG. 5 (a) shows a gas atomizing apparatus 31 capable of producing a powdered silicon intermediate alloy 39 by a gas atomizing method.
  • the crucible 33 there is a silicon alloy 13 of silicon, an intermediate alloy element, and a composite element dissolved by induction heating or the like.
  • the silicon alloy 13 is dropped from the nozzle 35 and at the same time, a jet gas 36 such as an inert gas or air is ejected.
  • the gas jet flow 38 from the gas injector 37 supplied with is sprayed, the molten metal of the silicon alloy 13 is crushed and solidified as droplets to form a powdered silicon intermediate alloy 39.
  • FIG. 5B shows a rotating disk atomizing device 41 that can manufacture the powdered silicon intermediate alloy 51 by the rotating disk atomizing method.
  • the crucible 43 In the crucible 43, there is a silicon alloy 13 of dissolved silicon, intermediate alloy element, and complex element. This silicon alloy is dropped from the nozzle 45, and the molten silicon alloy 13 is dropped onto a rotating disk 49 that rotates at high speed. Then, a shearing force is applied in the tangential direction to crush and form a powdery silicon intermediate alloy 51.
  • FIG. 6 is a diagram illustrating a process of forming the massive silicon intermediate alloy 57 by the ingot manufacturing method.
  • the molten silicon alloy 13 is put into the mold 55 from the crucible 53. Thereafter, the silicon alloy 13 is cooled in the mold 55 and solidified, and then the mold 55 is removed to obtain a bulk silicon intermediate alloy 57.
  • the bulk silicon intermediate alloy 57 may be used as it is, or may be pulverized as necessary and used as a granular silicon intermediate alloy.
  • the particle size of the powdery, granular or massive silicon intermediate alloy is preferably 10 ⁇ m to 50 mm, more preferably 0.1 to 10 mm, and further preferably 1 to 5 mm.
  • the cooling rate during solidification of the silicon alloy is 0.1 K / s or more. If the thickness of the silicon intermediate alloy is increased to 50 mm or more, the heat treatment time becomes longer, which is not preferable because the particle diameter of the porous silicon composite particles grows and becomes coarse. In that case, the silicon intermediate alloy can be mechanically pulverized to reduce the thickness to 50 mm or less.
  • the silicon intermediate alloy is immersed in the molten metal element shown in Table 2 corresponding to the used intermediate alloy element to form a spinodal decomposition of silicon and a second phase that is an alloy of the intermediate alloy element and the molten element.
  • the oxygen in the molten metal is desirably reduced in advance to 100 ppm or less, preferably 10 ppm or less, more preferably 2 ppm or less. This is because dissolved oxygen in the molten metal reacts with silicon to form silica, and with this as a nucleus, silicon grows in a facet shape and becomes coarse.
  • a countermeasure it can be reduced by a solid reducing material such as charcoal / graphite or a non-oxidizing gas, or an element having a strong affinity for oxygen may be added in advance. Silicon particles are formed for the first time in this dipping process.
  • a solid reducing material such as charcoal / graphite or a non-oxidizing gas, or an element having a strong affinity for oxygen may be added in advance. Silicon particles are formed for the first time in this dipping process.
  • a molten silicon immersion device 61 as shown in FIG. 7A is used, and the granular silicon intermediate alloy 63 is placed in a dipping bowl 65 and dipped in a molten metal 69 of a molten element.
  • the pressing cylinder 67 is moved up and down to give mechanical vibration to the silicon intermediate alloy or molten metal, or to give vibration by ultrasonic waves, as shown in FIG.
  • the reaction can be advanced in a short time by stirring the molten metal using mechanical stirring using the mechanical stirrer 81 and gas injection using the gas blowing plug 83 or electromagnetic force. Then, it is pulled up in a non-oxidizing atmosphere and cooled.
  • the molten metal 69 or 79 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more.
  • the immersion in the molten metal depends on the molten metal temperature, but is preferably 5 seconds or longer and 10,000 seconds or shorter. This is because coarse Si grains are produced when immersion is performed for 10,000 seconds or more.
  • the above-mentioned powdery, granular, and lump shapes of silicon intermediate alloys are simply called silicon powders, particles, and lumps with a small aspect ratio (aspect ratio of 5 or less) depending on the size. It is not strictly defined.
  • the granular silicon intermediate alloys 63, 73, and 93 are represented as granular silicon intermediate alloys on behalf of the aforementioned powdery, granular, and massive silicon intermediate alloys.
  • FIG. 10A a silicon intermediate alloy 111 made of silicon and an intermediate alloy element is formed. Thereafter, the silicon fine particles 103, the silicon compound particles 105, and the second phase 109 are formed as shown in FIG. 10B by immersing in a molten metal obtained by adding a complex element to the molten metal element. Thereafter, as shown in FIG. 10C, the second phase 109 is removed to obtain porous silicon composite particles 101.
  • silicon powder and one or more intermediate alloy element powders selected from the group consisting of Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Ti, and Zr listed in Table 2 are used.
  • Silicon (X atomic%) and intermediate alloy element (Y atomic%) are dissolved so as to satisfy the formula (3).
  • a ribbon-like silicon intermediate alloy 19 or a linear silicon intermediate alloy which is an alloy of silicon and an intermediate alloy element, is used by using a single roll casting machine 11 as shown in FIG. To manufacture.
  • a powdery silicon intermediate alloy is manufactured by an atomizing method as shown in FIGS.
  • a silicon intermediate alloy may be cast into an ingot, which may be mechanically pulverized into a granular shape.
  • the silicon intermediate alloy is made of at least one of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Tl, and Zn corresponding to the intermediate alloy elements described in Table 2.
  • One or more complex elements corresponding to the intermediate alloy elements listed in Table 2 are added to the molten metal element in an amount of 10 atomic% or less, and a total of 20 atomic% or less, respectively.
  • the dipping process uses a molten metal dipping device 21 as shown in FIG.
  • the molten silicon processing apparatus is used to immerse the granular silicon intermediate alloy in the molten metal element.
  • the molten metal 23 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more.
  • immersion in the molten metal 23 depends on the molten metal temperature, it is preferably 5 seconds or more and 10,000 seconds or less. This is because coarse Si grains are produced when immersion is performed for 10,000 seconds or more. This is cooled in a non-oxidizing atmosphere to obtain a composite of silicon fine particles 103, silicon compound particles 105, and second phase 109.
  • the molten element shown in Table 2 corresponding to the intermediate alloy element corresponds to the intermediate alloy element.
  • One or more complex elements selected from the group consisting of the complex elements shown in Table 2 may be added to each of 10 atomic% or less and a total of 20 atomic% or less to be immersed in an alloy bath.
  • porous silicon composite particles having an unprecedented three-dimensional network structure can be obtained.
  • porous silicon composite particles having a substantially uniform pore structure as a whole can be obtained. This is because precipitation of silicon fine particles from the silicon intermediate alloy in the molten metal is performed in the molten metal at a high temperature, so that the molten metal penetrates into the particles.
  • the porous silicon composite particles according to the present invention are used as a negative electrode active material of a lithium ion battery, a negative electrode having a high capacity and a long life can be obtained.
  • the complex element is an element that does not absorb lithium as much as silicon, the complex element is difficult to expand during storage of lithium ions, so that expansion of silicon is suppressed and a longer-life negative electrode is obtained. Can do.
  • silicon compound particles, which are compounds of silicon and a composite element have higher conductivity than silicon, the porous silicon composite particles according to the present invention are more rapidly charged / discharged than normal silicon particles. It can correspond to.
  • Examples 1-1 to 1-16 are examples relating to silicon porous particles
  • Examples 2-1 to 2-16 are examples relating to porous silicon composite particles containing a composite element.
  • Example 1-2 to 1-11 The production conditions for each example and comparative example are summarized in Table 3.
  • porous silicon composites were produced in the same manner as in Example 1-1, except for the production conditions such as the intermediate alloy elements shown in Table 3 and the blending ratio of each element. Got.
  • Example 1-13 to 1-16 porous silicon composites were produced in the same manner as in Example 1-12, except for the production conditions such as the intermediate alloy elements shown in Table 3 and the blending ratio of each element. Got.
  • FIG. 11 shows an SEM photograph of the particles according to Example 1-12
  • FIG. 12 shows an SEM photograph of the particles according to Comparative Example 1-1.
  • FIG. 11 it is observed that a large number of silicon fine particles having a particle diameter of 20 nm to 100 nm are joined together to form porous silicon particles.
  • FIG. 12 a wall-like structure having a thickness of about 5 ⁇ m is observed.
  • the average particle diameter of the silicon fine particles was measured by image information of an electron microscope (SEM). Further, the porous silicon particles were divided into a region near the surface of 50% or more in the radial direction and a particle internal region within 50% in the radial direction, and the ratio of the respective average particle diameters Ds and Di was calculated.
  • the values of Ds / Di were all in the range of 0.5 to 1.5 in the examples, but in Comparative Example 1-2 obtained by the etching method, near the surface compared to the particle internal region. The average particle size of the fine particles in the region was small, and the value of Ds / Di was small.
  • the Si concentration of silicon fine particles and porous silicon particles was measured by an electron beam microanalyzer (EPMA) or energy dispersive X-ray analysis (EDX). All contain 80 atomic% or more of silicon.
  • the average porosity of the porous silicon particles was measured by a mercury intrusion method (JIS R 1655) using a 15 mL cell.
  • the porous silicon particles are divided into a region near the surface of 50% or more in the radial direction and a particle internal region within 50% in the radial direction, and the average porosity Xs and Xi are measured by SEM image information. And the ratio of Xs to Xi was calculated.
  • the value of Xs / Xi is between 0.5 and 1.5, but in Comparative Example 1-2 obtained by the etching method, the pores in the region near the surface compared to the region inside the particle Xs / Xi increased due to the development of the structure.
  • FIG. 13 is an X-ray diffraction grating image obtained by measuring the silicon fine particles constituting the porous silicon particles according to Example 1-12. Diffraction derived from silicon crystals is observed, and point diffraction is obtained, which indicates that the silicon fine particles are composed of single crystal silicon.
  • SBR styrene butadiene rubber
  • BM400B styrene butadiene rubber
  • carboxymethyl cellulose sodium (Daicel) as a thickener to adjust the viscosity of the slurry
  • a slurry was prepared by mixing a 1% by mass solution of Chemical Industry Co., Ltd. at a ratio of 10 parts by mass in terms of solid content.
  • the electrochemical test cell was assembled in a glove box having a dew point of ⁇ 60 ° C. or lower.
  • the charge / discharge characteristics were evaluated by measuring the initial discharge capacity and the discharge capacity after 50 cycles of charge / discharge, and calculating the discharge capacity retention rate.
  • the discharge capacity was calculated based on the total weight of the active material Si effective for occlusion / release of lithium.
  • the current value is charged under a constant current condition of 0.1 C, and the voltage value is reduced to 0.02 V (the redox potential of the reference electrode Li / Li + is based on 0 V, the same applies hereinafter). At that point, charging was stopped.
  • 0.1 C is a current value that can be fully charged in 10 hours.
  • the above charge / discharge cycle was repeated 50 cycles at a charge / discharge rate of 0.1C.
  • the ratio of the discharge capacity when charging / discharging was repeated 50 cycles with respect to the initial discharge capacity was obtained as a percentage, and the discharge capacity retention rate after 50 cycles was determined.
  • Example 1-13 to 1-16 since the silicon particles were large, the characteristics were evaluated using particles that were pulverized and reduced in a mortar.
  • the porous silicon particles of Example 1-13 having a particle size of 130 ⁇ 33 were obtained by pulverizing porous silicon particles having an average particle size of 130 ⁇ m to obtain porous silicon particles having an average particle size of 33 ⁇ m. Means.
  • each example has a higher capacity retention rate after 50 cycles than Comparative Examples 1-1 to 1-3, and the rate of decrease in discharge capacity due to repeated charge and discharge is small, so that the battery life is reduced. Expected to be long.
  • the negative electrode active material is a porous silicon particle having a three-dimensional network structure, even if a volume change of expansion / contraction occurs due to alloying / dealloying of Li and Si during charge / discharge. The silicon particles are not cracked or pulverized, and the discharge capacity retention rate is high.
  • Comparative Example 1-1 pure Si was crystallized as an initial crystal when the intermediate alloy was produced, and a eutectic structure (Si and Mg 2 Si) was formed at the end of solidification.
  • Comparative Example 1-3 since it is a mere silicon particle having no pore structure, it cannot follow the volume change due to charge / discharge, and the cycle characteristics are considered to be poor.
  • Example 2 regarding the porous silicon composite particles containing the composite element will be described.
  • Example 2-2 to 2-8, 2-10, 2-11) The production conditions for each example and comparative example are summarized in Table 5.
  • Examples 2-2 to 2-8, 2-10, and 2-11 are the same as in Example 2 except for the production conditions such as intermediate alloy elements, composite elements, and blending ratios of each element shown in Table 5.
  • a porous silicon composite was obtained.
  • Example 2-4 a continuous ribbon-like silicon alloy could not be formed and was cut at 1 to 2 cm, resulting in a foil piece-like silicon alloy.
  • ⁇ 100 ⁇ m means that the diameter of the linear intermediate alloy is 100 ⁇ m. The same applies to Example 2-8.
  • ⁇ 40 ⁇ m in the granular intermediate alloy means that the average particle diameter of the granular intermediate alloy is 40 ⁇ m.
  • Example 2-13 to 2-16 porous silicon composites were produced in the same manner as in Example 2-12 except that the production conditions such as intermediate alloy elements shown in Table 5 and the blending ratio of each element were used. Particles were obtained. In Examples 2-13, 2-15, and 2-16, the water cooling block was used to increase the cooling rate.
  • FIG. 14 shows an SEM photograph of the surface of the particle according to Example 2-1
  • FIG. 15 shows an SEM photograph of a cross section inside the particle according to Example 2-1
  • FIG. The SEM photograph of the surface of the particle which concerns on is shown.
  • FIG. 14 and FIG. 15 it is observed that a large number of silicon fine particles having a particle diameter of 20 nm to 50 nm are joined together to form porous silicon composite particles.
  • FIG. 14 and FIG. 15 it is observed in FIG. 14 and FIG. 15 that there is no big difference in the porosity and the particle diameter of silicon fine particles.
  • FIG. 16 it is observed that small silicon particles are bonded to large silicide particles.
  • FIG. 17 is an X-ray diffraction grating image of silicon fine particles constituting the silicon composite particles. A spot derived from a crystal of silicon is observed, and it can be seen that the silicon fine particle is a single crystal.
  • FIG. 18 is a TEM photograph of the silicon fine particles constituting the silicon composite particles, and the upper left is a limited-field electron diffraction image in the observation region of the TEM.
  • the TEM photograph it can be seen that there is no grain boundary in one silicon fine particle and it is a single crystal.
  • the limited-field electron diffraction image a spot derived from a silicon crystal is observed, and it can be seen that the silicon fine particle is also a single crystal.
  • the average particle size of the silicon fine particles and the silicon compound particles was measured by image information of an electron microscope (SEM).
  • SEM electron microscope
  • the porous silicon composite particles are divided into a surface vicinity region of 50% or more in the radial direction and a particle internal region of 50% or less in the radial direction, and the respective average particle diameters Ds and Di are obtained from the respective SEM photographs, These ratios were calculated.
  • the values of Ds / Di were all in the range of 0.5 to 1.5 in the examples, but in Comparative Example 2-4 obtained by the etching method, near the surface compared to the particle inner region.
  • the average particle size of the fine particles in the region was small, and the value of Ds / Di was small.
  • the above-described method using SEM observation and DLS was used for the average particle diameter of the porous silicon composite particles.
  • the Si concentration of silicon fine particles and the concentration of Si and complex elements in porous silicon composite particles were measured with an ICP emission spectrometer.
  • the silicon fine particles contain 80 atomic% or more of silicon.
  • the average porosity of the porous silicon composite particles was measured by a mercury intrusion method (JIS R 1655) using a 15 mL cell.
  • the porous silicon composite particles are divided into a surface vicinity region of 50% or more in the radial direction and a particle internal region of 50% or less in the radial direction, and an arbitrary portion in each region is analyzed with a surface scanning electron microscope. Observed, Xs and Xi were obtained as the average porosity, and the ratio of Xs and Xi was calculated. In the examples, the value of Xs / Xi is between 0.5 and 1.5. However, in Comparative Example 2-4 obtained by the etching method, the pores in the region near the surface compared to the region inside the particle Xs / Xi increased due to the development of the structure.
  • SBR styrene butadiene rubber
  • BM400B styrene butadiene rubber
  • carboxymethyl cellulose sodium (Daicel) as a thickener to adjust the viscosity of the slurry
  • a slurry was prepared by mixing a 1% by mass solution of Chemical Industry Co., Ltd. at a ratio of 10 parts by mass in terms of solid content.
  • the electrochemical test cell was assembled in a glove box having a dew point of ⁇ 60 ° C. or lower.
  • the charge / discharge characteristics were evaluated by measuring the initial discharge capacity and the discharge capacity after 50 cycles of charge / discharge, and calculating the discharge capacity retention rate.
  • the discharge capacity was calculated based on the total weight of silicide and active material Si effective for occlusion / release of lithium.
  • the current value is charged under a constant current condition of 0.1 C, and the voltage value is reduced to 0.02 V (the redox potential of the reference electrode Li / Li + is based on 0 V, the same applies hereinafter). At that point, charging was stopped.
  • 0.1 C is a current value that can be fully charged in 10 hours.
  • the above charge / discharge cycle was repeated 50 cycles at a charge / discharge rate of 0.1C.
  • the ratio of the discharge capacity when charging / discharging was repeated 50 cycles with respect to the initial discharge capacity was obtained as a percentage, and the discharge capacity retention rate after 50 cycles was determined.
  • Example 2-13 to 2-16 and Comparative Example 2-3 since the silicon particles were large, the characteristics were evaluated using particles that were pulverized and reduced in a mortar.
  • the average particle size 130 ⁇ 33 of the porous silicon composite particles of Example 2-13 is obtained by pulverizing the porous silicon composite particles having an average particle size of 130 ⁇ m to obtain the porous silicon composite particles having an average particle size of 33 ⁇ m. It means that body particles were obtained.
  • each example has a higher capacity retention rate after 50 cycles than each comparative example, and the rate of decrease in discharge capacity due to repeated charge and discharge is small, so the battery life is expected to be long.
  • the negative electrode active material is a porous silicon composite particle having a three-dimensional network structure, volume change of expansion / contraction occurs due to alloying / dealloying of Li and Si during charge / discharge.
  • the silicon composite particles are not cracked or pulverized, and the discharge capacity retention rate is high.
  • Comparative Example 2-1 pure Si was crystallized as an initial crystal when the intermediate alloy was produced, and a eutectic structure (Si and Mg 2 Si) was formed at the end of solidification.
  • Comparative Example 2-5 since it is a simple particle having no pore structure, it cannot follow the volume change due to charge / discharge, and the cycle characteristics are considered to be poor.
  • the porous silicon composite particles according to the present invention can be used not only for a negative electrode of a lithium ion battery but also as a negative electrode of a lithium ion capacitor, a solar cell, a light emitting material, and a filter material.

Abstract

Porous silicon particles and complex porous silicon particles suitable for negative electrode materials etc. for lithium-ion batteries, which achieve high capacity and good cycling characteristics, are provided. Porous silicon particles formed by the joining of a plurality of silicon microparticles, and having an average particle diameter of 0.1 μm to 1000 μm, a three-dimensional network structure having continuous gaps, an average porosity of 15 to 93%, and a structure in which the particles of a whole particle are uniform. Complex porous silicon particles formed by the joining of a plurality of silicon microparticles and a plurality of silicon compound particles, and characterized by containing a compound of silicon and composite elements, having an average particle diameter of 0.1 μm to 1000 μm, and having a three-dimensional network structure having continuous gaps.

Description

多孔質シリコン粒子及び多孔質シリコン複合体粒子、並びにこれらの製造方法Porous silicon particles, porous silicon composite particles, and production methods thereof
　本発明は、リチウムイオン電池用の負極などに用いられる多孔質シリコン粒子及び多孔質シリコン複合体粒子に関するものである。 The present invention relates to porous silicon particles and porous silicon composite particles used for negative electrodes for lithium ion batteries and the like.
　従来、負極活物質として天然黒鉛、人造黒鉛、無定形炭素、メソフェーズ炭素等の各種炭素系材料やチタン酸リチウム、スズ合金等を用いたリチウムイオン電池が実用化されている。また、負極活物質と、カーボンブラック等の導電助剤と、樹脂の結着剤とを混練してスラリーを調製し、銅箔上に塗布・乾燥して、負極を形成することが行われている。 Conventionally, lithium ion batteries using various carbon-based materials such as natural graphite, artificial graphite, amorphous carbon, and mesophase carbon, lithium titanate, tin alloys, and the like as a negative electrode active material have been put into practical use. Also, a negative electrode is formed by kneading a negative electrode active material, a conductive aid such as carbon black, and a resin binder to prepare a slurry, and applying and drying on a copper foil. Yes.
　一方、高容量化を目指し、リチウム化合物として理論容量の大きな金属や合金、特にシリコンおよびその合金を負極活物質として用いるリチウムイオン電池用の負極が開発されている。しかし、リチウムイオンを吸蔵したシリコンは、吸蔵前のシリコンに対して約４倍まで体積が膨張するため、シリコンを負極活物質として用いた負極は、充放電サイクル時に膨張と収縮を繰り返す。そのため、負極活物質の剥離などが発生し、従来の炭素系活物質からなる負極と比較して、寿命が極めて短いという問題があった。 On the other hand, aiming at higher capacity, negative electrodes for lithium ion batteries using metals and alloys having a large theoretical capacity as lithium compounds, in particular, silicon and its alloys as negative electrode active materials have been developed. However, since the volume of silicon that occludes lithium ions expands to about 4 times that of silicon before occlusion, a negative electrode using silicon as a negative electrode active material repeats expansion and contraction during a charge / discharge cycle. For this reason, the negative electrode active material is peeled off, and there is a problem that the lifetime is extremely short compared to a negative electrode made of a conventional carbon-based active material.
　シリコンを使用した負極の従来の製造方法としては、シリコンを機械的に数マイクロメートルサイズに粉砕し、それに導電性材料を塗布することでリチウム電池用負極材料として使用する技術（例えば、特許文献１を参照）が知られている。
　他に、シリコンを使用した負極の従来の製造方法としては、シリコン基板に陽極酸化を施してスリットなどの溝を形成する方法、リボン状のバルク金属中に微細なシリコンを晶出させる方法（例えば、特許文献２を参照）などがある。
　他に、導電性基板上にポリスチレンやＰＭＭＡなどの高分子の粒子を堆積し、これにリチウムと合金化する金属を鍍金により施した後、高分子の粒子を取り除くことにより金属の多孔体（多孔質体）を作製する技術（例えば、特許文献３を参照）も知られている。
　更に、本発明の中間工程物であるＳｉ中間合金に相当するものを、リチウム電池用負極材料として使用する技術（例えば、特許文献４、５を参照）が知られている。
　また、これを熱処理してリチウム電池用負極材料して使用する技術（例えば、特許文献６を参照）が知られている。
　また、この技術に関連して、急冷凝固技術を応用して作製したＳｉと元素ＭのＳｉ合金から、元素Ｍを酸またはアルカリによって完全に溶出除去する技術（例えば、特許文献７を参照）が知られている。
　更に、メタリック・シリコンをフッ酸、硝酸でエッチングする技術（例えば、特許文献８、９）も知られている。 As a conventional method for manufacturing a negative electrode using silicon, a technique of using silicon as a negative electrode material for a lithium battery by mechanically pulverizing silicon into a size of several micrometers and applying a conductive material thereto (for example, Patent Document 1). Is known).
In addition, as a conventional manufacturing method of a negative electrode using silicon, a method of forming a groove such as a slit by anodizing a silicon substrate, a method of crystallizing fine silicon in a ribbon-like bulk metal (for example, , See Patent Document 2).
In addition, polymer particles such as polystyrene and PMMA are deposited on a conductive substrate, a metal alloying with lithium is plated thereon, and the polymer particles are removed by removing the polymer particles. A technique (see, for example, Patent Document 3) for producing a material is also known.
Furthermore, a technique (for example, see Patent Documents 4 and 5) in which a material corresponding to a Si intermediate alloy which is an intermediate product of the present invention is used as a negative electrode material for a lithium battery is known.
In addition, a technique (for example, see Patent Document 6) in which this is heat-treated and used as a negative electrode material for a lithium battery is known.
Further, in relation to this technique, there is a technique (for example, refer to Patent Document 7) in which the element M is completely eluted and removed with an acid or alkali from a Si alloy of Si and the element M produced by applying the rapid solidification technique. Are known.
Further, a technique for etching metallic silicon with hydrofluoric acid or nitric acid (for example, Patent Documents 8 and 9) is also known.
特許４１７２４４３号公報Japanese Patent No. 4172443 特開２００８－１３５３６４号公報JP 2008-135364 A 特開２００６－２６０８８６号公報JP 2006-260886 A 特開２０００－１４９９３７号公報JP 2000-149937 A 特開２００４－３６２８９５号公報JP 2004-362895 A 特開２００９－０３２６４４号公報JP 2009-032644 A 特許第３８２７６４２号公報Japanese Patent No. 3827642 米国出願公開第２００６／０２５１５６１号明細書US Application Publication No. 2006/0251561 米国出願公開第２００９／０１８６２６７号明細書US Application Publication No. 2009/0186267
　しかしながら、特許文献１の技術は、単結晶シリコンを粉砕して得られる数マイクロメーター・サイズの単結晶で、シリコンの原子が層状あるいは３次元網目構造を有している板もしくは粉末を負極用活物質として使用するものである。更に、導電性を付与させる為に、シリコン化合物（硅素炭化物、硅素シアン化物、硅素窒化物、硅素酸化物、硅素ホウ化物、硅素ホウ酸化物、硅素ホウ窒化物、硅素オキシナイトライド、硅素アルカリ金属合金、硅素アルカリ土類金属合金、硅素遷移金属合金からなる硅素化合物群のうちの一種以上）を使用するものである。しかし、シリコンは、充放電時の体積変化が大きいため、特許文献１に記載の負極活物質は、充放電時に、負極活物質の微粉化と負極活物質の剥離、負極の亀裂の発生、負極活物質間の導電性の低下などが発生して容量が低下する。それゆえ、サイクル特性が悪く、二次電池の寿命が短いという問題点があった。特に、負極材料としての実用化が期待されているシリコンは、充放電時の体積変化が大きいため、割れが発生しやすく、充放電サイクル特性が悪いという問題点があった。 However, the technique of Patent Document 1 is a single crystal having a size of several micrometers obtained by pulverizing single crystal silicon, and a plate or powder in which silicon atoms have a layered or three-dimensional network structure is used for the negative electrode. It is used as a substance. Further, in order to impart conductivity, silicon compounds (silicon carbide, silicon cyanide, silicon nitride, silicon oxide, silicon boride, silicon borate, silicon boronitride, silicon oxynitride, silicon alkali metal) One or more of a silicon compound group consisting of an alloy, a silicon alkaline earth metal alloy, and a silicon transition metal alloy). However, since silicon has a large volume change at the time of charging / discharging, the negative electrode active material described in Patent Document 1 is finely pulverized negative electrode active material, peeling of the negative electrode active material, generation of cracks in the negative electrode, A decrease in electrical conductivity between the active materials occurs and the capacity decreases. Therefore, there are problems that the cycle characteristics are poor and the life of the secondary battery is short. In particular, silicon, which is expected to be put to practical use as a negative electrode material, has a problem that cracking easily occurs and charge / discharge cycle characteristics are poor because the volume change during charge / discharge is large.
　また、特許文献２の技術は、負極活物質と導電助剤と結着剤とのスラリーを塗布・乾燥して、負極を形成する。このような従来の負極は、負極活物質と集電体とを導電性の低い樹脂の結着剤で結着しており、樹脂の使用量は内部抵抗が大きくならないように最小限に抑える必要があり、結合力が弱い。シリコンは、充放電時の体積変化が大きいため、特許文献２の技術では、負極活物質は、充放電時に、負極活物質の微粉化と負極活物質の剥離、負極の亀裂の発生、負極活物質間の導電性の低下などが発生して容量が低下する。それゆえ、サイクル特性が悪く、二次電池の寿命が短いという問題点があった。 In the technique of Patent Document 2, a negative electrode is formed by applying and drying a slurry of a negative electrode active material, a conductive additive and a binder. In such a conventional negative electrode, the negative electrode active material and the current collector are bound with a binder of a resin having low conductivity, and the amount of resin used must be minimized so that the internal resistance does not increase. There is a weak binding force. Since silicon has a large volume change at the time of charging / discharging, in the technique of Patent Document 2, the negative electrode active material is pulverized from the negative electrode active material and peeled off from the negative electrode active material, generation of cracks in the negative electrode, A decrease in conductivity between substances occurs, resulting in a decrease in capacity. Therefore, there are problems that the cycle characteristics are poor and the life of the secondary battery is short.
　また、特許文献３の技術は、導電性基板上にポリスチレンやＰＭＭＡなどの高分子の粒子を堆積し、これにリチウムと合金化する金属を鍍金により施した後、高分子の粒子を取り除くことにより金属の多孔体（多孔質体）を作製することができる。しかし、Ｓｉのポーラス体を作製する上では、ポリスチレンやＰＭＭＡなどの高分子の粒子にＳｉをめっきすることは極めて困難であり、工業的に適応できないという問題点があった。 In the technique of Patent Document 3, polymer particles such as polystyrene and PMMA are deposited on a conductive substrate, a metal alloying with lithium is applied thereto by plating, and then the polymer particles are removed. A metal porous body (porous body) can be produced. However, in producing a Si porous body, there is a problem that it is extremely difficult to plate Si on polymer particles such as polystyrene and PMMA, which is not industrially applicable.
　また、特許文献４の技術は、合金粒子を構成する原料の溶融物を凝固速度が１００℃／秒以上となるように冷却して凝固させて、Ｓｉ相粒とこれを少なくとも部分的に包囲するＳｉ含有固溶体又は金属間化合物の相とを含む合金を形成する工程、を含むことを特徴とする、非水電解質二次電池用負極材料の製造する方法である。しかし、この方法ではＬｉが反応する上で、包括するＳｉ含有固溶体内を拡散移動することが必要であり反応性に乏しく、更に充放電に寄与できるＳｉの含有量が少ないという点から実用化には至っていない。 Further, the technique of Patent Document 4 cools and solidifies the raw material melt constituting the alloy particles so that the solidification rate is 100 ° C./second or more, and at least partially surrounds the Si phase grains. Forming a negative electrode material for a non-aqueous electrolyte secondary battery, comprising: forming an alloy containing a Si-containing solid solution or an intermetallic compound phase. However, in this method, when Li reacts, it is necessary to diffuse and move through the included Si-containing solid solution, the reactivity is poor, and further, the practical application from the point that the content of Si that can contribute to charge and discharge is small. Has not reached.
　また、特許文献５の技術は、ケイ素（ケイ素の含有率は、２２質量％以上６０質量％以下）と、銅，ニッケルおよびコバルトのいずれか１種または２種以上の金属元素とを含有するケイ素合金粉末により構成されている。これを単ロール法またはアトマイズ法により合成することで、リチウムイオンなどの吸蔵・放出による体積変化に基づく微粉化を抑制するものである。しかし、この方法ではＬｉが反応する上で、包括するＳｉ含有固溶体内を拡散移動することが必要であり反応性に乏しく、更に充放電に寄与できるＳｉの含有量が少ないという点から実用化には至っていない。 In addition, the technique of Patent Document 5 discloses silicon containing silicon (the silicon content is 22% by mass or more and 60% by mass or less) and one or more metal elements of copper, nickel, and cobalt. It is composed of alloy powder. By synthesizing this by a single roll method or an atomizing method, pulverization based on volume change due to occlusion / release of lithium ions or the like is suppressed. However, in this method, when Li reacts, it is necessary to diffuse and move through the included Si-containing solid solution, the reactivity is poor, and further, the practical application from the point that the content of Si that can contribute to charge and discharge is small. Has not reached.
　また、特許文献６の技術は、Ｓｉと、Ｃｏ、Ｎｉ、Ａｇ、Ｓｎ、Ａｌ、Ｆｅ、Ｚｒ、Ｃｒ、Ｃｕ、Ｐ、Ｂｉ、Ｖ、Ｍｎ、Ｎｂ、Ｍｏ、Ｉｎおよび希土類元素から選択される１種または２種以上の元素とを含む合金溶湯を急冷し、Ｓｉ基アモルファス合金を得る工程と、得られたＳｉ基アモルファス合金を熱処理する工程を含む。Ｓｉ基アモルファス合金を熱処理することにより、数十ｎｍ～３００ｎｍ程度の微細な結晶性のＳｉ核を析出させるものである。しかし、この方法ではＬｉが反応する上で、包括するＳｉ含有固溶体内を拡散移動することが必要であり反応性に乏しく、更に充放電に寄与できるＳｉの含有量が少ないという点から実用化には至っていない。 The technique of Patent Document 6 is selected from Si, Co, Ni, Ag, Sn, Al, Fe, Zr, Cr, Cu, P, Bi, V, Mn, Nb, Mo, In, and rare earth elements. It includes a step of rapidly cooling a molten alloy containing one or more elements and obtaining a Si-based amorphous alloy and a step of heat-treating the obtained Si-based amorphous alloy. By heat-treating the Si-based amorphous alloy, fine crystalline Si nuclei of about several tens of nm to 300 nm are precipitated. However, in this method, when Li reacts, it is necessary to diffuse and move through the included Si-containing solid solution, the reactivity is poor, and further, the practical application from the point that the content of Si that can contribute to charge and discharge is small. Has not reached.
　また、特許文献７の技術は、非晶質リボンや微粉末などを製造する際に適応するものであり、冷却速度は専ら１０４Ｋ／秒以上で凝固させるものである。一般的な合金の凝固においては、１次デンドライトが成長しながら２次デンドライトが成長する樹枝状結晶をとる。特殊な合金系（Ｃｕ－Ｍｇ系、Ｎｉ－Ｔｉ系など）では、１０４Ｋ／秒以上で非晶質金属を形成させることができるが、その他の系（例えばＳｉ－Ｎｉ系）では冷却速度は専ら１０４Ｋ／秒以上で凝固させても非晶質金属を得ることができず、結晶相が形成される。この結晶相が形成される場合の結晶のサイズは、冷却速度（Ｒ：Ｋ／秒）とデンドライト・アーム・スペーシング（ＤＡＳ：μｍ）の関係に順ずる。
　ＤＡＳ＝Ａ×ＲＢ　（一般に、Ａ：４０～１００、Ｂ：－０．３～－０．４）
　そのために、結晶相を有する場合、例えばＡ：６０、Ｂ：－０．３５の場合に、Ｒ：１０４Ｋ／秒でＤＡＳは１μｍとなる。結晶相もこのサイズに準ずるもので、１０ｎｍなどの微細な結晶相を得ることはできない。これらの理由から、Ｓｉ－Ｎｉ系などの材料では、この急冷凝固技術単独で微細な結晶相からなる多孔質を得ることができない。 The technique of Patent Document 7 is applied when producing an amorphous ribbon or fine powder, and solidifies at a cooling rate of 10 4 K / second or more. In the solidification of a general alloy, dendrites in which secondary dendrite grows while primary dendrite grows are taken. A special alloy system (Cu-Mg system, Ni-Ti system, etc.) can form an amorphous metal at 10 4 K / second or more, but other systems (eg, Si-Ni system) have a cooling rate. Even when solidified at 10 4 K / second or more, an amorphous metal cannot be obtained, and a crystalline phase is formed. The size of the crystal when this crystal phase is formed follows the relationship between the cooling rate (R: K / sec) and the dendrite arm spacing (DAS: μm).
DAS = A × R B (generally A: 40 to 100, B: −0.3 to −0.4)
Therefore, in the case of having a crystal phase, for example, when A: 60 and B: −0.35, DAS becomes 1 μm at R: 10 4 K / sec. The crystal phase conforms to this size, and a fine crystal phase such as 10 nm cannot be obtained. For these reasons, it is not possible to obtain a porous material composed of a fine crystal phase with this rapid solidification technique alone with materials such as Si—Ni.
　また、特許文献８、９の技術は、金属シリコンをフッ酸や硝酸を用いてエッチングして表面に微細な空孔を作成するものである。しかし、ＢＥＴ比表面積が１４０～４００ｍ２／ｇと充放電の応答性の観点からＳｉ負極用活物質としては不十分である問題点があった。しかし、エッチングにより形成された空孔は、粒子の内部ほど形成されにくい傾向があり、その結果、粒子表面から中心まで空孔が均一に存在せず、粒子中心付近に粗大なシリコン粒が形成される。そのため、充放電時の体積膨張収縮に伴い、粒子内部で微粉化が進み、寿命が短いという問題点があった。 In the techniques of Patent Documents 8 and 9, metal silicon is etched using hydrofluoric acid or nitric acid to create fine holes on the surface. However, there is a problem that the BET specific surface area is 140 to 400 m 2 / g, which is insufficient as an active material for Si negative electrode from the viewpoint of charge / discharge response. However, vacancies formed by etching tend to be harder to form as the inside of the particles. As a result, vacancies do not exist uniformly from the particle surface to the center, and coarse silicon grains are formed near the particle center. The Therefore, with the volume expansion and contraction during charging / discharging, there is a problem that pulverization progresses inside the particles and the life is short.
　本発明は、前述した問題点に鑑みてなされたもので、その目的とすることは、高容量と良好なサイクル特性を実現するリチウムイオン電池用の負極材料などに好適な多孔質シリコン粒子及び多孔質シリコン複合体粒子を得ることである。 The present invention has been made in view of the above-described problems, and its object is to provide porous silicon particles and porous materials suitable for a negative electrode material for a lithium ion battery that realizes high capacity and good cycle characteristics. It is to obtain a porous silicon composite particle.
　本発明者は、上記目的を達成するために鋭意検討した結果、シリコン合金のスピノーダル分解（シリコン合金からの溶湯内でのシリコンの析出）と、脱成分腐食（ｄｅａｌｌｏｙｉｎｇ）により、微細な多孔質なシリコンが得られることを見出した。シリコン合金からの溶湯内でのシリコンの析出は、高温の溶融金属中で行うため、脱成分腐食（ｄｅａｌｌｏｙｉｎｇ）により得た多孔質シリコン粒子の表層部と内部とで一次粒子径や空隙率に大きな分布が発生しにくい。一方、例えば、酸によるエッチングでは、粒子内部は脱成分元素の濃度拡散に制約が生じるため、粒子表層部の気孔率は大きくなり、粒子内部の気孔率は小さくなる。条件によっては、粒子中心部に気孔のないＳｉの芯が残留し、この中心部の粗大なＳｉがＬｉとの反応時に微粉化が生じ、サイクル特性が劣る。本発明は、この知見に基づきなされたものである。 As a result of intensive studies to achieve the above object, the present inventor has found that a fine porous material is formed by spinodal decomposition of silicon alloy (precipitation of silicon in the molten metal from the silicon alloy) and dealloying (dealloying). It has been found that silicon can be obtained. Since silicon is precipitated in the molten metal from the silicon alloy in a high-temperature molten metal, the primary particle diameter and porosity are large in the surface layer portion and the inside of the porous silicon particles obtained by dealloying (dealloying). Distribution is unlikely to occur. On the other hand, for example, in etching with an acid, the concentration inside the particle is restricted in the diffusion of decomponent elements, so the porosity of the particle surface layer portion increases and the porosity inside the particle decreases. Depending on the conditions, a Si core having no pores remains in the center of the particle, and the coarse Si in the center is pulverized during the reaction with Li, resulting in poor cycle characteristics. The present invention has been made based on this finding.
　すなわち、以下の発明を提供するものである。
（１）複数のシリコン微粒子が接合してなる多孔質シリコン粒子であって、前記多孔質シリコン粒子の平均粒径が０．１μｍ～１０００μｍであり、前記多孔質シリコン粒子は連続した空隙を有する三次元網目構造を有し、前記多孔質シリコン粒子の平均空隙率が１５～９３％であり、半径方向で５０％以上の表面近傍領域の空隙率Ｘｓと、半径方向で５０％以内の粒子内部領域の空隙率Ｘｉの比であるＸｓ／Ｘｉが、０．５～１．５であり、酸素を除く元素の比率でシリコンを８０原子％以上含むことを特徴とする多孔質シリコン粒子。
（２）前記シリコン微粒子が、平均粒径または平均支柱径が２ｎｍ～２μｍであり、半径方向で５０％以上の表面近傍領域の前記シリコン微粒子の平均粒径Ｄｓと、半径方向で５０％以内の粒子内部領域の前記シリコン微粒子の平均粒径Ｄｉの比であるＤｓ／Ｄｉが、０．５～１．５であり、前記シリコン微粒子が、酸素を除く元素の比率でシリコンを８０原子％以上含むことを特徴とする中実なシリコン微粒子であることを特徴とする（１）に記載の多孔質シリコン粒子。
（３）前記シリコン微粒子間の接合部の面積が、前記シリコン微粒子の表面積の３０％以下であることを特徴とする（１）に記載の多孔質シリコン粒子。
（４）複数のシリコン微粒子と複数のシリコン化合物粒子が接合してなる多孔質シリコン複合体粒子であって、前記シリコン化合物粒子は、シリコンと、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｏ、Ｃｒ、Ｃｕ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｌｕ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素との化合物を含み、前記多孔質シリコン複合体粒子の平均粒径が、０．１μｍ～１０００μｍであり、多孔質シリコン複合体粒子が、連続した空隙からなる三次元網目構造を有することを特徴とする多孔質シリコン複合体粒子。
（５）前記シリコン微粒子の平均粒径または平均支柱径が、２ｎｍ～２μｍであり、前記シリコン微粒子が、酸素を除く元素の比率でシリコンを８０原子％以上含む中実なシリコン微粒子であることを特徴とする（４）に記載の多孔質シリコン複合体粒子。
（６）前記シリコン化合物粒子の平均粒径が５０ｎｍ～５０μｍであり、前記シリコン化合物粒子が、酸素を除く元素の比率で、５０～９０原子％のシリコンを含むことを特徴とする中実なシリコン化合物の粒子であることを特徴とする（４）に記載の多孔質シリコン複合体粒子。
（７）前記多孔質シリコン複合体粒子の半径方向で５０％以上の表面近傍領域の前記シリコン微粒子の平均粒径Ｄｓと、前記多孔質シリコン複合体粒子の半径方向で５０％以内の粒子内部領域の前記シリコン微粒子の平均粒径Ｄｉの比であるＤｓ／Ｄｉが、０．５～１．５であることを特徴とする（４）に記載の多孔質シリコン複合体粒子。
（８）前記多孔質シリコン複合体粒子の半径方向で５０％以上の表面近傍領域の空隙率Ｘｓと、前記多孔質シリコン複合体粒子の半径方向で５０％以内の粒子内部領域の空隙率Ｘｉの比であるＸｓ／Ｘｉが、０．５～１．５であることを特徴とする（４）に記載の多孔質シリコン複合体粒子。
（９）シリコンと、一つ以上の表１に記載の中間合金元素との合金であり、シリコンの割合が全体の１０原子％以上であり、含有する前記中間合金元素に対応する表１中のＳｉ最大含有量の中で最も高い値以下であるシリコン中間合金を作製する工程（ａ）と、前記中間合金元素に対応する表１記載の１つ以上の溶湯元素の溶湯に浸漬させることで、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記中間合金元素と前記溶湯元素の合金および／または前記中間合金元素と置換した前記溶湯元素で構成されることを特徴とする多孔質シリコン粒子の製造方法。
（１０）前記工程（ａ）において、前記シリコン中間合金が、厚さ０．１μｍ～２ｍｍのリボン状、箔片状または線状であるか、粒径１０μｍ～５０ｍｍの粒状または塊状であることを特徴とする（９）に記載の多孔質シリコン粒子の製造方法。
（１１）前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくとも１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする（９）に記載の多孔質シリコン粒子の製造方法。
（１２）前記工程（ａ）が、前記シリコンと前記中間合金元素の溶湯を、単ロール鋳造機によりリボン状のシリコン中間合金を製造する工程であることを特徴とする（９）に記載の多孔質シリコン粒子の製造方法。
（１３）前記工程（ａ）が、前記シリコンと前記中間合金元素の溶湯を、ガスアトマイズ法又は回転円盤アトマイズ法を用いて粉末状のシリコン中間合金を製造する工程であることを特徴とする（９）に記載の多孔質シリコン粒子の製造方法。
（１４）前記工程（ａ）が、前記シリコンと前記中間合金元素の溶湯を、鋳型内にて冷却して塊状のシリコン中間合金を製造する工程を含むことを特徴とする（９）に記載の多孔質シリコン粒子の製造方法。
（１５）Ｃｕにシリコンの割合が全体の１０～３０原子％になるようにシリコンを配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を製造する工程（ａ）と、前記シリコン合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記工程（ｂ）で前記第２相が、前記Ｃｕと前記溶湯元素の合金および／または前記Ｃｕと置換した前記溶湯元素で構成されることを特徴とする多孔質シリコン粒子の製造方法。
（１６）Ｍｇにシリコンの割合が全体の１０～５０原子％になるようにシリコンを配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を製造する工程（ａ）と、前記シリコン合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記工程（ｂ）で前記第２相が、前記Ｍｇと前記溶湯元素の合金および／または前記Ｍｇと置換した前記溶湯元素で構成されることを特徴とする多孔質シリコン粒子の製造方法。
（１７）Ｎｉにシリコンの割合が全体の１０～５５原子％になるようにシリコンを配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を製造する工程（ａ）と、前記シリコン合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、前記工程（ｂ）で前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｎｉと前記溶湯元素の合金および／または前記Ｎｉと置換した前記溶湯元素で構成されることを特徴とする多孔質シリコン粒子の製造方法。
（１８）Ｔｉにシリコンの割合が全体の１０～８２原子％になるようにシリコンを配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を製造する工程（ａ）と、前記シリコン合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記工程（ｂ）で前記第２相が、前記Ｔｉと前記溶湯元素の合金および／または前記Ｔｉと置換した前記溶湯元素で構成されることを特徴とする多孔質シリコン粒子の製造方法。
（１９）シリコンと、１つ以上の表２に記載の中間合金元素と、１つ以上の表２に記載の複合体元素との合金であり、前記複合体元素の割合が前記シリコンの１～３３原子％であり、前記シリコンの割合が前記シリコンと前記中間合金元素と前記複合体元素の和に対して１０原子％以上であり、含有する前記中間合金元素に対応する表２中のＳｉ最大含有量の値以下であるシリコン中間合金を作製する工程（ａ）と、前記中間合金元素に対応する表２記載の１つ以上の溶湯元素の溶湯に浸漬させて、シリコン微粒子と、シリコンと複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記中間合金元素と前記溶湯元素の合金及び／又は前記溶湯元素で構成されることを特徴とする多孔質シリコン複合体粒子の製造方法。
（２０）前記工程（ａ）において、シリコン（Ｘ原子％）と中間合金元素（Ｙ原子％）と１つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）が、以下の式を満足する組成を有するシリコン中間合金を作製することを特徴とする（１９に記載の多孔質シリコン複合体粒子の製造方法。
１０≦Ｘ＜[Ｓｉ最大含有量]　　式（１）
１０≦ａ÷（ａ＋Ｙ）×１００≦[Ｓｉ最大含有量]　　式（２）
但し、ａ＝Ｘ－１．５×（Ｚ１+Ｚ２+Ｚ３、・・・・）［Ｓｉ最大含有量］は、含有する中間合金元素に対応する表２中のＳｉ最大含有量である。
（２１）シリコンと、表２に記載の一つ以上の中間合金元素との合金であり、シリコンの割合が全体の１０原子％以上であり、含有する前記中間合金元素に対応する表２中のＳｉ最大含有量の中で最も高い値以下であるシリコン中間合金を作成する工程（ａ）と、前記中間合金元素に対応する表２記載の１つ以上の溶湯元素の溶湯であって、前記中間合金元素に対応する表２記載の１つ以上の複合体元素を各１０原子％以下、合計２０原子％以下含む合金浴に浸漬させて、シリコン微粒子と、シリコンと複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記中間合金元素と前記溶湯元素の合金及び／又は前記溶湯元素で構成されることを特徴とする多孔質シリコン複合体粒子の製造方法。
（２２）前記工程（ａ）において、前記シリコン中間合金が、厚さ０．１μｍ～２ｍｍのリボン状、箔片状または線状であるか、粒径１０μｍ～５０ｍｍの粉末状、粒状または塊状であることを特徴とする（１９）に記載の多孔質シリコン複合体粒子の製造方法。
（２３）前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする（１９）に記載の多孔質シリコン複合体粒子の製造方法。
（２４）前記工程（ａ）が、前記シリコンと前記中間合金元素と前記複合体元素の溶湯を、単ロール鋳造機もしくは双ロール鋳造機によりリボン状もしくは薄板状のシリコン中間合金を製造する工程であることを特徴とする（１９）に記載の多孔質シリコン複合体粒子の製造方法。
（２５）前記工程（ａ）が、前記シリコンと前記中間合金元素と前記複合体元素の溶湯を、アトマイズ法を用いて粉末状のシリコン中間合金を製造する工程であることを特徴とする（１９）に記載の多孔質シリコン複合体粒子の製造方法。
（２６）前記工程（ａ）が、前記シリコンと前記中間合金元素と前記複合体元素の溶湯を、鋳型内にて冷却して塊状のシリコン中間合金を製造する工程を含むことを特徴とする（１９）に記載の多孔質シリコン複合体粒子の製造方法。
（２７）Ｃｕ（Ｙ原子％）に、シリコンの割合が全体に対して１０～３０原子％（Ｘ原子％）で、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｏ、Ｃｒ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）を（２０）の式（１）、（２）を満足するように配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粉末状・粒状・塊状のシリコン中間合金を作成する工程（ａ）と、前記シリコン中間合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｃｕと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする多孔質シリコン複合体粒子の製造方法。
（２８）Ｃｕ（Ｙ原子％）に、シリコンの割合が全体に対して１０～３０原子％（Ｘ原子％）を配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を作成する工程（ａ）と、前記シリコン中間合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯にＡｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｏ、Ｃｒ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作成された合金浴へ浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｃｕと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする多孔質シリコン複合体粒子の製造方法。
（２９）Ｍｇ（Ｙ原子％）に、シリコンの割合が全体に対して１０～５０原子％（Ｘ原子％）で、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）を（２０）の式（１）、（２）を満足するように配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粉末状・粒状・塊状のシリコン中間合金を作成する工程（ａ）と、前記シリコン中間合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｍｇと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする多孔質シリコン複合体粒子の製造方法。
（３０）Ｍｇ（Ｙ原子％）に、シリコンの割合が全体に対して１０～５０原子％（Ｘ原子％）を配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を作成する工程（ａ）と、前記シリコン中間合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯にＡｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作成された合金浴へ浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｍｇと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする多孔質シリコン複合体粒子の製造方法。
（３１）Ｎｉ（Ｙ原子％）に、シリコンの割合が全体に対して１０～５５原子％（Ｙ原子％）で、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）を（２０）の式（１）、（２）を満足するように配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粉末状・粒状・塊状のシリコン中間合金を作成する工程（ａ）と、前記シリコン中間合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｎｉと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする多孔質シリコン複合体粒子の製造方法。
（３２）Ｎｉ（Ｙ原子％）に、シリコンの割合が全体に対して１０～５５原子％（Ｙ原子％）を配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を作成する工程（ａ）と、前記シリコン中間合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯にＡｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作成された合金浴へ浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｎｉと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする多孔質シリコン複合体粒子の製造方法。
（３３）Ｔｉ（Ｙ原子％）に、シリコンの割合が全体に対して１０～８０原子％（Ｙ原子％）で、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｌｕ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）を（２０）の式（１）、（２）を満足するように配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粉末状・粒状・塊状のシリコン中間合金を作成する工程（ａ）と、前記シリコン中間合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｔｉと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする多孔質シリコン複合体粒子の製造方法。
（３４）Ｔｉ（Ｙ原子％）に、シリコンの割合が全体に対して１０～８０原子％（Ｙ原子％）を配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を作成する工程（ａ）と、前記シリコン中間合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯にＡｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｌｕ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作成された合金浴へ浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、前記第２相を取り除く工程（ｃ）と、を具備し、前記第２相が、前記Ｔｉと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする多孔質シリコン複合体粒子の製造方法。 That is, the following invention is provided.
(1) Porous silicon particles formed by bonding a plurality of silicon fine particles, wherein the porous silicon particles have an average particle size of 0.1 μm to 1000 μm, and the porous silicon particles have a tertiary structure having continuous voids. The porous silicon particles have an original network structure, the average porosity of the porous silicon particles is 15 to 93%, the porosity Xs of the surface vicinity region of 50% or more in the radial direction, and the particle internal region of 50% or less in the radial direction A porous silicon particle characterized in that Xs / Xi, which is a ratio of the porosity Xi, is 0.5 to 1.5 and contains 80 atomic% or more of silicon in a ratio of elements excluding oxygen.
(2) The silicon fine particles have an average particle diameter or average column diameter of 2 nm to 2 μm, and an average particle diameter Ds of the silicon fine particles in the surface vicinity region of 50% or more in the radial direction is within 50% in the radial direction. The ratio Ds / Di, which is the ratio of the average particle diameter Di of the silicon fine particles in the particle internal region, is 0.5 to 1.5, and the silicon fine particles contain 80 atomic% or more of silicon in the ratio of elements excluding oxygen. The porous silicon particle according to (1), which is a solid silicon fine particle characterized by the above.
(3) The porous silicon particles according to (1), wherein the area of the junction between the silicon fine particles is 30% or less of the surface area of the silicon fine particles.
(4) Porous silicon composite particles formed by joining a plurality of silicon fine particles and a plurality of silicon compound particles, wherein the silicon compound particles are silicon, As, Ba, Ca, Ce, Co, Cr, Cu , Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti , Tm, U, V, W, Y, Yb, Zr, and a compound with one or more composite elements selected from the group consisting of Tm, U, V, W, Y, Yb, Zr, and the average particle size of the porous silicon composite particles is 0.1 μm A porous silicon composite particle having a size of ˜1000 μm and a porous silicon composite particle having a three-dimensional network structure composed of continuous voids.
(5) The silicon fine particles have an average particle diameter or average column diameter of 2 nm to 2 μm, and the silicon fine particles are solid silicon fine particles containing 80 atomic% or more of silicon in a ratio of elements excluding oxygen. The porous silicon composite particles according to (4), characterized in that
(6) Solid silicon, wherein the silicon compound particles have an average particle diameter of 50 nm to 50 μm, and the silicon compound particles contain 50 to 90 atomic% of silicon in a ratio of elements excluding oxygen. The porous silicon composite particles according to (4), wherein the porous silicon composite particles are compound particles.
(7) The average particle diameter Ds of the silicon fine particles in the surface vicinity region of 50% or more in the radial direction of the porous silicon composite particles, and the particle internal region of 50% or less in the radial direction of the porous silicon composite particles The porous silicon composite particles according to (4), wherein Ds / Di, which is the ratio of the average particle diameter Di of the silicon fine particles, is 0.5 to 1.5.
(8) The porosity Xs of the region near the surface of 50% or more in the radial direction of the porous silicon composite particles and the porosity Xi of the particle internal region within 50% in the radial direction of the porous silicon composite particles. The porous silicon composite particle according to (4), wherein the ratio Xs / Xi is 0.5 to 1.5.
(9) It is an alloy of silicon and one or more intermediate alloy elements described in Table 1, and the ratio of silicon is 10 atomic% or more of the whole. Step (a) for producing a silicon intermediate alloy having a maximum Si content of not more than the highest value, and immersing in a melt of one or more melt elements shown in Table 1 corresponding to the intermediate alloy element, A step (b) of separating the silicon fine particles into a second phase, and a step (c) of removing the second phase, wherein the second phase comprises an alloy of the intermediate alloy element and the molten element, and A method for producing porous silicon particles, comprising: the molten metal element substituted with the intermediate alloy element.
(10) In the step (a), the silicon intermediate alloy has a ribbon shape, a foil piece shape or a linear shape with a thickness of 0.1 μm to 2 mm, or a granular shape or a lump shape with a particle size of 10 μm to 50 mm. The method for producing porous silicon particles according to (9), which is characterized in that
(11) In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali, and an organic solvent, or only the second phase is evaporated by heating and decompressing. The method for producing porous silicon particles according to (9), further comprising a step of removing them.
(12) The porous material according to (9), wherein the step (a) is a step of producing a ribbon-shaped silicon intermediate alloy from a molten metal of the silicon and the intermediate alloy element using a single roll casting machine. For producing fine silicon particles.
(13) The step (a) is a step of producing a powdery silicon intermediate alloy by using a gas atomization method or a rotating disk atomization method with a molten metal of the silicon and the intermediate alloy element (9) ) For producing porous silicon particles.
(14) The step (a) includes a step of cooling the molten metal of silicon and the intermediate alloy element in a mold to produce a lump silicon intermediate alloy, according to (9) A method for producing porous silicon particles.
(15) Silicon is blended with Cu so that the ratio of silicon is 10 to 30 atomic% of the total, and the ribbon shape, foil piece shape, linear shape with a thickness of 0.1 μm to 2 mm, or the particle size of 10 μm to 50 mm The step (a) of producing a granular / lumped silicon intermediate alloy, and the silicon alloy as a main component comprising at least one molten element selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, Zn A step (b) of immersing in the molten metal to separate the silicon fine particles and the second phase, and a step (c) of removing the second phase, wherein the second step in the step (b). A method for producing porous silicon particles, wherein the phase is composed of an alloy of the Cu and the molten element and / or the molten element substituted for the Cu.
(16) Silicon is mixed with Mg so that the ratio of silicon is 10 to 50 atomic%, and the thickness is 0.1 μm to 2 mm in ribbon shape, foil piece shape, linear shape, or particle size of 10 μm to 50 mm. The step (a) for producing a granular / lumped silicon intermediate alloy, and the silicon alloy is selected from the group consisting of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, Tl, and Zn. A step (b) of immersing in a molten metal containing at least one molten element as a main component to separate into silicon fine particles and a second phase, and a step (c) of removing the second phase, The method for producing porous silicon particles, wherein in the step (b), the second phase is composed of an alloy of the Mg and the molten metal element and / or the molten metal element substituted for the Mg.
(17) Ni is blended with Ni so that the silicon content is 10 to 55 atomic% of the total, and ribbons, foil pieces, and wires with a thickness of 0.1 μm to 2 mm, or a particle size of 10 μm to 50 mm The step (a) of producing a granular / lumped silicon intermediate alloy, and the silicon alloy as a main component comprising at least one molten element selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, Zn A step (b) of immersing in the molten metal to separate the silicon fine particles and the second phase, and a step (c) of removing the second phase in the step (b). A method for producing porous silicon particles, characterized in that a phase is composed of an alloy of Ni and the molten element and / or the molten element substituted for Ni.
(18) Silicon is mixed with Ti so that the silicon ratio is 10 to 82 atomic% of the whole, and the thickness is 0.1 μm to 2 mm in ribbon shape, foil piece shape, linear shape, or particle size of 10 μm to 50 mm. The step (a) for producing a granular / lumped silicon intermediate alloy, and the silicon alloy is selected from the group consisting of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Zn A step (b) of immersing in a molten metal containing at least one molten element as a main component to separate into silicon fine particles and a second phase, and a step (c) of removing the second phase, The method for producing porous silicon particles, wherein in the step (b), the second phase is composed of an alloy of the Ti and the molten element and / or the molten element replaced with the Ti.
(19) An alloy of silicon, one or more intermediate alloy elements listed in Table 2, and one or more complex elements listed in Table 2, wherein the ratio of the complex elements is 1 to The maximum Si content in Table 2 corresponding to the intermediate alloy element contained is 33 atomic%, the silicon content is 10 atomic% or more with respect to the sum of the silicon, the intermediate alloy element, and the composite element. A step (a) for producing a silicon intermediate alloy having a content value or less, and a step of immersing in a molten metal of one or more molten elements shown in Table 2 corresponding to the intermediate alloy element to form silicon fine particles, silicon and a composite A step (b) for separating the body element silicon compound particles and the second phase, and a step (c) for removing the second phase, wherein the second phase comprises the intermediate alloy element and the second phase. An alloy of molten element and / or the molten element. Method for producing a porous silicon composite particles, characterized in that it is.
(20) In the step (a), silicon (X atom%), an intermediate alloy element (Y atom%), and one or more complex elements (Z 1 , Z 2 , Z 3 ,... Atom%) However, a silicon intermediate alloy having a composition satisfying the following formula is produced (the method for producing porous silicon composite particles according to 19).
10 ≦ X <[maximum Si content] Formula (1)
10 ≦ a ÷ (a + Y) × 100 ≦ [maximum Si content] Formula (2)
However, a = X−1.5 × (Z 1 + Z 2 + Z 3 ,...) [Maximum Si content] is the maximum Si content in Table 2 corresponding to the intermediate alloy element to be contained. is there.
(21) It is an alloy of silicon and one or more intermediate alloy elements described in Table 2, and the ratio of silicon is 10 atomic% or more of the total, and in Table 2 corresponding to the intermediate alloy element contained A step (a) for producing a silicon intermediate alloy having a maximum Si content of not more than the highest value, and a melt of one or more molten elements shown in Table 2 corresponding to the intermediate alloy element, One or more complex elements listed in Table 2 corresponding to the alloy elements are immersed in an alloy bath containing 10 atomic% or less and a total of 20 atomic% or less, and silicon fine particles, silicon compound particles of silicon and complex elements, A step (b) for separating the second phase and a step (c) for removing the second phase, wherein the second phase is an alloy of the intermediate alloy element and the molten element and / or It is composed of the molten metal element. Method for producing a porosifying silicon composite particles.
(22) In the step (a), the silicon intermediate alloy is in the form of a ribbon, foil or wire having a thickness of 0.1 μm to 2 mm, or in the form of a powder, granule or block having a particle size of 10 μm to 50 mm. (19) The method for producing porous silicon composite particles according to (19).
(23) In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is heated and reduced in pressure. The method for producing porous silicon composite particles according to (19), comprising a step of removing by evaporation.
(24) The step (a) is a step of producing a ribbon-like or thin-plate-like silicon intermediate alloy by using a single-roll casting machine or a twin-roll casting machine from the molten silicon, the intermediate alloy element, and the composite element. (19) The method for producing porous silicon composite particles according to (19).
(25) The step (a) is a step of producing a powdery silicon intermediate alloy by using an atomizing method of the molten silicon, the intermediate alloy element, and the composite element (19). ) For producing porous silicon composite particles.
(26) The step (a) includes a step of cooling a molten metal of the silicon, the intermediate alloy element, and the composite element in a mold to produce a lump silicon intermediate alloy ( The method for producing porous silicon composite particles according to 19).
(27) The ratio of silicon to Cu (Y atom%) is 10 to 30 atom% (X atom%) with respect to the whole, and As, Ba, Ca, Ce, Co, Cr, Er, Fe, Gd, Hf , Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb , One or more complex elements (Z 1 , Z 2 , Z 3 ,... Atomic%) selected from the group consisting of Zr so as to satisfy the formulas (1) and (2) of (20) A step (a) of forming a silicon intermediate alloy in a ribbon shape, foil piece shape, linear shape, or a powder size, granular shape, or a lump shape having a particle size of 10 μm to 50 mm with a thickness of 0.1 μm to 2 mm, and the silicon The intermediate alloy is made of at least one solution selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, and Zn. A step (b) of immersing in a molten metal containing hot metal as a main component to separate silicon fine particles, silicon and silicon compound particles of the complex element, and a second phase; and removing the second phase. (C), wherein the second phase is composed of an alloy of the Cu and the molten metal element and / or the molten metal element, and the step (c) includes the second phase as an acid, an alkali, Porous silicon composite particles characterized by comprising a step of dissolving and removing with at least one organic solvent, or a step of evaporating and removing only the second phase by heating and depressurizing Manufacturing method.
(28) Cu (Y atom%) is mixed with silicon in a proportion of 10 to 30 atom% (X atom%), with a thickness of 0.1 μm to 2 mm in ribbon, foil, or wire Or a step (a) of producing a granular / lumped silicon intermediate alloy having a particle size of 10 μm to 50 mm, and the silicon intermediate alloy is selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, Zn As a main component of the molten metal having one or more molten elements, As, Ba, Ca, Ce, Co, Cr, Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu , Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr, each of one or more complex elements Soaked in an alloy bath prepared by adding 10 atomic percent or less and a total of 20 atomic percent or less. A step (b) for separating silicon fine particles, silicon and silicon compound particles of the complex element, and a second phase, and a step (c) for removing the second phase, The second phase is composed of an alloy of the Cu and the molten element and / or the molten element, and the step (c) includes at least one of the acid, alkali, and organic solvent in the second phase. A method for producing porous silicon composite particles, comprising a step of dissolving and removing, or a step of evaporating and removing only the second phase by heating and decompressing.
(29) Mg (Y atom%) with a silicon content of 10 to 50 atom% (X atom%) with respect to the whole, As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf , Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb , One or more complex elements (Z 1 , Z 2 , Z 3 ,... Atomic%) selected from the group consisting of Zr so as to satisfy the formulas (1) and (2) of (20) A step (a) of forming a silicon intermediate alloy in a ribbon shape, foil piece shape, linear shape, or a powder size, granular shape, or a lump shape having a particle size of 10 μm to 50 mm with a thickness of 0.1 μm to 2 mm, and the silicon The intermediate alloy is made of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, Tl, Zn. A step of (b) separating the silicon fine particles, silicon and silicon compound particles of the composite element, and the second phase by immersing in a molten metal containing at least one molten element selected from the group as a main component; Removing the second phase (c), wherein the second phase is composed of an alloy of the Mg and the molten element and / or the molten element, and the step (c) includes the second step. A step of dissolving and removing the phase with at least one of an acid, an alkali and an organic solvent, or a step of evaporating and removing only the second phase by increasing the temperature and pressure. A method for producing porous silicon composite particles.
(30) Mg (Y atom%) is mixed with 10 to 50 atom% (X atom%) of silicon, and ribbons, foil pieces, and lines with a thickness of 0.1 μm to 2 mm Or a step (a) for producing a granular / lumped silicon intermediate alloy having a particle size of 10 μm to 50 mm, and the silicon intermediate alloy is made of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, As a main component of one or more molten metal elements selected from the group consisting of Tl and Zn, As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Ni , Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr. Add two or more complex elements for each 10 atomic percent or less, total 20 atomic percent or less A step (b) of immersing in the prepared alloy bath to separate silicon fine particles, silicon and silicon compound particles of the complex element, and a second phase; and a step (c) of removing the second phase. And the second phase is composed of an alloy of the Mg and the molten metal element and / or the molten metal element, and the step (c) includes the second phase of an acid, an alkali, or an organic solvent. A method for producing porous silicon composite particles, comprising: a step of dissolving and removing at least one or more, or a step of evaporating and removing only the second phase by heating and depressurizing. .
(31) Ni (Y atom%) is 10 to 55 atom% (Y atom%) relative to the whole, and As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf , Mn, Mo, Nb, Nd, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr One or more complex elements selected from the group consisting of (Z 1 , Z 2 , Z 3 ,... Atomic%) are blended so as to satisfy the formulas (1) and (2) of (20) (A) forming a ribbon-like, foil-like, linear or powdery / granular / lumped silicon intermediate alloy having a thickness of 0.1 μm to 2 mm, and the silicon intermediate alloy One or more molten elements selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, Zn A step (b) of immersing the substrate in a molten metal containing as a main component to separate silicon fine particles, silicon and silicon compound particles of the complex element, and a second phase; and removing the second phase (c) And the second phase is composed of the alloy of Ni and the molten metal element and / or the molten metal element, and the step (c) includes the second phase as an acid, an alkali, and an organic solvent. A step of dissolving and removing at least one or more, or a step of evaporating and removing only the second phase by raising the temperature and reducing the pressure. Method.
(32) Ni (Y atom%) is mixed with 10 to 55 atom% (Y atom%) of silicon in the whole, and ribbons, foil pieces, and lines with a thickness of 0.1 μm to 2 mm Or a step (a) of producing a granular / lumped silicon intermediate alloy having a particle size of 10 μm to 50 mm, and the silicon intermediate alloy is selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, Zn As a main component of the molten metal containing one or more molten elements, As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Os, Pr, Pt, Pu, Re 10 atoms each of one or more complex elements selected from the group consisting of Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr % Or less, soaked in an alloy bath created by adding up to 20 atomic% or less in total, A step (b) for separating silicon fine particles, silicon and silicon compound particles of the complex element, and a second phase; and a step (c) for removing the second phase, and the second phase. Is composed of an alloy of Ni and the molten element and / or the molten element, and the step (c) comprises dissolving the second phase with at least one of an acid, an alkali, and an organic solvent. A method for producing porous silicon composite particles, comprising a step of removing, or a step of evaporating and removing only the second phase by heating and decompressing.
(33) The proportion of silicon in Ti (Y atom%) is 10 to 80 atom% (Y atom%) with respect to the whole, and As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf , Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Tm, U, V, W, Y , Yb, Zr selected from the group consisting of one or more complex elements (Z 1 , Z 2 , Z 3 ,... Atomic%) satisfying the formulas (1) and (2) of (20) A step (a) of forming a silicon intermediate alloy in a ribbon shape, foil piece shape, linear shape having a thickness of 0.1 μm to 2 mm, or a powdery shape, granular shape, or a lump shape having a particle size of 10 μm to 50 mm; The silicon intermediate alloy is made of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, or Zn. A step (b) of immersing in a melt mainly composed of one or more melt elements selected from the group consisting of silicon fine particles, silicon and silicon compound particles of the composite element, and a second phase; And (c) removing the second phase, wherein the second phase is composed of the alloy of Ti and the molten element and / or the molten element, and the step (c) includes the step (c). A step of dissolving and removing the second phase with at least one of an acid, an alkali, and an organic solvent, or a step of evaporating and removing only the second phase by increasing the temperature and pressure. A method for producing porous silicon composite particles characterized by the above.
(34) Ti (Y atom%) is mixed with 10 to 80 atom% (Y atom%) of silicon, and ribbons, foil pieces, and wires with a thickness of 0.1 μm to 2 mm Or a step (a) of producing a granular / lumped silicon intermediate alloy having a particle size of 10 μm to 50 mm, and the silicon intermediate alloy is made of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, As a main component of one or more molten metal elements selected from the group consisting of Sn and Zn, As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb , Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Tm, U, V, W, Y, Yb, Zr One or more complex elements, each 10 atom% or less, total 20 atom% or less (B) a step of separating the silicon fine particles, silicon and silicon compound particles of the complex element, and a second phase by immersing in an alloy bath prepared by addition; and a step of removing the second phase ( c), wherein the second phase is composed of an alloy of Ti and the molten metal element and / or the molten metal element, and the step (c) includes the second phase as an acid, an alkali, and an organic material. A porous silicon composite particle comprising: a step of dissolving and removing at least one solvent in a solvent; or a step of evaporating and removing only the second phase by increasing the temperature and pressure. Production method.
　本発明により、高容量と良好なサイクル特性を実現するリチウムイオン電池用の負極材料などに好適な多孔質シリコン粒子及び多孔質シリコン複合体粒子を得ることができる。 According to the present invention, it is possible to obtain porous silicon particles and porous silicon composite particles suitable for a negative electrode material for a lithium ion battery that realizes a high capacity and good cycle characteristics.
（ａ）本発明にかかる多孔質シリコン粒子１を示す図、（ｂ）多孔質シリコン粒子１の表面近傍領域Ｓと粒子内部領域Ｉを示す図。(A) The figure which shows the porous silicon particle 1 concerning this invention, (b) The figure which shows the surface vicinity area | region S and the particle | grain internal area | region I of the porous silicon particle 1. FIG. （ａ）～（ｃ）多孔質シリコン粒子１の製造方法の概略を示す図。(A)-(c) The figure which shows the outline of the manufacturing method of the porous silicon particle 1. FIG. 本発明に係るリボン状シリコン中間合金の製造工程を説明する図。The figure explaining the manufacturing process of the ribbon-shaped silicon intermediate alloy which concerns on this invention. 本発明に係るリボン状シリコン中間合金の溶湯元素への浸漬工程を説明する図。The figure explaining the immersion process to the molten metal element of the ribbon-shaped silicon intermediate alloy which concerns on this invention. （ａ）本発明に係るガスアトマイズ装置３１を示す図、（ｂ）本発明にかかる回転円盤アトマイズ装置４１を示す図。(A) The figure which shows the gas atomizer 31 which concerns on this invention, (b) The figure which shows the rotary disk atomizer 41 concerning this invention. （ａ）～（ｃ）塊状シリコン中間合金の製造工程を説明する図。(A)-(c) The figure explaining the manufacturing process of a lump silicon intermediate alloy. （ａ）、（ｂ）本発明にかかる溶湯浸漬装置を示す図。(A), (b) The figure which shows the molten metal immersion apparatus concerning this invention. （ａ）本発明にかかる多孔質シリコン複合体粒子１０１を示す図、（ｂ）多孔質シリコン複合体粒子１０１の表面近傍領域Ｓと粒子内部領域Ｉを示す図。(A) The figure which shows the porous silicon composite particle 101 concerning this invention, (b) The figure which shows the surface vicinity area | region S and the particle | grain internal area | region I of the porous silicon composite particle 101. FIG. （ａ）～（ｃ）多孔質シリコン複合体粒子１０１の第１の製造方法の概略を示す図。FIGS. 5A to 5C are diagrams showing an outline of a first method for producing porous silicon composite particles 101. FIGS. （ａ）～（ｃ）多孔質シリコン複合体粒子１０１の第２の製造方法の概略を示す図。(A)-(c) The figure which shows the outline of the 2nd manufacturing method of the porous silicon composite particle 101. FIG. 実施例１－１２に係る多孔質シリコン粒子の表面のＳＥＭ写真。4 is an SEM photograph of the surface of porous silicon particles according to Example 1-12. 比較例１－１に係る多孔質シリコン粒子のＳＥＭ写真。4 is an SEM photograph of porous silicon particles according to Comparative Example 1-1. 実施例１－１２に係る多孔質シリコン粒子のＸ線回折格子像。2 is an X-ray diffraction grating image of porous silicon particles according to Example 1-12. 実施例２－１に係る多孔質シリコン複合体粒子の表面のＳＥＭ写真。4 is a SEM photograph of the surface of porous silicon composite particles according to Example 2-1. 実施例２－１に係る多孔質シリコン複合体粒子内部の断面のＳＥＭ写真。4 is an SEM photograph of a cross section inside the porous silicon composite particles according to Example 2-1. 実施例２－１に係る多孔質シリコン複合体粒子の表面のＳＥＭ写真。4 is a SEM photograph of the surface of porous silicon composite particles according to Example 2-1. 実施例２－１に係る多孔質シリコン複合体粒子のシリコン微粒子のＸ線回折格子像。X-ray diffraction grating image of silicon fine particles of porous silicon composite particles according to Example 2-1. 実施例２－１に係る多孔質シリコン複合体粒子のシリコン微粒子のＴＥＭ写真、制限視野電子線回折像（左上）。4 is a TEM photograph and a limited-field electron diffraction image (upper left) of silicon fine particles of porous silicon composite particles according to Example 2-1.
　［多孔質シリコン粒子］
　（多孔質シリコン粒子の構成）
　本発明に係る多孔質シリコン粒子１を、図１を参照して説明する。多孔質シリコン粒子１は、連続した空隙を有する三次元網目構造を有する多孔質体で、シリコン微粒子３が接合してなり、平均粒径が０．１μｍ～１０００μｍで、平均空隙率が１５～９３％である。また、多孔質シリコン粒子１は、酸素を除いた元素の比率でシリコンを８０原子％以上含み、残りは後述する中間合金元素、溶湯元素、その他の不可避な不純物が含まれている中実な粒子であることを特徴とする。 [Porous silicon particles]
(Configuration of porous silicon particles)
A porous silicon particle 1 according to the present invention will be described with reference to FIG. The porous silicon particle 1 is a porous body having a three-dimensional network structure having continuous voids, which is formed by bonding silicon fine particles 3, having an average particle size of 0.1 μm to 1000 μm, and an average porosity of 15 to 93. %. The porous silicon particles 1 contain 80 atomic% or more of silicon in the ratio of elements excluding oxygen, and the rest are solid particles containing intermediate alloy elements, molten metal elements, and other inevitable impurities described later. It is characterized by being.
　なお、このシリコン微粒子の表面に２０ｎｍ以下の酸化物層が形成されていても特性上問題ない。
　更に、シリコン微粒子の表面の酸化物層（酸化膜）は、塩酸等で第２相を除去した後に０．０００１～０．１Ｎの硝酸に浸漬することで形成することが出来る。もしくは、第２相を減圧蒸留で除去した後に、０．０００００００１～０．０２ＭＰａの酸素分圧下で保持することでも形成することができる。 Note that there is no problem in characteristics even if an oxide layer of 20 nm or less is formed on the surface of the silicon fine particles.
Further, the oxide layer (oxide film) on the surface of the silicon fine particles can be formed by immersing in 0.0001 to 0.1 N nitric acid after removing the second phase with hydrochloric acid or the like. Alternatively, it can also be formed by removing the second phase by distillation under reduced pressure and holding it under an oxygen partial pressure of 0.00000001 to 0.02 MPa.
　また、図１（ｂ）に示すように、多孔質シリコン粒子１を、半径方向で５０％以上の表面近傍領域Ｓと、半径方向で５０％以下の粒子内部領域Ｉとに分け、多孔質シリコン粒子の表面近傍領域を構成するシリコン微粒子の平均粒径をＤｓとし、多孔質シリコン粒子の粒子内部領域を構成するシリコン微粒子の平均粒径をＤｉとするとき、Ｄｓ／Ｄｉが０．５～１．５である。 Further, as shown in FIG. 1 (b), the porous silicon particles 1 are divided into a surface vicinity region S of 50% or more in the radial direction and a particle inner region I of 50% or less in the radial direction. When the average particle size of the silicon fine particles constituting the region near the surface of the particle is Ds and the average particle size of the silicon fine particles constituting the particle internal region of the porous silicon particle is Di, Ds / Di is 0.5 to 1 .5.
　また、多孔質シリコン粒子において、表面近傍領域Ｓの空隙率Ｘｓと、粒子内部領域Ｉの空隙率Ｘｉの比であるＸｓ／Ｘｉが０．５～１．５である。
　つまり、本発明にかかる多孔質シリコン粒子は、表面近傍領域と粒子内部領域とで、同様の細孔構造を有しており、粒子全体がほぼ均一な細孔構造を有する。 In the porous silicon particles, the ratio Xs / Xi, which is the ratio of the porosity Xs of the near-surface region S and the porosity Xi of the particle internal region I, is 0.5 to 1.5.
That is, the porous silicon particles according to the present invention have the same pore structure in the region near the surface and the region inside the particle, and the entire particle has a substantially uniform pore structure.
　多孔質シリコン粒子１を構成するシリコン微粒子３は、平均粒径または平均支柱径が２ｎｍ～２μｍ、結晶性を有する単結晶であり、酸素を除く元素の比率でシリコンを８０原子％以上含む中実な粒子であることを特徴とする。なお、ほぼ球形の微粒子が独立して存在していれば、粒径を測定することができるが、複数の微粒子が接合して、略柱状となっている場合には、長軸と垂直な断面での柱の直径に対応する平均支柱径を評価に用いる。 The silicon fine particles 3 constituting the porous silicon particles 1 are single crystals having an average particle diameter or average column diameter of 2 nm to 2 μm and having a crystallinity, and a solid containing 80 atomic% or more of silicon in a ratio of elements excluding oxygen. It is a characteristic particle. The particle diameter can be measured if substantially spherical fine particles exist independently, but when a plurality of fine particles are joined to form a substantially columnar shape, a cross section perpendicular to the long axis. The average strut diameter corresponding to the column diameter is used for evaluation.
　本発明での三次元網目構造は、スピノーダル分解過程で生じる共連続構造やスポンジ構造のような、空孔が互いに連接している構造を意味する。多孔質シリコン粒子が有する空孔は、空孔径が０．１～３００ｎｍ程度である。 The three-dimensional network structure in the present invention means a structure in which pores are connected to each other, such as a co-continuous structure or a sponge structure generated in the spinodal decomposition process. The pores of the porous silicon particles have a pore diameter of about 0.1 to 300 nm.
　シリコン微粒子３の平均粒径または平均支柱径は、２ｎｍ～２μｍであり、好ましくは１０～５００ｎｍ、より好ましくは、１５～１００ｎｍである。また、多孔質シリコン粒子１の平均空隙率は、１５～９３％であり、好ましくは３０～８０％であり、より好ましくは４０～７０％である。 The average particle diameter or the average column diameter of the silicon fine particles 3 is 2 nm to 2 μm, preferably 10 to 500 nm, more preferably 15 to 100 nm. The average porosity of the porous silicon particles 1 is 15 to 93%, preferably 30 to 80%, more preferably 40 to 70%.
　また、シリコン微粒子３どうしは、局所的に接合しており、シリコン微粒子３の接合部の面積が、前記シリコン微粒子の表面積の３０％以下である。つまり、シリコン微粒子３が独立して存在すると仮定して求められた表面積に比べて、多孔質シリコン粒子１の表面積は７０％以上である。 Further, the silicon fine particles 3 are locally bonded to each other, and the area of the bonded portion of the silicon fine particles 3 is 30% or less of the surface area of the silicon fine particles. That is, the surface area of the porous silicon particles 1 is 70% or more as compared with the surface area obtained on the assumption that the silicon fine particles 3 exist independently.
　本発明に係る多孔質シリコン粒子は通常は凝集して存在している。粒径の計測は、電子顕微鏡（ＳＥＭ）の画像情報と動的光散乱光度計（ＤＬＳ）の体積基準メディアン径を併用する。平均粒径は、ＳＥＭ画像によりあらかじめ粒子形状を確認し、画像解析ソフトウェア（例えば、旭化成エンジニアリング製「Ａ像くん」（登録商標））で粒径を求めたり、粒子を溶媒に分散してＤＬＳ（例えば、大塚電子製ＤＬＳ－８０００）により測定したりすることが可能である。ＤＬＳ測定時に粒子が十分に分散しており、凝集していなければ、ＳＥＭとＤＬＳでほぼ同じ測定結果が得られる。
　また、多孔質シリコン粒子を構成するシリコン微粒子は、互いに接合しているため、主に表面走査型電子顕微鏡や透過型電子顕微鏡を用いて平均粒径を求める。
　また、平均支柱径とは、アスペクト比が５以上の棒状（柱状）のシリコン粒子において、その柱の直径を支柱径と定義する。この支柱径の平均値を平均支柱径とする。この支柱径は、おもに粒子のＳＥＭ観察を行って求める。 The porous silicon particles according to the present invention are usually present in an aggregated state. The particle diameter is measured by using image information of an electron microscope (SEM) and a volume-based median diameter of a dynamic light scattering photometer (DLS). For the average particle size, the particle shape is confirmed in advance using an SEM image, the particle size is obtained using image analysis software (for example, “A Image-kun” (registered trademark) manufactured by Asahi Kasei Engineering), or DLS ( For example, it can be measured by DLS-8000 manufactured by Otsuka Electronics Co., Ltd. If the particles are sufficiently dispersed and not agglomerated at the time of DLS measurement, almost the same measurement results can be obtained with SEM and DLS.
Further, since the silicon fine particles constituting the porous silicon particles are bonded to each other, the average particle diameter is obtained mainly using a surface scanning electron microscope or a transmission electron microscope.
The average column diameter is defined as the column diameter of rod-shaped (columnar) silicon particles having an aspect ratio of 5 or more. Let the average value of this support | pillar diameter be an average support | pillar diameter. This strut diameter is obtained mainly by SEM observation of particles.
　平均空隙率は、粒子中の空隙の割合をいう。サブミクロン以下の細孔は窒素ガス吸着法によっても測定が可能であるが、細孔サイズが広範囲に渡る場合には、電子顕微鏡観察や、水銀圧入法（ＪＩＳ　Ｒ　１６５５「ファインセラミックスの水銀圧入法による成形体気孔径分布測定方法」、空隙内へ水銀を侵入させた際の圧力と水銀体積の関係から導出）、気体吸着法（ＪＩＳ　Ｚ　８８３０：２００１　気体吸着による粉体（固体）の比表面積測定方法）等により測定が可能である。 The average porosity means the ratio of voids in the particles. Submicron pores can be measured by nitrogen gas adsorption, but when the pore size is wide, observation with an electron microscope or mercury intrusion method (JIS R 1655 “fine mercury intrusion method of fine ceramics” Method of measuring the pore size distribution of compacts by using "Derived from the relationship between pressure and mercury volume when mercury enters the voids", Gas adsorption method (JIS Z 8830: 2001) Specific surface area of powder (solid) by gas adsorption Measurement is possible by measuring method).
　本発明に係る多孔質シリコン粒子１は、Ｓｉ中間合金のＳｉ濃度やその中間合金製造時の冷却速度により０．１μｍ～１０００μｍの平均粒径となる。なお、Ｓｉ濃度を低くする、もしくは冷却速度を早くすることで粒径は小さくなる。負極用活物質として使用する上では、その平均粒径が０．１～５０μｍであることが好ましく、より好ましくは１～３０μｍ、更に５～２０μｍであることが好ましい。そのために、多孔質シリコン粒子が小さい場合には凝集体または造粒体として使用される。また、多孔質シリコン粒子が大きい場合には、この多孔質シリコン粒子を粗に粉砕して使用しても何ら問題は無い。 The porous silicon particles 1 according to the present invention have an average particle diameter of 0.1 μm to 1000 μm depending on the Si concentration of the Si intermediate alloy and the cooling rate at the time of manufacturing the intermediate alloy. Note that the particle size is reduced by decreasing the Si concentration or increasing the cooling rate. When used as the negative electrode active material, the average particle diameter is preferably 0.1 to 50 μm, more preferably 1 to 30 μm, and further preferably 5 to 20 μm. Therefore, when the porous silicon particles are small, they are used as aggregates or granulated bodies. Further, when the porous silicon particles are large, there is no problem even if the porous silicon particles are roughly pulverized and used.
　（多孔質シリコン粒子の製造方法の概略）
　図２を用いて、多孔質シリコン粒子１の製造方法の概略を説明する。
　まず、図２（ａ）に示すように、シリコンと、中間合金元素を、加熱・溶融させ、シリコン中間合金７を作製する。
　その後、シリコン中間合金７を表１に記載の溶湯元素の溶湯に浸漬させる。この際、図２（ｂ）に示すように、シリコン中間合金７の中間合金元素が、溶湯中に溶出するなどして、主に溶湯元素からなる第２相９を形成し、シリコンのみがシリコン微粒子３として析出もしくは晶出する。第２相９は、中間合金元素と溶湯元素の合金であるか、中間合金元素と置換した溶湯元素で構成される。これらのシリコン微粒子３は、互いに接合し、三次元網目構造を形成する。
　その後、図２（ｃ）に示すように、酸やアルカリなどを用いた脱成分腐食などの方法により、第２相を除去すると、シリコン微粒子３が接合した多孔質シリコン粒子１が得られる。 (Outline of production method of porous silicon particles)
The outline of the manufacturing method of the porous silicon particle 1 is demonstrated using FIG.
First, as shown in FIG. 2A, silicon and an intermediate alloy element are heated and melted to produce a silicon intermediate alloy 7.
Thereafter, the silicon intermediate alloy 7 is immersed in a molten metal element shown in Table 1. At this time, as shown in FIG. 2B, the intermediate alloy element of the silicon intermediate alloy 7 is eluted into the molten metal to form the second phase 9 mainly composed of the molten element, and only silicon is silicon. Precipitate or crystallize as fine particles 3. The second phase 9 is an alloy of an intermediate alloy element and a molten element, or is composed of a molten element substituted for the intermediate alloy element. These silicon fine particles 3 are bonded to each other to form a three-dimensional network structure.
Thereafter, as shown in FIG. 2C, when the second phase is removed by a method such as decomponent corrosion using acid or alkali, porous silicon particles 1 to which silicon fine particles 3 are bonded are obtained.
　各工程での現象を説明する。シリコンと中間合金元素（Ｘ）を溶融、凝固すると、シリコンと中間合金元素の合金であるシリコン中間合金７が形成される。 Explain the phenomenon in each process. When silicon and the intermediate alloy element (X) are melted and solidified, a silicon intermediate alloy 7 which is an alloy of silicon and the intermediate alloy element is formed.
　その後、このシリコン中間合金を表１に規定される溶湯元素（Ｙ）浴に浸漬させると、溶湯元素（Ｙ）がシリコン中間合金中に拡散しながら浸透し、シリコン中間合金中の中間合金元素（Ｘ）は溶湯元素（Ｙ）と合金層を第２相として形成する。もしくは、合金中の中間合金元素（Ｘ）が溶湯元素（Ｙ）の金属浴中に溶出し、溶湯元素（Ｙ）が新たな第２相を形成する。この反応の中で、シリコン中間合金中に含まれていたシリコン原子が取り残される。その結果、このシリコン原子が、拡散した状態からナノサイズで凝集する際に、シリコン原子のネットワークができ、三次元網目構造が形成される。 Thereafter, when this silicon intermediate alloy is immersed in a molten element (Y) bath specified in Table 1, the molten element (Y) penetrates while diffusing into the silicon intermediate alloy, and the intermediate alloy element ( X) forms a molten element (Y) and an alloy layer as a second phase. Alternatively, the intermediate alloy element (X) in the alloy is eluted in the metal bath of the molten element (Y), and the molten element (Y) forms a new second phase. In this reaction, silicon atoms contained in the silicon intermediate alloy are left behind. As a result, when the silicon atoms are aggregated in a nano size from the diffused state, a network of silicon atoms is formed, and a three-dimensional network structure is formed.
　なお、中間合金中の合金でないシリコン初晶は、浸漬工程ではシリコン微粒子の析出に関係せず、また脱成分腐食などの第２相の除去にも関係せず、シリコンの初晶のまま残る。そのため、一度結晶になったシリコンは、粗大であり三次元網目構造を形成しない。そのため、シリコン中間合金を形成する工程において、シリコン合金中にシリコンの結晶が生じないことが好ましい。 In addition, the silicon primary crystal which is not an alloy in the intermediate alloy is not related to the precipitation of silicon fine particles in the dipping process and is not related to the removal of the second phase such as decomponent corrosion, and remains as the silicon primary crystal. Therefore, silicon once crystallized is coarse and does not form a three-dimensional network structure. Therefore, in the step of forming the silicon intermediate alloy, it is preferable that no silicon crystal is generated in the silicon alloy.
　以上の工程より、中間合金元素（Ｘ）と溶湯元素（Ｙ）には、以下の条件が必要となる。
・条件１：シリコンの融点より、溶湯元素（Ｙ）の融点が５０Ｋ以上低いこと。
　仮に溶湯元素（Ｙ）の融点とシリコンの融点が近いと、シリコン合金を溶湯元素の溶湯に浸漬する際、シリコンが溶湯中に溶解してしまうため、条件１が必要である。
・条件２：シリコンと中間合金元素を凝固させた際にＳｉ初晶が発生しないこと。
　シリコンと中間合金元素（Ｘ）の合金を形成する際に、シリコン濃度が増加する場合に過共晶領域になると粗大なシリコン初晶が形成される。このシリコン結晶は浸漬工程中での、シリコン原子の拡散・再凝集が生じず、三次元網目構造を形成しない。
・条件３：溶湯元素へのシリコンの溶解度が５原子％よりも低いこと。
　中間合金元素（Ｘ）と溶湯元素（Ｙ）が第２相を形成する際、シリコンを第２相に含まないようにする必要があるためである。
・条件４：中間合金元素と溶湯元素とが２相に分離しないこと。
　中間合金元素（Ｘ）と溶湯元素（Ｙ）が２相に分離してしまう場合、シリコン合金より中間合金元素が分離されず、シリコン原子の拡散・再凝集が生じない。さらには、酸による処理を行っても、シリコン粒子中に中間合金元素が残ってしまう。 From the above process, the following conditions are required for the intermediate alloy element (X) and the molten metal element (Y).
Condition 1: The melting point of the molten element (Y) is lower than the melting point of silicon by 50K or more.
If the melting point of the molten element (Y) is close to the melting point of silicon, condition 1 is necessary because silicon is dissolved in the molten metal when the silicon alloy is immersed in the molten molten element.
Condition 2: Si primary crystals do not occur when silicon and intermediate alloy elements are solidified.
When an alloy of silicon and intermediate alloy element (X) is formed, a coarse silicon primary crystal is formed when the hypereutectic region is reached when the silicon concentration increases. This silicon crystal does not cause diffusion or re-aggregation of silicon atoms during the dipping process, and does not form a three-dimensional network structure.
Condition 3: The solubility of silicon in the molten metal element is lower than 5 atomic%.
This is because when the intermediate alloy element (X) and the molten metal element (Y) form the second phase, it is necessary to prevent silicon from being included in the second phase.
Condition 4: The intermediate alloy element and the molten metal element do not separate into two phases.
When the intermediate alloy element (X) and the molten metal element (Y) are separated into two phases, the intermediate alloy element is not separated from the silicon alloy, and the silicon atoms do not diffuse and reaggregate. Furthermore, even if the treatment with an acid is performed, the intermediate alloy element remains in the silicon particles.
　以上の条件１～４を考慮すると、多孔質シリコン粒子を製造するために使用可能な中間合金元素と、溶湯元素の組み合わせは、以下のようになる。また、シリコンの割合が全体の１０原子％以上であり、中間合金元素に対応する下記表１中のＳｉ最大含有量の中で最も高い値以下である。 Considering the above conditions 1 to 4, the combinations of the intermediate alloy element and the molten metal element that can be used for producing the porous silicon particles are as follows. Moreover, the ratio of silicon is 10 atomic% or more of the whole, and is below the highest value among the maximum Si contents in Table 1 below corresponding to the intermediate alloy elements.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　中間合金元素としてＣｕを用いる場合は、Ｓｉと中間合金元素の和に対してＳｉの含有量は１０～３０原子％であり、得られた多孔質シリコン粒子の平均空隙率は４７～８５％である。 When Cu is used as the intermediate alloy element, the Si content is 10 to 30 atomic% with respect to the sum of Si and the intermediate alloy element, and the average porosity of the obtained porous silicon particles is 47 to 85%. is there.
　中間合金元素としてＭｇを用いる場合は、Ｓｉと中間合金元素の和に対してＳｉの含有量は１０～５０原子％であり、得られた多孔質シリコン粒子の平均空隙率は４２～９２％である。 When Mg is used as the intermediate alloy element, the Si content is 10 to 50 atomic% with respect to the sum of Si and the intermediate alloy element, and the average porosity of the obtained porous silicon particles is 42 to 92%. is there.
　中間合金元素としてＮｉを用いる場合は、Ｓｉと中間合金元素の和に対してＳｉの含有量は１０～５５原子％であり、得られた多孔質シリコン粒子の平均空隙率は１５～８５％である。 When Ni is used as the intermediate alloy element, the Si content is 10 to 55 atomic% with respect to the sum of Si and the intermediate alloy element, and the average porosity of the obtained porous silicon particles is 15 to 85%. is there.
　中間合金元素としてＴｉを用いる場合は、Ｓｉと中間合金元素の和に対してＳｉの含有量は１０～８２原子％であり、得られた多孔質シリコン粒子の平均空隙率は１５～８９％である。 When Ti is used as the intermediate alloy element, the Si content is 10 to 82 atomic% with respect to the sum of Si and the intermediate alloy element, and the average porosity of the obtained porous silicon particles is 15 to 89%. is there.
　なお、中間合金元素として、挙げられた元素を二つ以上使用することもできるが、その場合は溶湯元素としては、これらの中間合金元素のいずれにも対応する溶湯元素を使用する。 It should be noted that two or more of the listed elements can be used as the intermediate alloy element. In this case, the molten element corresponding to any of these intermediate alloy elements is used as the molten element.
　（多孔質シリコン粒子の製造方法）
　本発明に係る多孔質シリコン粒子の製造方法について説明する。
　まず、シリコンと、表１に記載のＡｓ，Ｂａ，Ｃａ，Ｃｅ，Ｃｏ，Ｃｒ，Ｃｕ，Ｅｒ，Ｆｅ，Ｇｄ，Ｈｆ，Ｌｕ，Ｍｇ，Ｍｎ，Ｍｏ，Ｎｂ，Ｎｄ，Ｎｉ，Ｐ，Ｐｄ，Ｐｒ，Ｐｔ，Ｐｕ，Ｒｅ，Ｒｈ，Ｒｕ，Ｓｃ，Ｓｍ，Ｓｒ，Ｔａ，Ｔｅ，Ｔｈ，Ｔｉ，Ｔｍ，Ｕ，Ｖ，Ｗ，Ｙ，Ｙｂ，Ｚｒからなる群より選ばれた一つ以上の中間合金元素を、シリコンの割合が全体の１０～９８原子％、好ましくは１５～５０原子％になるように配合した混合物を真空炉や非酸化性雰囲気炉などで加熱し、溶解する。その後、例えば、双ロール鋳造機での薄板連続鋳造や、図３に示すような単ロール鋳造機１１などを用いて、溶融したシリコン合金１３を、るつぼ１５より滴下し、図中矢印方向に回転する鋼製ロール１７に接しながら凝固させ線状またはリボン状のシリコン中間合金１９を製造する。なお、線状の母合金は、直接紡糸法で製造してもよい。または、シリコン中間合金を、線状やリボン状とは異なり、一定の長さを持つ箔片状としてもよい。 (Method for producing porous silicon particles)
A method for producing porous silicon particles according to the present invention will be described.
First, as shown in Table 1, As, Ba, Ca, Ce, Co, Cr, Cu, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, P, Pd, One or more selected from the group consisting of Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr A mixture in which the intermediate alloy element is blended so that the ratio of silicon is 10 to 98 atomic%, preferably 15 to 50 atomic%, is heated and melted in a vacuum furnace or a non-oxidizing atmosphere furnace. Thereafter, the molten silicon alloy 13 is dropped from the crucible 15 using, for example, continuous thin plate casting in a twin roll casting machine or a single roll casting machine 11 as shown in FIG. A solid or ribbon-like silicon intermediate alloy 19 is produced by solidifying the steel roll 17 while being in contact therewith. The linear mother alloy may be manufactured by a direct spinning method. Alternatively, the silicon intermediate alloy may be in the form of a foil piece having a certain length, unlike a linear shape or a ribbon shape.
　線状またはリボン状のシリコン中間合金１９の厚さは０．１μｍ～２ｍｍであることが好ましく、より好ましくは０．１～５００μｍであり、更に０．１～５０μｍであることが好ましい。シリコン中間合金の凝固時の冷却速度は０．１Ｋ／ｓ以上、好ましくは１００Ｋ／ｓ以上、より好ましくは４００Ｋ／ｓ以上である。これは凝固初期に生成する初晶の粒径を小さくすることで次工程での熱処理時間を短縮することに寄与するものである。また、この初晶の粒径が小さくなることで多孔質シリコン粒子の粒径も比例して小さくなる。なお、シリコン合金（中間合金）の厚みが２ｍｍ以上に厚くなると、Ｓｉ含有量が高い為に靭性に乏しく割れ・断線等が発生することから好ましくない。 The thickness of the linear or ribbon-like silicon intermediate alloy 19 is preferably 0.1 μm to 2 mm, more preferably 0.1 to 500 μm, and further preferably 0.1 to 50 μm. The cooling rate during solidification of the silicon intermediate alloy is 0.1 K / s or more, preferably 100 K / s or more, more preferably 400 K / s or more. This contributes to shortening the heat treatment time in the next step by reducing the grain size of the primary crystal formed in the initial stage of solidification. Further, the particle diameter of the porous silicon particles is reduced proportionally by reducing the particle diameter of the primary crystal. If the thickness of the silicon alloy (intermediate alloy) is 2 mm or more, it is not preferable because the Si content is high and the toughness is poor and cracks and disconnections occur.
　次に、シリコン中間合金を、使用した中間合金元素に対応する表１に記載のＡｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎから選択された溶湯元素の溶湯に浸漬させ、シリコンのスピノーダル分解（シリコン微粒子の析出）と中間合金元素と溶湯元素の合金である第２相もしくは中間合金元素と置換した前記溶湯元素で構成される第２相を形成させる。この浸漬工程で初めてＳｉ微粒子が形成される。浸漬工程は、例えば、図４に示すような溶湯浸漬装置２１を用い、リボン状シリコン中間合金１９を図中矢印方向に送り、溶湯元素の溶湯２３に浸漬する。その後、シンクロール２５やサポートロール２７を介して巻き取られる。溶湯２３は、溶湯元素の液相線温度より１０Ｋ以上高い温度に加熱してある。溶湯２３への浸漬は、溶湯温度にもよるが、５秒以上１００００秒以下であることが好ましい。１００００秒以上浸漬を施すと粗大なＳｉ粒が生成するためである。そして、これを非酸化性雰囲気下で冷却する。なお、後述のとおり、溶湯２３内に酸素が含まれない方が好ましい。 Next, the silicon intermediate alloy was selected from Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Tl, Zn listed in Table 1 corresponding to the intermediate alloy element used. A second phase composed of the molten metal element substituted by the spinodal decomposition of silicon (precipitation of silicon fine particles) and the second phase which is an alloy of the intermediate alloy element and the molten alloy element or the intermediate alloy element is immersed in the molten metal element. Let it form. Si fine particles are formed for the first time in this dipping process. In the dipping process, for example, using a molten metal dipping device 21 as shown in FIG. 4, the ribbon-shaped silicon intermediate alloy 19 is sent in the direction of the arrow in the drawing and dipped in the molten metal 23 of the molten element. Thereafter, the film is wound up via the sink roll 25 and the support roll 27. The molten metal 23 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more. Although immersion in the molten metal 23 depends on the molten metal temperature, it is preferably 5 seconds or more and 10,000 seconds or less. This is because coarse Si grains are produced when the immersion is performed for 10,000 seconds or more. Then, it is cooled in a non-oxidizing atmosphere. As described later, it is preferable that oxygen is not contained in the molten metal 23.
　その後、中間合金元素と溶湯元素の合金である第２相もしくは中間合金元素と置換した前記溶湯元素で構成される第２相を、酸、アルカリ、有機溶剤の少なくとも１つで溶解して除去する工程もしくは前記第２相を昇温減圧してその第２相のみを蒸発除去する工程により除去する。第２相が除去されることで、多孔質シリコン粒子が得られる。なお、酸としては、中間合金元素と溶湯元素を溶解させ、シリコンを溶解しない酸であればよく、硝酸、塩酸、硫酸などが挙げられる。 Thereafter, the second phase which is an alloy of the intermediate alloy element and the molten metal element or the second phase composed of the molten metal element replaced with the intermediate alloy element is dissolved and removed with at least one of an acid, an alkali and an organic solvent. The step or the second phase is heated and decompressed to remove only the second phase by evaporation. By removing the second phase, porous silicon particles are obtained. The acid may be any acid that dissolves the intermediate alloy element and the molten metal element and does not dissolve silicon, and examples thereof include nitric acid, hydrochloric acid, and sulfuric acid.
　酸、アルカリ、有機溶剤などで溶解する、もしくは昇温減圧蒸留することで第２相を除去した後は、微粒子で構成される多孔質シリコン粒子が得られる。酸、アルカリ、有機溶剤などで溶解した場合には、洗浄・乾燥を行う。シリコン中間合金のシリコン濃度や、シリコン中間合金製造時の冷却速度により０．１μｍ～１０００μｍの粒径となる。なお、シリコン濃度を低くする、もしくは冷却速度を早くすることで粒径は小さくなる。負極用活物質として使用する上では、その平均粒径が０．１～５０μｍであることが好ましく、より好ましくは１～３０μｍ、更に５～２０μｍであることが好ましい。その為に、多孔質シリコン粒子が小さい場合には、導電性を有する粘結剤を用いて凝集体または造粒体を作製し、スラリー状にして集電体に塗布して使用される。また、多孔質シリコン粒子が大きい場合には、この多孔質シリコン粒子を乳鉢等で粗に粉砕して使用しても何ら問題は無い。微粒子同士は局所的に接合しているので、簡便に破砕することが出来る。 After removing the second phase by dissolving with an acid, alkali, organic solvent, or the like, or by distillation at elevated temperature and reduced pressure, porous silicon particles composed of fine particles are obtained. If dissolved with acid, alkali, organic solvent, etc., wash and dry. Depending on the silicon concentration of the silicon intermediate alloy and the cooling rate at the time of manufacturing the silicon intermediate alloy, the particle diameter becomes 0.1 μm to 1000 μm. Note that the particle size is reduced by lowering the silicon concentration or increasing the cooling rate. When used as the negative electrode active material, the average particle diameter is preferably 0.1 to 50 μm, more preferably 1 to 30 μm, and further preferably 5 to 20 μm. Therefore, when the porous silicon particles are small, an aggregate or a granulated body is prepared using a conductive binder, and is used after being formed into a slurry and applied to a current collector. Further, when the porous silicon particles are large, there is no problem even if the porous silicon particles are roughly pulverized with a mortar or the like. Since the fine particles are locally joined, they can be easily crushed.
　（多孔質シリコン粒子の製造方法の他の例）
　多孔質シリコン複合体粒子１の製造方法の他の例として、線状やリボン状シリコン中間合金１９に代えて、粉末状、粒状、塊状のシリコン中間合金を用いても良い。
　まず、シリコンと、表１に記載のＡｓ，Ｂａ，Ｃａ，Ｃｅ，Ｃｏ，Ｃｒ，Ｃｕ，Ｅｒ，Ｆｅ，Ｇｄ，Ｈｆ，Ｌｕ，Ｍｇ，Ｍｎ，Ｍｏ，Ｎｂ，Ｎｄ，Ｎｉ，Ｐ，Ｐｄ，Ｐｒ，Ｐｔ，Ｐｕ，Ｒｅ，Ｒｈ，Ｒｕ，Ｓｃ，Ｓｍ，Ｓｒ，Ｔａ，Ｔｅ，Ｔｈ，Ｔｉ，Ｔｍ，Ｕ，Ｖ，Ｗ，Ｙ，Ｙｂ，Ｚｒからなる群より選ばれた一つ以上の中間合金元素を、シリコンの割合が全体の１０～９８原子％、好ましくは１５～５０原子％になるように配合した混合物を真空炉や非酸化性雰囲気炉などで加熱し、溶解する。その後、図５に示すようなアトマイズ法で粒・粉状のシリコン中間合金を製造する方法や、図６に示すインゴット製造法で塊状の鋳塊を得て、更に機械的な粉砕を行う方法で粒状シリコン中間合金を製造する。 (Another example of a method for producing porous silicon particles)
As another example of the method for producing the porous silicon composite particles 1, a powdery, granular, or massive silicon intermediate alloy may be used in place of the linear or ribbon-like silicon intermediate alloy 19.
First, as shown in Table 1, As, Ba, Ca, Ce, Co, Cr, Cu, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, P, Pd, One or more selected from the group consisting of Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr A mixture in which the intermediate alloy element is blended so that the ratio of silicon is 10 to 98 atomic%, preferably 15 to 50 atomic%, is heated and melted in a vacuum furnace or a non-oxidizing atmosphere furnace. Thereafter, a method of producing a grain / powder silicon intermediate alloy by the atomizing method as shown in FIG. 5 or a method of obtaining a massive ingot by the ingot production method shown in FIG. A granular silicon intermediate alloy is produced.
　図５（ａ）は、ガスアトマイズ法により粉末状シリコン中間合金３９を製造可能なガスアトマイズ装置３１を示す。るつぼ３３中には、誘導加熱などにより溶解したシリコンと中間合金元素のシリコン合金１３があり、このシリコン合金をノズル３５から滴下すると同時に、ガス噴射機３７からの不活性ガスのジェット流３８を吹き付けて、シリコン合金１３の溶湯を粉砕して、液滴として凝固させて粉末状シリコン中間合金３９を形成する。 FIG. 5 (a) shows a gas atomizing apparatus 31 capable of producing a powdered silicon intermediate alloy 39 by a gas atomizing method. In the crucible 33, there is silicon melted by induction heating or the like and a silicon alloy 13 of an intermediate alloy element. The silicon alloy is dropped from the nozzle 35 and at the same time, a jet stream 38 of inert gas from the gas injector 37 is blown. Then, the molten metal of the silicon alloy 13 is pulverized and solidified as droplets to form a powdery silicon intermediate alloy 39.
　図５（ｂ）は、回転円盤アトマイズ法により粉末状シリコン中間合金５１を製造可能な回転円盤アトマイズ装置４１を示す。るつぼ４３中には、溶解したシリコンと中間合金元素のシリコン合金１３があり、このシリコン合金をノズル４５から滴下させ、シリコン合金１３の溶湯を高速で回転する回転円盤４９上に落下させて、接線方向に剪断力を加えて破砕して粉末状シリコン中間合金５１を形成する。 FIG. 5B shows a rotating disk atomizing device 41 that can manufacture the powdered silicon intermediate alloy 51 by the rotating disk atomizing method. In the crucible 43, there is dissolved silicon and the silicon alloy 13 of the intermediate alloy element. This silicon alloy is dropped from the nozzle 45, and the molten metal of the silicon alloy 13 is dropped on the rotating disk 49 that rotates at high speed, thereby tangentially. A powdery silicon intermediate alloy 51 is formed by applying a shearing force in the direction and crushing.
　図６は、インゴット製造法により塊状シリコン中間合金５７を形成する工程を説明する図である。まず、シリコン合金１３の溶湯をるつぼ５３から鋳型５５に入れる。その後、鋳型５５内でシリコン合金１３が冷却され、固まった後に鋳型５５を除去して塊状シリコン中間合金５７が得られる。必要に応じて塊状シリコン中間合金５７を粉砕して、粒状シリコン中間合金が得られる。 FIG. 6 is a diagram illustrating a process of forming the massive silicon intermediate alloy 57 by the ingot manufacturing method. First, the molten silicon alloy 13 is put into the mold 55 from the crucible 53. Thereafter, the silicon alloy 13 is cooled in the mold 55 and solidified, and then the mold 55 is removed to obtain a bulk silicon intermediate alloy 57. If necessary, the bulk silicon intermediate alloy 57 is crushed to obtain a granular silicon intermediate alloy.
　粒状シリコン中間合金の厚さは１０μｍ～５０ｍｍであることが好ましく、より好ましくは０．１～１０ｍｍであり、更に１～５ｍｍであることが好ましい。シリコン合金の凝固時の冷却速度は０．１Ｋ／ｓ以上である。なお、シリコン中間合金の厚みが５０ｍｍ以上に厚くなると、熱処理時間が長くなることから多孔質シリコン粒子の粒径が成長し、粗大化することから好ましくない。その場合は、このシリコン中間合金に機械式粉砕を施し、５０ｍｍ以下にすることで対応できる。 The thickness of the granular silicon intermediate alloy is preferably 10 μm to 50 mm, more preferably 0.1 to 10 mm, and further preferably 1 to 5 mm. The cooling rate during solidification of the silicon alloy is 0.1 K / s or more. If the thickness of the silicon intermediate alloy is increased to 50 mm or more, the heat treatment time becomes longer, which is not preferable because the particle diameter of the porous silicon particles grows and becomes coarse. In that case, this silicon intermediate alloy can be dealt with by mechanically grinding it to 50 mm or less.
　次に、シリコン中間合金を、使用した中間合金元素に対応する表１に記載のＡｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎから選択された溶湯元素の溶湯に浸漬させ、シリコンのスピノーダル分解と中間合金元素と溶湯元素の合金である第２相を形成させる。なお、この溶湯中の酸素は予め１００ｐｐｍ以下、好ましくは１０ｐｐｍ以下、更に好ましくは２ｐｐｍ以下に低減しておくことが望ましい。これは溶湯中の溶存酸素とシリコンが反応してシリカを形成し、これを核としてシリコンがファセット状に成長し、粗大化する為である。その対策として、木炭・黒鉛などの固体還元材や非酸化性ガスにより還元することができるし、また酸素との親和力が強い元素を予め添加することでも良い。この浸漬工程で初めてシリコン微粒子が形成される。 Next, the silicon intermediate alloy was selected from Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Tl, Zn listed in Table 1 corresponding to the intermediate alloy element used. It is immersed in the molten metal element to form a spinodal decomposition of silicon and a second phase which is an alloy of the intermediate alloy element and the molten element element. The oxygen in the molten metal is desirably reduced in advance to 100 ppm or less, preferably 10 ppm or less, more preferably 2 ppm or less. This is because dissolved oxygen in the molten metal reacts with silicon to form silica, and with this as a nucleus, silicon grows in a facet shape and becomes coarse. As a countermeasure, it can be reduced by a solid reducing material such as charcoal / graphite or a non-oxidizing gas, or an element having a strong affinity for oxygen may be added in advance. Silicon particles are formed for the first time in this dipping process.
　浸漬工程は、図７（ａ）に示すような溶湯浸漬装置６１を用い、粒状シリコン中間合金６３を浸漬用籠６５に入れ、溶湯元素の溶湯６９に浸漬する。その際に、図７（ａ）に示すように、押し付けシリンダー６７を上下させて、シリコン中間合金もしくは溶湯へ機械式の振動を与えることや、超音波による振動を付与させること、図７（ｂ）に示す機械式撹拌機８１を用いた機械攪拌、ガス吹き込みプラグ８３を用いたガスインジェクションや電磁力を用いて溶湯を攪拌することで、短時間に反応を進めることができる。その後、非酸化性雰囲気下に引き上げられて冷却される。溶湯６９または７９は、溶湯元素の液相線温度より１０Ｋ以上高い温度に加熱してある。溶湯への浸漬は、溶湯温度にもよるが、５秒以上１００００秒以下であることが好ましい。１００００秒以上浸漬を施すと粗大Ｓｉ粒が生成するためである。 In the dipping step, a molten silicon immersion device 61 as shown in FIG. 7A is used, and the granular silicon intermediate alloy 63 is placed in a dipping bowl 65 and dipped in a molten metal 69 of a molten element. At that time, as shown in FIG. 7A, the pressing cylinder 67 is moved up and down to give mechanical vibration to the silicon intermediate alloy or molten metal, or to give vibration by ultrasonic waves, as shown in FIG. The reaction can be advanced in a short time by stirring the molten metal using mechanical stirring using the mechanical stirrer 81 and gas injection using the gas blowing plug 83 or electromagnetic force. Then, it is pulled up in a non-oxidizing atmosphere and cooled. The molten metal 69 or 79 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more. The immersion in the molten metal depends on the molten metal temperature, but is preferably 5 seconds or longer and 10,000 seconds or shorter. This is because coarse Si grains are produced when immersion is performed for 10,000 seconds or more.
　その後、前述の製造方法と同様に、第２相を除去し、多孔質シリコン粒子を得る。 Thereafter, the second phase is removed in the same manner as in the production method described above to obtain porous silicon particles.
　（多孔質シリコン粒子の効果）
　本発明によれば、従来にない３次元網目状構造を有する多孔質シリコン粒子を得ることができる。 (Effect of porous silicon particles)
According to the present invention, porous silicon particles having an unprecedented three-dimensional network structure can be obtained.
　本発明によれば、粒子の全体がほぼ均一な細孔構造を有する多孔質シリコン粒子を得ることができる。これは、溶湯内でのシリコン中間合金からのシリコン微粒子の析出は、高温の溶湯金属中で行うため、粒子内部まで溶湯金属が浸透するためである。 According to the present invention, porous silicon particles having a substantially uniform pore structure can be obtained. This is because precipitation of silicon fine particles from the silicon intermediate alloy in the molten metal is performed in the molten metal at a high temperature, so that the molten metal penetrates into the particles.
　本発明に係る多孔質シリコン粒子は、リチウムイオン電池の負極活物質として使用すれば、高容量で長寿命の負極を得ることができる。 When the porous silicon particles according to the present invention are used as a negative electrode active material of a lithium ion battery, a high capacity and long life negative electrode can be obtained.
　［多孔質シリコン複合体粒子］
　（多孔質シリコン複合体粒子の構成）
　本発明に係る多孔質シリコン複合体粒子を、図８を参照して説明する。図８（ａ）に示すように、本発明に係る多孔質シリコン複合体粒子１０１は、シリコン微粒子１０３とシリコン化合物粒子１０５が接合してなり、多孔質シリコン複合体粒子１０１の平均粒径が０．１μｍ～１０００μｍであり、多孔質シリコン複合体粒子１０１の平均空隙率が１５～９３％であり、連続した空隙からなる三次元網目構造を有する。 [Porous silicon composite particles]
(Configuration of porous silicon composite particles)
The porous silicon composite particles according to the present invention will be described with reference to FIG. As shown in FIG. 8A, the porous silicon composite particles 101 according to the present invention are formed by bonding silicon fine particles 103 and silicon compound particles 105, and the average particle size of the porous silicon composite particles 101 is zero. The average porosity of the porous silicon composite particles 101 is 15 to 93% and has a three-dimensional network structure composed of continuous voids.
　本発明での三次元網目構造は、スピノーダル分解過程で生じる共連続構造やスポンジ構造のような、空孔が互いに連接している構造を意味する。多孔質シリコン複合体粒子が有する空孔は、空孔径が０．１～３００ｎｍ程度である。 The three-dimensional network structure in the present invention means a structure in which pores are connected to each other, such as a co-continuous structure or a sponge structure generated in the spinodal decomposition process. The pores of the porous silicon composite particles have a pore diameter of about 0.1 to 300 nm.
　多孔質シリコン複合体粒子１０１において、半径方向で５０％以上の表面近傍領域の空隙率Ｘｓと、半径方向で５０％以内の粒子内部領域の空隙率Ｘｉの比であるＸｓ／Ｘｉが、０．５～１．５である。
　つまり、本発明にかかる多孔質シリコン複合体粒子は、表面近傍領域と粒子内部領域とで、同様の細孔構造を有しており、粒子全体がほぼ均一な細孔構造を有する。
　空隙率Ｘｓは、多孔質シリコン複合体粒子１０１の表面をＳＥＭ観察して求めることができ、空隙率Ｘｉは、多孔質シリコン複合体粒子１０１の断面の粒子内部領域に該当する箇所をＳＥＭ観察して求めることができる。 In the porous silicon composite particle 101, Xs / Xi, which is the ratio of the porosity Xs of the surface vicinity region of 50% or more in the radial direction and the porosity Xi of the particle internal region within 50% in the radial direction, is 0.00. 5 to 1.5.
That is, the porous silicon composite particles according to the present invention have the same pore structure in the surface vicinity region and the particle inner region, and the whole particle has a substantially uniform pore structure.
The porosity Xs can be obtained by SEM observation of the surface of the porous silicon composite particle 101, and the porosity Xi is obtained by observing a portion corresponding to the particle internal region in the cross section of the porous silicon composite particle 101 by SEM. Can be obtained.
　シリコン微粒子１０３は、平均粒径または平均支柱径が２ｎｍ～２μｍであり、好ましくは１０～５００ｎｍ、より好ましくは、２０～３００ｎｍである。また、平均空隙率は、１５～９３％であり、好ましくは５０～８０％であり、より好ましくは６０～７０％である。そして、一つ一つのシリコン微粒子１０３の結晶構造は、結晶性を有する単結晶である。また、シリコン微粒子１０３は、酸素を除く元素の比率でシリコンを８０原子％以上含み、残りは後述する中間合金元素、溶湯元素、その他の不可避な不純物が含まれる中実な微粒子である。 The silicon fine particles 103 have an average particle diameter or average column diameter of 2 nm to 2 μm, preferably 10 to 500 nm, and more preferably 20 to 300 nm. The average porosity is 15 to 93%, preferably 50 to 80%, more preferably 60 to 70%. The crystal structure of each silicon fine particle 103 is a single crystal having crystallinity. The silicon fine particles 103 contain 80 atomic% or more of silicon in a ratio of elements excluding oxygen, and the remainder are solid fine particles containing an intermediate alloy element, a molten metal element, and other inevitable impurities described later.
　また、図８（ｂ）に示すように、多孔質シリコン複合体粒子１０１を、半径方向で５０％以上の表面近傍領域Ｓと、半径方向で５０％以下の粒子内部領域Ｉとに分け、多孔質シリコン複合体粒子の表面近傍領域を構成するシリコン微粒子の平均粒径をＤｓとし、多孔質シリコン複合体粒子の粒子内部領域を構成するシリコン微粒子の平均粒径をＤｉとするとき、Ｄｓ／Ｄｉが０．５～１．５である。
　平均粒径Ｄｓは、多孔質シリコン複合体粒子１の表面をＳＥＭ観察して求めることができ、平均粒径Ｄｉは、多孔質シリコン複合体粒子１の粒子内部領域に該当する箇所の断面をＳＥＭ観察して求めることができる。 Further, as shown in FIG. 8 (b), the porous silicon composite particles 101 are divided into a surface vicinity region S of 50% or more in the radial direction and a particle inner region I of 50% or less in the radial direction. Ds / Di, where Ds is the average particle size of the silicon fine particles constituting the surface vicinity region of the porous silicon composite particles, and Di is the average particle size of the silicon fine particles constituting the particle inner region of the porous silicon composite particles Is 0.5 to 1.5.
The average particle diameter Ds can be obtained by observing the surface of the porous silicon composite particle 1 with an SEM, and the average particle diameter Di is obtained by SEM of a cross section of a portion corresponding to the particle internal region of the porous silicon composite particle 1. It can be obtained by observation.
　シリコン化合物粒子１０５は、平均粒径が５０ｎｍ～５０μｍであり、好ましくは１００ｎｍ～２０μｍ、より好ましくは、２００ｎｍ～１０μｍである。また、組成的には、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｏ、Ｃｒ、Ｃｕ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｌｕ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素と、５０～７５原子％のシリコンと後述する中間合金元素、溶湯元素、その他の不可避な不純物から構成されている中実な結晶性を有する粒子である。また、通常は、シリコン化合物粒子１０５は、シリコン微粒子１０３よりも大きい。 The silicon compound particles 105 have an average particle size of 50 nm to 50 μm, preferably 100 nm to 20 μm, and more preferably 200 nm to 10 μm. In terms of composition, As, Ba, Ca, Ce, Co, Cr, Cu, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu One or more complex elements selected from the group consisting of: Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr; It is a particle having solid crystallinity composed of 50 to 75 atomic% of silicon and an intermediate alloy element, a molten metal element, and other inevitable impurities described later. In general, the silicon compound particles 105 are larger than the silicon fine particles 103.
　また多孔質シリコン複合体粒子１０１の表面、すなわちシリコン微粒子１０３またはシリコン化合物粒子１０５には、厚さ２０ｎｍ以下、またはそれぞれのシリコン微粒子１０３またはシリコン化合物粒子１０５の粒径比で１０％以下の酸化物層が形成されていても特性上問題はない。
　多孔質シリコン複合体粒子１０１の表面の酸化物層は、第２相を除去した後に０．０００１～０．１Ｎの硝酸に浸漬することで形成することが出来る。もしくは、第２相を除去した後に、０．０００００００１～０．０２ＭＰａの酸素分圧下で保持することでも形成することができる。このシリコンなどの酸化物層が形成されると、多孔質シリコン複合体粒子１０１は、大気中でも極めて安定になり、グローブボックス等の中で取り扱われる必要がなくなる。 Further, the surface of the porous silicon composite particle 101, that is, the silicon fine particle 103 or the silicon compound particle 105 has an oxide having a thickness of 20 nm or less or a particle size ratio of the silicon fine particle 103 or the silicon compound particle 105 of 10% or less. Even if the layer is formed, there is no problem in characteristics.
The oxide layer on the surface of the porous silicon composite particles 101 can be formed by immersing in 0.0001 to 0.1 N nitric acid after removing the second phase. Alternatively, it can also be formed by holding under an oxygen partial pressure of 0.00000001 to 0.02 MPa after removing the second phase. When the oxide layer such as silicon is formed, the porous silicon composite particles 101 become extremely stable in the air and do not need to be handled in a glove box or the like.
　本発明に係る多孔質シリコン複合体粒子は通常は凝集して存在しているので、粒子の平均粒径は、ここでは一次粒子の平均粒径を指す。粒径の計測は、電子顕微鏡（ＳＥＭ）の画像情報と動的光散乱光度計（ＤＬＳ）の体積基準メディアン径を併用する。平均粒径は、ＳＥＭ画像によりあらかじめ粒子形状を確認し、画像解析ソフトウェア（例えば、旭化成エンジニアリング製「Ａ像くん」（登録商標））で粒径を求めたり、粒子を溶媒に分散してＤＬＳ（例えば、大塚電子製ＤＬＳ－８０００）により測定したりすることが可能である。ＤＬＳ測定時に粒子が十分に分散しており、凝集していなければ、ＳＥＭとＤＬＳでほぼ同じ測定結果が得られる。
　また、多孔質シリコン複合体粒子を構成するシリコン微粒子とシリコン化合物粒子は、互いに接合しているため、主に表面走査型電子顕微鏡や透過型電子顕微鏡を用いて平均粒径を求める。
　また、平均支柱径とは、アスペクト比が５以上の棒状（柱状）のシリコン粒子において、その柱の直径を支柱径と定義する。この支柱径の平均値を平均支柱径とする。この支柱径は、おもに粒子のＳＥＭ観察を行って求める。 Since the porous silicon composite particles according to the present invention are usually present in an aggregated state, the average particle size of the particles herein refers to the average particle size of the primary particles. The particle diameter is measured by using image information of an electron microscope (SEM) and a volume-based median diameter of a dynamic light scattering photometer (DLS). For the average particle size, the particle shape is confirmed in advance using an SEM image, the particle size is obtained using image analysis software (for example, “A Image-kun” (registered trademark) manufactured by Asahi Kasei Engineering), or DLS ( For example, it can be measured by DLS-8000 manufactured by Otsuka Electronics Co., Ltd. If the particles are sufficiently dispersed and not agglomerated at the time of DLS measurement, almost the same measurement results can be obtained with SEM and DLS.
Further, since the silicon fine particles and the silicon compound particles constituting the porous silicon composite particles are bonded to each other, the average particle size is obtained mainly using a surface scanning electron microscope or a transmission electron microscope.
The average column diameter is defined as the column diameter of rod-shaped (columnar) silicon particles having an aspect ratio of 5 or more. Let the average value of this support | pillar diameter be an average support | pillar diameter. This strut diameter is obtained mainly by SEM observation of particles.
　平均空隙率は、粒子中の空隙の割合をいう。サブミクロン以下の細孔は窒素ガス吸着法によっても測定可能であるが、細孔サイズが広範囲に渡る場合には、電子顕微鏡観察や、水銀圧入法（ＪＩＳ　Ｒ　１６５５「ファインセラミックスの水銀圧入法による成形体気孔径分布測定方法」、空隙内へ水銀を侵入させた際の圧力と水銀体積の関係から導出）、等により測定が可能である。また、ＢＥＴ比表面積は、窒素ガス吸着法によって測定可能である。 The average porosity means the ratio of voids in the particles. Submicron pores can be measured by nitrogen gas adsorption method, but when the pore size is wide, electron microscope observation or mercury intrusion method (JIS R 1655 “fine ceramics mercury intrusion method” It is possible to measure by, for example, “a method for measuring the pore size distribution of a molded body”, derived from the relationship between pressure and mercury volume when mercury enters the void). The BET specific surface area can be measured by a nitrogen gas adsorption method.
　本発明に係る多孔質シリコン複合体粒子１０１は、Ｓｉ中間合金のＳｉ濃度やその中間合金製造時の冷却速度により０．１μｍ～１０００μｍの粒径となる。なお、Ｓｉ濃度を低くする、もしくは冷却速度を早くすることで粒径は小さくなる。負極用活物質として使用する上では、その平均粒径が０．１～５０μｍであることが好ましく、より好ましくは１～３０μｍ、更に５～２０μｍであることが好ましい。その為に、多孔質シリコン複合体粒子が小さい場合には凝集体または造粒体として使用される。また、多孔質シリコン複合体粒子が大きい場合には、この多孔質シリコン複合体粒子を粗に粉砕して使用しても何ら問題は無い。 The porous silicon composite particles 101 according to the present invention have a particle size of 0.1 μm to 1000 μm depending on the Si concentration of the Si intermediate alloy and the cooling rate when manufacturing the intermediate alloy. Note that the particle size is reduced by decreasing the Si concentration or increasing the cooling rate. When used as the negative electrode active material, the average particle diameter is preferably 0.1 to 50 μm, more preferably 1 to 30 μm, and further preferably 5 to 20 μm. For this reason, when the porous silicon composite particles are small, they are used as aggregates or granules. Further, when the porous silicon composite particles are large, there is no problem even if the porous silicon composite particles are roughly pulverized and used.
　（多孔質シリコン複合体粒子の第１の製造方法の概略）
　図９を用いて、多孔質シリコン複合体粒子１０１の製造方法の概略を説明する。
　まず、図９（ａ）に示すように、シリコンと、中間合金元素と複合体元素とを、加熱・溶融させ、シリコン中間合金１０７を作製する。この際、シリコンと複合体元素と中間合金元素を溶融、凝固すると、シリコンと複合体元素と中間合金元素の中間合金１０７及び、シリコンと複合体元素からなるシリコン化合物粒子が形成される。 (Outline of first production method of porous silicon composite particles)
An outline of a method for producing the porous silicon composite particles 101 will be described with reference to FIG.
First, as shown in FIG. 9A, silicon, an intermediate alloy element, and a composite element are heated and melted to produce a silicon intermediate alloy 107. At this time, when silicon, the composite element, and the intermediate alloy element are melted and solidified, an intermediate alloy 107 of silicon, the composite element, and the intermediate alloy element, and silicon compound particles composed of silicon and the composite element are formed.
　その後、シリコン中間合金１０７を溶湯元素の溶湯に浸漬させる。シリコン中間合金１０７を溶融金属浴中に浸漬させると、溶湯元素がシリコン中間合金１０７中に浸透する。この際、中間合金元素は溶湯元素と合金固相を形成しながら、更に溶湯元素が浸透してくることで液相を形成する。この液相領域内にシリコン原子と複合体元素が残される。このシリコン原子や複合体元素が、拡散した状態から凝集する際に、シリコン微粒子１０３が析出し、シリコン原子と複合体元素の合金のネットワークができ、三次元網目構造が形成される。つまり、図９（ｂ）に示すように、シリコン中間合金１０７の中間合金元素が、溶湯中に溶出するなどして、第２相１０９を形成し、シリコンがシリコン微粒子１０３として析出する。第２相１０９は、中間合金元素と溶湯元素の合金であるか、中間合金元素と置換した溶湯元素で構成される。また、シリコン化合物粒子１０５は、溶湯元素の溶湯には影響されずにそのまま残る。これらのシリコン微粒子１０３、シリコン化合粒粒子１０５は、互いに接合し、三次元網目構造を形成する。 Thereafter, the silicon intermediate alloy 107 is immersed in the molten metal element. When the silicon intermediate alloy 107 is immersed in the molten metal bath, the molten metal element penetrates into the silicon intermediate alloy 107. At this time, the intermediate alloy element forms an alloy solid phase with the molten element, and further forms a liquid phase when the molten element permeates. Silicon atoms and complex elements are left in the liquid phase region. When the silicon atoms and the composite element are aggregated from the diffused state, the silicon fine particles 103 are precipitated, and an alloy network of silicon atoms and the composite element is formed, and a three-dimensional network structure is formed. That is, as shown in FIG. 9B, the intermediate alloy element of the silicon intermediate alloy 107 is eluted into the molten metal to form the second phase 109 and silicon is precipitated as silicon fine particles 103. The second phase 109 is an alloy of an intermediate alloy element and a molten element, or is composed of a molten element substituted for the intermediate alloy element. Further, the silicon compound particles 105 remain as they are without being influenced by the molten metal. These silicon fine particles 103 and silicon compound particles 105 are bonded to each other to form a three-dimensional network structure.
　なお、溶融金属浴への浸漬工程では、シリコン単独のシリコン初晶や、シリコンと複合体元素との化合物は、溶湯元素が浸透してきても、シリコン原子や複合体元素の再凝集を起こさず、シリコン初晶や複合体元素の化合物がそのまま残る。その為に、シリコン中間合金１０７の作製時の冷却速度を高めて、これらの粒径制御をすることが好ましい。 In the immersion process in the molten metal bath, the silicon primary crystal of silicon alone or the compound of silicon and the complex element does not cause reaggregation of the silicon atom or complex element even if the molten metal penetrates, The silicon primary crystal and the compound of the complex element remain as they are. For this purpose, it is preferable to control the particle size by increasing the cooling rate during the production of the silicon intermediate alloy 107.
　その後、図９（ｃ）に示すように、酸やアルカリなどを用いた脱成分腐食などの方法により、第２相１０９を除去すると、シリコン微粒子１０３とシリコン化合物粒子１０５が接合した多孔質シリコン複合体粒子１が得られる。 Thereafter, as shown in FIG. 9C, when the second phase 109 is removed by a method such as decomponent corrosion using acid or alkali, the porous silicon composite in which the silicon fine particles 103 and the silicon compound particles 105 are joined. Body particles 1 are obtained.
　以上の工程より、中間合金元素と複合体元素と溶湯元素には、以下の条件が必要となる。
・条件１：シリコンの融点より、溶湯元素の融点が５０Ｋ以上低いこと。
　仮に溶湯元素の融点とシリコンの融点が近いと、シリコン中間合金を溶湯元素の溶湯に浸漬する際、シリコンが溶湯中に溶解してしまうため、条件１が必要である。
・条件２：シリコンと中間合金元素を凝固させた際にＳｉ初晶が発生しないこと。
　シリコンと中間合金元素の合金を形成する際に、シリコン濃度が増加する場合に過共晶領域になると粗大なシリコン初晶が形成される。このシリコン初晶は浸漬工程中での、シリコン原子の拡散・再凝集が生じず、三次元網目構造を形成しない。
・条件３：溶湯元素へのシリコンの溶解度が５原子％よりも低いこと。
　中間合金元素と溶湯元素が第２相を形成する際、シリコンを第２相に含まないようにする必要があるためである。
・条件４：中間合金元素と溶湯元素とが２相に分離しないこと。
　中間合金元素と溶湯元素が２相に分離してしまう場合、シリコン中間合金より中間合金元素が分離されず、シリコン原子の拡散・再凝集が生じない。さらには、酸による処理を行っても、シリコン粒子中に中間合金元素が残ってしまう。 From the above steps, the following conditions are required for the intermediate alloy element, the composite element, and the molten metal element.
Condition 1: The melting point of the molten element is lower than the melting point of silicon by 50K or more.
If the melting point of the molten metal is close to the melting point of silicon, condition 1 is necessary because silicon is dissolved in the molten metal when the silicon intermediate alloy is immersed in the molten molten element.
Condition 2: Si primary crystals do not occur when silicon and intermediate alloy elements are solidified.
When forming an alloy of silicon and an intermediate alloy element, when the silicon concentration increases, a coarse silicon primary crystal is formed in the hypereutectic region. This silicon primary crystal does not cause diffusion or re-aggregation of silicon atoms during the dipping process, and does not form a three-dimensional network structure.
Condition 3: The solubility of silicon in the molten metal element is lower than 5 atomic%.
This is because when the intermediate alloy element and the molten metal element form the second phase, it is necessary not to include silicon in the second phase.
Condition 4: The intermediate alloy element and the molten metal element do not separate into two phases.
In the case where the intermediate alloy element and the molten metal element are separated into two phases, the intermediate alloy element is not separated from the silicon intermediate alloy, and diffusion / reaggregation of silicon atoms does not occur. Furthermore, even if the treatment with an acid is performed, the intermediate alloy element remains in the silicon particles.
・条件５：シリコンと複合体元素とが、２相に分離しないこと。
　シリコンと複合体元素が２相に分離しやすい場合、最終的にシリコンと複合体元素の合金からなるシリコン化合物粒子が得られない。
・条件６：溶湯元素に対応する中間合金元素は、選択可能な元素に複合体元素を含まないこと。
　複合体元素が、中間合金元素として選択可能な元素であり、前述のような中間合金元素の特徴を備える場合、溶湯元素と複合体元素が第２相を形成し、酸による処理を行う際に複合体元素が除去されてしまう。 Condition 5: Silicon and complex elements do not separate into two phases.
When the silicon and the composite element are easily separated into two phases, the silicon compound particles composed of an alloy of silicon and the composite element cannot be finally obtained.
Condition 6: The intermediate alloy element corresponding to the molten metal element does not include a complex element in the selectable elements.
When the composite element is an element that can be selected as an intermediate alloy element and has the characteristics of the intermediate alloy element as described above, when the molten metal element and the composite element form the second phase and the treatment with the acid is performed The complex element is removed.
　以上の条件１～６を考慮すると、多孔質シリコン複合体を製造するために使用可能な中間合金元素と、複合体元素と、溶湯元素の組み合わせ及び得られた多孔質シリコン複合体の空隙率は、以下のようになる。また、複合体元素の割合がシリコンの１～３３原子％である。さらに、シリコンの割合は、シリコンと中間合金元素と前記複合体元素の和に対して１０原子％以上であり、中間合金元素に対応する下記表２中のＳｉ最大含有量の値（複数の中間合金元素を含む場合は、それぞれの中間合金元素に対応する表２中のＳｉ最大含有量を、中間合金元素の割合に応じて案分した値）以下である。また、中間合金元素が複数含まれる場合には、それぞれの中間合金元素に共通して使用可能な複合体元素と溶湯元素を用いる。 Considering the above conditions 1 to 6, the combination of the intermediate alloy element, the composite element, and the molten metal element that can be used for producing the porous silicon composite and the porosity of the obtained porous silicon composite are: It becomes as follows. The ratio of the composite element is 1 to 33 atomic% of silicon. Furthermore, the ratio of silicon is 10 atomic% or more with respect to the sum of silicon, the intermediate alloy element, and the complex element, and the value of the maximum Si content in Table 2 below corresponding to the intermediate alloy element (a plurality of intermediate elements) In the case where the alloy element is included, the maximum Si content in Table 2 corresponding to each intermediate alloy element is a value that is prorated according to the ratio of the intermediate alloy element) or less. When a plurality of intermediate alloy elements are included, a composite element and a molten element that can be used in common with each intermediate alloy element are used.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　シリコン中間合金１０７を形成する工程において、シリコン（Ｘ原子％）と中間合金元素（Ｙ原子％）と１つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）が、以下の式を満足する組成を有するシリコン中間合金を作製することが好ましい。なお、［Ｓｉ最大含有量］は、中間合金元素に対応する前記表２中のＳｉ最大含有量の値であり、中間合金元素が複数ある場合は、各中間合金元素のＳｉ最大含有量を各中間合金元素の割合で案分した値である。また、中間合金元素が複数ある倍は、Ｙ原子％は、複数の中間合金元素の割合の和である。
　　１０≦Ｘ＜[Ｓｉ最大含有量]　　　　　　　　　　　　　　　　　（１）
　　１０≦ａ÷（ａ＋Ｙ）×１００≦[Ｓｉ最大含有量]　　　　　　　（２）
　　　　但し、ａ＝Ｘ－１．５×（Ｚ１+Ｚ２+Ｚ３、・・・・） In the step of forming the silicon intermediate alloy 107, silicon (X atom%), an intermediate alloy element (Y atom%), and one or more complex elements (Z 1 , Z 2 , Z 3 ,... Atom%) However, it is preferable to produce a silicon intermediate alloy having a composition satisfying the following formula. [Si maximum content] is the value of the maximum Si content in Table 2 corresponding to the intermediate alloy element. When there are a plurality of intermediate alloy elements, the maximum Si content of each intermediate alloy element is It is a value prorated according to the ratio of the intermediate alloy element. In addition, when there are a plurality of intermediate alloy elements, Y atomic% is the sum of the ratios of the plurality of intermediate alloy elements.
10 ≦ X <[maximum Si content] (1)
10 ≦ a ÷ (a + Y) × 100 ≦ [maximum Si content] (2)
However, a = X−1.5 × (Z 1 + Z 2 + Z 3 ,...)
　（多孔質シリコン複合体粒子の第１の製造方法）
　本発明に係る多孔質シリコン複合体粒子の製造方法について説明する。なお、以下では、多孔質シリコン粒子の製造方法で使用する装置を用いて説明し、各中間合金には同じ符号を付しているが、多孔質シリコン複合体粒子を製造するための中間合金は、複合体元素を含む点で、多孔質シリコン粒子を製造するための中間合金と異なる。 (First production method of porous silicon composite particles)
A method for producing porous silicon composite particles according to the present invention will be described. In the following, description will be made using an apparatus used in the method for producing porous silicon particles, and each intermediate alloy is denoted by the same reference numeral, but the intermediate alloy for producing porous silicon composite particles is This is different from the intermediate alloy for producing porous silicon particles in that it contains a composite element.
　まず、シリコンと、表２に記載のＣｏ，Ｃｒ，Ｃｕ，Ｆｅ，Ｍｇ，Ｍｎ，Ｍｏ，Ｎｉ，Ｐ，Ｔｉ，Ｚｒからなる群より選ばれた１以上の中間合金元素と、中間合金元素に対応する表２に記載の一つ以上の複合体元素を用い、シリコン、中間合金元素、複合体元素を配合した混合物を真空炉などで加熱し、溶解する。この際、シリコンと中間合金元素の合金と、シリコンと複合体元素の化合物が形成される。
　その後、例えば、図３に示すような単ロール鋳造機１１などを用いて、溶融したシリコン合金１３を、るつぼ１５より滴下し、回転する鋼製ロール１７に接しながら凝固させリボン状シリコン中間合金１９もしくは線状シリコン中間合金を製造する。シリコン中間合金の凝固時の冷却速度は１０Ｋ／ｓ以上、好ましくは１００Ｋ／ｓ以上、より好ましくは２００Ｋ／ｓ以上である。この冷却速度の高速化は、ミクロ組織的に凝固初期に生成するシリコン化合物粒子を小さくすることに寄与するものである。シリコン化合物粒子の大きさを細かくすることは、次工程での熱処理時間を短縮することに寄与するものである。リボン状シリコン中間合金１９もしくは線状のシリコン中間合金の厚さは０．１μｍ～２ｍｍであり、好ましくは０．１～５００μｍであり、更に０．１～５０μｍであることが好ましい。または、シリコン中間合金を、線状やリボン状とは異なり、一定の長さを持つ箔片状としてもよい。 First, silicon, one or more intermediate alloy elements selected from the group consisting of Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Ti, and Zr described in Table 2, and intermediate alloy elements Using a corresponding one or more composite elements shown in Table 2, a mixture containing silicon, intermediate alloy elements, and composite elements is heated and melted in a vacuum furnace or the like. At this time, an alloy of silicon and an intermediate alloy element and a compound of silicon and a complex element are formed.
Thereafter, for example, using a single roll casting machine 11 as shown in FIG. 3, the molten silicon alloy 13 is dropped from the crucible 15 and solidified while in contact with the rotating steel roll 17 to form a ribbon-like silicon intermediate alloy 19. Alternatively, a linear silicon intermediate alloy is manufactured. The cooling rate during solidification of the silicon intermediate alloy is 10 K / s or more, preferably 100 K / s or more, more preferably 200 K / s or more. This increase in the cooling rate contributes to reducing the size of silicon compound particles generated in the initial stage of solidification microscopically. Making the size of the silicon compound particles fine contributes to shortening the heat treatment time in the next step. The thickness of the ribbon-like silicon intermediate alloy 19 or the linear silicon intermediate alloy is 0.1 μm to 2 mm, preferably 0.1 to 500 μm, and more preferably 0.1 to 50 μm. Alternatively, the silicon intermediate alloy may be in the form of a foil piece having a certain length, unlike a linear shape or a ribbon shape.
　次に、シリコン中間合金を、表２に記載の中間合金元素に対応するＡｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎの少なくとも１つ以上から選択された溶湯元素の金属浴に浸漬させ、Ｓｉをスピノーダル分解させ、中間合金元素と溶湯元素の合金である第２相もしくは中間合金元素と置換した前記溶湯元素で構成される第２相を形成させる。浸漬工程は、例えば、図４に示すような溶湯浸漬装置２１を用い、リボン状シリコン中間合金１９もしくは線状シリコン中間合金を、溶湯元素の溶湯２３に浸漬する。その後、シンクロール２５やサポートロール２７を介して巻き取られる。溶湯２３は、溶湯元素の液相線温度より１０Ｋ以上高い温度に加熱してある。溶湯２３への浸漬は、溶湯温度にもよるが、５秒以上１００００秒以下であることが好ましい。１００００秒以上浸漬を施すと粗大Ｓｉ粒が生成するためである。浸漬後のリボン状シリコン中間合金１９を非酸化性雰囲気下で冷却し、シリコン微粒子１０３、シリコン化合物粒子１０５、第２相１０９の複合体を得る。 Next, the silicon intermediate alloy is made of at least one of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Tl, and Zn corresponding to the intermediate alloy elements described in Table 2. Submerged in a metal bath of a selected molten metal element, Si is spinodal decomposed to form a second phase that is an alloy of the intermediate alloy element and the molten element or a second phase composed of the molten element replaced with the intermediate alloy element Let In the dipping process, for example, a ribbon-like silicon intermediate alloy 19 or a linear silicon intermediate alloy is dipped in a molten metal 23 of a molten element using a molten metal immersion device 21 as shown in FIG. Thereafter, the film is wound up via the sink roll 25 and the support roll 27. The molten metal 23 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more. Although immersion in the molten metal 23 depends on the molten metal temperature, it is preferably 5 seconds or more and 10,000 seconds or less. This is because coarse Si grains are produced when immersion is performed for 10,000 seconds or more. The ribbon-like silicon intermediate alloy 19 after the immersion is cooled in a non-oxidizing atmosphere to obtain a composite of the silicon fine particles 103, the silicon compound particles 105, and the second phase 109.
　その後、中間合金元素と溶湯元素の合金である第２相１０９もしくは中間合金元素と置換した前記溶湯元素で構成される第２相１０９を、酸、アルカリ、有機溶剤の少なくとも１つ以上で溶解してその第２相１０９のみを取り除き洗浄・乾燥する。酸としては、中間合金元素と溶湯元素を溶解させ、シリコンを溶解しない酸であればよく、硝酸、塩酸、硫酸などが挙げられる。もしくはこの第２相１０９を昇温減圧してその第２相のみを蒸発除去することで除去する。 Thereafter, the second phase 109, which is an alloy of the intermediate alloy element and the molten element, or the second phase 109 composed of the molten element replaced with the intermediate alloy element is dissolved in at least one of an acid, an alkali, and an organic solvent. Then, only the second phase 109 is removed and washed and dried. The acid may be any acid that dissolves the intermediate alloy element and the molten metal element and does not dissolve silicon, and examples thereof include nitric acid, hydrochloric acid, and sulfuric acid. Alternatively, the second phase 109 is heated and decompressed to remove only the second phase by evaporation.
　なお、第２相１０９を除去した後は、多孔質シリコン複合体粒子１０１の粗大な凝集体が得られるので、ボールミルなどで粉砕し、凝集体の平均粒径が０．１μｍ～２０μｍになるようにする。 In addition, after removing the second phase 109, a coarse aggregate of the porous silicon composite particles 101 is obtained, so that the average particle diameter of the aggregate becomes 0.1 μm to 20 μm by pulverizing with a ball mill or the like. To.
　（多孔質シリコン複合体粒子１０１の第１の製造方法の他の例）
　多孔質シリコン複合体粒子１０１の第１の製造方法の他の例として、線状やリボン状シリコン中間合金１９に代えて、粉末状、粒状、塊状のシリコン中間合金を用いても良い。
　まず、シリコンと、表２に記載のＣｏ，Ｃｒ，Ｃｕ，Ｆｅ，Ｍｇ，Ｍｎ，Ｍｏ，Ｎｉ，Ｐ，Ｔｉ，Ｚｒからなる群より選ばれた１以上の中間合金元素と、中間合金元素に対応する表２に記載の１つ以上の複合体元素を用い、シリコン、中間合金元素、複合体元素を配合した混合物を真空炉などで加熱し、溶解する。
　その後、図５（ａ）、（ｂ）に示すようなアトマイズ法で略球状の粒・粉状のシリコン中間合金を製造する方法や、図６に示すインゴット製造法で塊状の鋳塊を得て、必要に応じて更に機械的な粉砕を行う方法で粉末状、粒状または塊状のシリコン中間合金を製造する。 (Another example of the first manufacturing method of the porous silicon composite particles 101)
As another example of the first method for producing the porous silicon composite particles 101, a silicon intermediate alloy in the form of a powder, a particle, or a lump may be used in place of the linear or ribbon-like silicon intermediate alloy 19.
First, silicon, one or more intermediate alloy elements selected from the group consisting of Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Ti, and Zr described in Table 2, and intermediate alloy elements Using a corresponding one or more composite elements shown in Table 2, a mixture containing silicon, intermediate alloy elements, and composite elements is heated and melted in a vacuum furnace or the like.
Thereafter, a massive ingot is obtained by a method of producing a substantially spherical grain / powdered silicon intermediate alloy by an atomizing method as shown in FIGS. 5A and 5B or by an ingot producing method shown in FIG. If necessary, a powdery, granular or massive silicon intermediate alloy is produced by a mechanical pulverization method.
　図５（ａ）は、ガスアトマイズ法により粉末状シリコン中間合金３９を製造可能なガスアトマイズ装置３１を示す。るつぼ３３中には、誘導加熱などにより溶解したシリコンと中間合金元素と複合体元素のシリコン合金１３があり、このシリコン合金１３をノズル３５から滴下すると同時に、不活性ガスや空気などの噴出ガス３６が供給されたガス噴射機３７からのガスジェット流３８を吹き付けて、シリコン合金１３の溶湯を粉砕して、液滴として凝固させて粉末状シリコン中間合金３９を形成する。 FIG. 5 (a) shows a gas atomizing apparatus 31 capable of producing a powdered silicon intermediate alloy 39 by a gas atomizing method. In the crucible 33, there is a silicon alloy 13 of silicon, an intermediate alloy element, and a composite element dissolved by induction heating or the like. The silicon alloy 13 is dropped from the nozzle 35 and at the same time, a jet gas 36 such as an inert gas or air is ejected. The gas jet flow 38 from the gas injector 37 supplied with is sprayed, the molten metal of the silicon alloy 13 is crushed and solidified as droplets to form a powdered silicon intermediate alloy 39.
　図５（ｂ）は、回転円盤アトマイズ法により粉末状シリコン中間合金５１を製造可能な回転円盤アトマイズ装置４１を示す。るつぼ４３中には、溶解したシリコンと中間合金元素と複合体元素のシリコン合金１３があり、このシリコン合金をノズル４５から滴下させ、シリコン合金１３の溶湯を高速で回転する回転円盤４９上に落下させて、接線方向に剪断力を加えて破砕して粉末状シリコン中間合金５１を形成する。 FIG. 5B shows a rotating disk atomizing device 41 that can manufacture the powdered silicon intermediate alloy 51 by the rotating disk atomizing method. In the crucible 43, there is a silicon alloy 13 of dissolved silicon, intermediate alloy element, and complex element. This silicon alloy is dropped from the nozzle 45, and the molten silicon alloy 13 is dropped onto a rotating disk 49 that rotates at high speed. Then, a shearing force is applied in the tangential direction to crush and form a powdery silicon intermediate alloy 51.
　図６は、インゴット製造法により塊状シリコン中間合金５７を形成する工程を説明する図である。まず、シリコン合金１３の溶湯をるつぼ５３から鋳型５５に入れる。その後、鋳型５５内でシリコン合金１３が冷却され、固まった後に鋳型５５を除去して塊状シリコン中間合金５７が得られる。塊状シリコン中間合金５７をそのまま用いても良いし、または必要に応じて粉砕して、粒状シリコン中間合金として用いても良い。 FIG. 6 is a diagram illustrating a process of forming the massive silicon intermediate alloy 57 by the ingot manufacturing method. First, the molten silicon alloy 13 is put into the mold 55 from the crucible 53. Thereafter, the silicon alloy 13 is cooled in the mold 55 and solidified, and then the mold 55 is removed to obtain a bulk silicon intermediate alloy 57. The bulk silicon intermediate alloy 57 may be used as it is, or may be pulverized as necessary and used as a granular silicon intermediate alloy.
　粉末状、粒状または塊状のシリコン中間合金の粒径は１０μｍ～５０ｍｍであることが好ましく、より好ましくは０．１～１０ｍｍであり、更に１～５ｍｍであることが好ましい。シリコン合金の凝固時の冷却速度は０．１Ｋ／ｓ以上である。なお、シリコン中間合金の厚みが５０ｍｍ以上に厚くなると、熱処理時間が長くなることから多孔質シリコン複合体粒子の粒径が成長し、粗大化することから好ましくない。その場合は、このシリコン中間合金に機械式粉砕を施し、厚みを５０ｍｍ以下にすることで対応できる。 The particle size of the powdery, granular or massive silicon intermediate alloy is preferably 10 μm to 50 mm, more preferably 0.1 to 10 mm, and further preferably 1 to 5 mm. The cooling rate during solidification of the silicon alloy is 0.1 K / s or more. If the thickness of the silicon intermediate alloy is increased to 50 mm or more, the heat treatment time becomes longer, which is not preferable because the particle diameter of the porous silicon composite particles grows and becomes coarse. In that case, the silicon intermediate alloy can be mechanically pulverized to reduce the thickness to 50 mm or less.
　次に、シリコン中間合金を、使用した中間合金元素に対応する表２に記載の溶湯元素の溶湯に浸漬させ、シリコンのスピノーダル分解と中間合金元素と溶湯元素の合金である第２相を形成させる。なお、この溶湯中の酸素は予め１００ｐｐｍ以下、好ましくは１０ｐｐｍ以下、更に好ましくは２ｐｐｍ以下に低減しておくことが望ましい。これは溶湯中の溶存酸素とシリコンが反応してシリカを形成し、これを核としてシリコンがファセット状に成長し、粗大化する為である。その対策として、木炭・黒鉛などの固体還元材や非酸化性ガスにより還元することができるし、また酸素との親和力が強い元素を予め添加することでも良い。この浸漬工程で初めてシリコン微粒子が形成される。 Next, the silicon intermediate alloy is immersed in the molten metal element shown in Table 2 corresponding to the used intermediate alloy element to form a spinodal decomposition of silicon and a second phase that is an alloy of the intermediate alloy element and the molten element. . The oxygen in the molten metal is desirably reduced in advance to 100 ppm or less, preferably 10 ppm or less, more preferably 2 ppm or less. This is because dissolved oxygen in the molten metal reacts with silicon to form silica, and with this as a nucleus, silicon grows in a facet shape and becomes coarse. As a countermeasure, it can be reduced by a solid reducing material such as charcoal / graphite or a non-oxidizing gas, or an element having a strong affinity for oxygen may be added in advance. Silicon particles are formed for the first time in this dipping process.
　浸漬工程は、図７（ａ）に示すような溶湯浸漬装置６１を用い、粒状シリコン中間合金６３を浸漬用籠６５に入れ、溶湯元素の溶湯６９に浸漬する。その際に、図７（ａ）に示すように、押し付けシリンダー６７を上下させて、シリコン中間合金もしくは溶湯へ機械式の振動を与えることや、超音波による振動を付与させること、図７（ｂ）に示す機械式撹拌機８１を用いた機械攪拌、ガス吹き込みプラグ８３を用いたガスインジェクションや電磁力を用いて溶湯を攪拌することで、短時間に反応を進めることができる。その後、非酸化性雰囲気下に引き上げられて冷却される。溶湯６９または７９は、溶湯元素の液相線温度より１０Ｋ以上高い温度に加熱してある。溶湯への浸漬は、溶湯温度にもよるが、５秒以上１００００秒以下であることが好ましい。１００００秒以上浸漬を施すと粗大Ｓｉ粒が生成するためである。なお、シリコン中間合金の前述の粉末状、粒状、塊状という形状は、アスペクト比の小さい形状（アスペクト比５以下）のシリコン中間合金を、大きさにより、粉末、粒、塊と呼んでいるだけで、厳密に定義するわけではない。また、粒状シリコン中間合金６３，７３，９３については、前述の粉末状、粒状、塊状シリコン中間合金を代表して粒状シリコン中間合金と表記している。 In the dipping step, a molten silicon immersion device 61 as shown in FIG. 7A is used, and the granular silicon intermediate alloy 63 is placed in a dipping bowl 65 and dipped in a molten metal 69 of a molten element. At that time, as shown in FIG. 7A, the pressing cylinder 67 is moved up and down to give mechanical vibration to the silicon intermediate alloy or molten metal, or to give vibration by ultrasonic waves, as shown in FIG. The reaction can be advanced in a short time by stirring the molten metal using mechanical stirring using the mechanical stirrer 81 and gas injection using the gas blowing plug 83 or electromagnetic force. Then, it is pulled up in a non-oxidizing atmosphere and cooled. The molten metal 69 or 79 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more. The immersion in the molten metal depends on the molten metal temperature, but is preferably 5 seconds or longer and 10,000 seconds or shorter. This is because coarse Si grains are produced when immersion is performed for 10,000 seconds or more. The above-mentioned powdery, granular, and lump shapes of silicon intermediate alloys are simply called silicon powders, particles, and lumps with a small aspect ratio (aspect ratio of 5 or less) depending on the size. It is not strictly defined. Further, the granular silicon intermediate alloys 63, 73, and 93 are represented as granular silicon intermediate alloys on behalf of the aforementioned powdery, granular, and massive silicon intermediate alloys.
　その後、前述の製造方法と同様に、第２相を除去し、多孔質シリコン複合体粒子を得る。 Thereafter, in the same manner as in the production method described above, the second phase is removed to obtain porous silicon composite particles.
　（多孔質シリコン複合体粒子の第２の製造方法）
　本発明に係る多孔質シリコン複合体粒子の第２の製造方法について説明する。第２の製造方法では、図１０（ａ）に示すように、シリコンと中間合金元素からなるシリコン中間合金１１１を形成する。その後、溶湯元素に複合体元素を加えた溶湯に浸漬させることで、図１０（ｂ）に示すように、シリコン微粒子１０３とシリコン化合物粒子１０５と第２相１０９を形成する。その後、図１０（ｃ）に示すように、第２相１０９を除去して多孔質シリコン複合体粒子１０１を得る。 (Second production method of porous silicon composite particles)
The second method for producing porous silicon composite particles according to the present invention will be described. In the second manufacturing method, as shown in FIG. 10A, a silicon intermediate alloy 111 made of silicon and an intermediate alloy element is formed. Thereafter, the silicon fine particles 103, the silicon compound particles 105, and the second phase 109 are formed as shown in FIG. 10B by immersing in a molten metal obtained by adding a complex element to the molten metal element. Thereafter, as shown in FIG. 10C, the second phase 109 is removed to obtain porous silicon composite particles 101.
　以下、第２の製造方法を具体的に説明する。
　まず、シリコンの粉末と、表２に記載のＣｏ，Ｃｒ，Ｃｕ，Ｆｅ，Ｍｇ，Ｍｎ，Ｍｏ，Ｎｉ，Ｐ，Ｔｉ，Ｚｒからなる群より選ばれた１以上の中間合金元素の粉末とを、シリコン（Ｘ原子％）、中間合金元素（Ｙ原子％）を式（３）を満足するように溶解する。
　　Ｘ÷（Ｘ＋Ｙ）×１００≦[Ｓｉ最大含有量]　　　　　　　　　（３） Hereinafter, the second manufacturing method will be specifically described.
First, silicon powder and one or more intermediate alloy element powders selected from the group consisting of Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Ti, and Zr listed in Table 2 are used. Silicon (X atomic%) and intermediate alloy element (Y atomic%) are dissolved so as to satisfy the formula (3).
X ÷ (X + Y) × 100 ≦ [maximum Si content] (3)
　その後、第１の製造方法と同様に、図３に示すような単ロール鋳造機１１などを用いて、シリコンと中間合金元素の合金である、リボン状シリコン中間合金１９もしくは線状シリコン中間合金を製造する。もしくは、図５（ａ）、（ｂ）に示すようなアトマイズ法によって粉末状シリコン中間合金を製造する。また、図６に示すようにシリコン中間合金をインゴット鋳造し、これを機械的に粉砕して粒状にしてもよい。 Thereafter, similarly to the first manufacturing method, a ribbon-like silicon intermediate alloy 19 or a linear silicon intermediate alloy, which is an alloy of silicon and an intermediate alloy element, is used by using a single roll casting machine 11 as shown in FIG. To manufacture. Alternatively, a powdery silicon intermediate alloy is manufactured by an atomizing method as shown in FIGS. Further, as shown in FIG. 6, a silicon intermediate alloy may be cast into an ingot, which may be mechanically pulverized into a granular shape.
　次に、シリコン中間合金を、表２に記載の中間合金元素に対応するＡｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎの少なくとも１つ以上の溶湯元素に、表２に記載の中間合金元素に対応する一つ以上の複合体元素を各々１０原子％以下、合計で２０原子％以下添加し作製された合金浴へ浸漬させ、Ｓｉのスピノーダル分解と、Ｓｉと複合体元素との化合物の形成と、中間合金元素と溶湯元素の合金である第２相及び／または中間合金元素と置換した前記溶湯元素で構成される第２相を形成させる。浸漬工程は、図４に示すような溶湯浸漬装置２１を用い、リボン状シリコン中間合金１９もしくは線状シリコン中間合金を、溶湯元素の溶湯２３に浸漬するか、図７に示すような溶湯浸漬装置または溶湯処理装置を用い、粒状シリコン中間合金を、溶湯元素の溶湯に浸漬する。溶湯２３は、溶湯元素の液相線温度より１０Ｋ以上高い温度に加熱してある。溶湯２３への浸漬は、溶湯温度にもよるが、５秒以上１００００秒以下であることが好ましい。１００００秒以上浸漬を施すと粗大Ｓｉ粒が生成するためである。これを非酸化性雰囲気下で冷却し、シリコン微粒子１０３、シリコン化合物粒子１０５、第２相１０９の複合体を得る。 Next, the silicon intermediate alloy is made of at least one of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Tl, and Zn corresponding to the intermediate alloy elements described in Table 2. One or more complex elements corresponding to the intermediate alloy elements listed in Table 2 are added to the molten metal element in an amount of 10 atomic% or less, and a total of 20 atomic% or less, respectively. And forming a compound of Si and a composite element, and forming a second phase that is an alloy of an intermediate alloy element and a molten metal element and / or a second phase composed of the molten metal element replaced with the intermediate alloy element. The dipping process uses a molten metal dipping device 21 as shown in FIG. 4 to immerse the ribbon-like silicon intermediate alloy 19 or the linear silicon intermediate alloy in the molten metal 23 of the molten element, or as shown in FIG. Alternatively, the molten silicon processing apparatus is used to immerse the granular silicon intermediate alloy in the molten metal element. The molten metal 23 is heated to a temperature higher than the liquidus temperature of the molten element by 10K or more. Although immersion in the molten metal 23 depends on the molten metal temperature, it is preferably 5 seconds or more and 10,000 seconds or less. This is because coarse Si grains are produced when immersion is performed for 10,000 seconds or more. This is cooled in a non-oxidizing atmosphere to obtain a composite of silicon fine particles 103, silicon compound particles 105, and second phase 109.
　なお、このシリコン中間合金を、中間合金元素に対応する表２に記載の溶湯元素の浴に浸漬させた後に、中間合金元素に対応する表２に記載の溶湯元素に、中間合金元素に対応する表２に記載の複合体元素からなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作製された合金浴に浸漬させてもよい。 In addition, after immersing this silicon intermediate alloy in the bath of the molten element shown in Table 2 corresponding to the intermediate alloy element, the molten element shown in Table 2 corresponding to the intermediate alloy element corresponds to the intermediate alloy element. One or more complex elements selected from the group consisting of the complex elements shown in Table 2 may be added to each of 10 atomic% or less and a total of 20 atomic% or less to be immersed in an alloy bath.
　その後、前述の第１の製造方法と同様に第２相１０９のみを除去して、多孔質シリコン複合体粒子１０１を得る。 Thereafter, only the second phase 109 is removed in the same manner as in the first manufacturing method described above to obtain porous silicon composite particles 101.
　（多孔質シリコン複合体粒子の効果）
　本発明によれば、従来にない３次元網目状構造を有する多孔質シリコン複合体粒子を得ることができる。 (Effect of porous silicon composite particles)
According to the present invention, porous silicon composite particles having an unprecedented three-dimensional network structure can be obtained.
　本発明によれば、粒子の全体がほぼ均一な細孔構造を有する多孔質シリコン複合体粒子を得ることができる。これは、溶湯内でのシリコン中間合金からのシリコン微粒子の析出は、高温の溶湯金属中で行うため、粒子内部まで溶湯金属が浸透するためである。 According to the present invention, porous silicon composite particles having a substantially uniform pore structure as a whole can be obtained. This is because precipitation of silicon fine particles from the silicon intermediate alloy in the molten metal is performed in the molten metal at a high temperature, so that the molten metal penetrates into the particles.
　本発明に係る多孔質シリコン複合体粒子は、リチウムイオン電池の負極活物質として使用すれば、高容量で長寿命の負極を得ることができる。特に、複合体元素は、シリコンに比べてリチウムを吸蔵しにくい元素であるため、リチウムイオンの吸蔵時に複合体元素は膨張し難いため、シリコンの膨張が抑制され、より長寿命の負極を得ることができる。また、シリコンと複合体元素との化合物であるシリコン化合物粒子は、シリコンに比べて導電性が高いため、本発明に係る多孔質シリコン複合体粒子は、通常のシリコン粒子に比べて急速な充放電に対応できる。 When the porous silicon composite particles according to the present invention are used as a negative electrode active material of a lithium ion battery, a negative electrode having a high capacity and a long life can be obtained. In particular, since the complex element is an element that does not absorb lithium as much as silicon, the complex element is difficult to expand during storage of lithium ions, so that expansion of silicon is suppressed and a longer-life negative electrode is obtained. Can do. In addition, since silicon compound particles, which are compounds of silicon and a composite element, have higher conductivity than silicon, the porous silicon composite particles according to the present invention are more rapidly charged / discharged than normal silicon particles. It can correspond to.
　以下、本発明について実施例および比較例を用いて具体的に説明する。実施例１－１～１－１６が、シリコン多孔質粒子に関する実施例であり、実施例２－１～２－１６が、複合体元素を含む多孔質シリコン複合体粒子に関する実施例である。
　［実施例１］
　（実施例１－１）
　Ｓｉ：Ｃｏ＝５５：４５（原子％）の割合でシリコン（塊状、純度：９５．０％以上）とコバルトを配合し、これを真空炉中にて１４８０℃で溶解した。その後、単ロール鋳造機を用いて冷却速度：８００Ｋ／ｓで急冷し板厚２００μｍのシリコン合金製リボンを作製した。これを９４０℃のスズ溶湯に１分浸漬させた後に、直ちにアルゴンガスにて急冷した。この処理により、Ｓｉと、Ｃｏ－ＳｎまたはＳｎからなる第２相の２相複合体が得られた。この２相複合体を硝酸２０％水溶液中に５分浸漬させ、多孔質シリコン粒子を得た。 Hereinafter, the present invention will be specifically described using examples and comparative examples. Examples 1-1 to 1-16 are examples relating to silicon porous particles, and Examples 2-1 to 2-16 are examples relating to porous silicon composite particles containing a composite element.
[Example 1]
Example 1-1
Silicon (lumpy, purity: 95.0% or more) and cobalt were blended at a ratio of Si: Co = 55: 45 (atomic%), and dissolved at 1480 ° C. in a vacuum furnace. Thereafter, the ribbon was rapidly cooled using a single roll casting machine at a cooling rate of 800 K / s to produce a silicon alloy ribbon having a thickness of 200 μm. This was immersed in molten tin at 940 ° C. for 1 minute, and then immediately quenched with argon gas. By this treatment, a two-phase composite composed of Si and Co—Sn or Sn was obtained. This two-phase composite was immersed in a 20% nitric acid aqueous solution for 5 minutes to obtain porous silicon particles.
　（実施例１－２～１－１１）
　各実施例、比較例の製造条件を、表３にまとめた。実施例１－２～１－１１は、表３に示す中間合金元素、各元素の配合比率、などの製造条件にて、他は実施例１－１の方法と同様にして多孔質シリコン複合体を得た。 (Examples 1-2 to 1-11)
The production conditions for each example and comparative example are summarized in Table 3. In Examples 1-2 to 1-11, porous silicon composites were produced in the same manner as in Example 1-1, except for the production conditions such as the intermediate alloy elements shown in Table 3 and the blending ratio of each element. Got.
　（実施例１－１２）
　Ｓｉ：Ｍｇ＝１２：８８（原子％）の割合でシリコン（塊状、純度：９５．０％以上）とマグネシウムを配合し、これを真空炉内をアルゴンガス置換した状態で、１０９０℃で溶解した。その後、鋳型へ鋳込み凝固させた後に、機械的に粉砕し５ｍｍ角の大きさのシリコン合金製インゴットを作製した。これを４７０℃の鉛溶湯に３０分浸漬させた後に、直ちにアルゴンガスにて急冷した。この処理によりＳｉと、Ｍｇ－ＰｂまたはＰｂからなる第２相の２相複合体が得られた。この２相複合体を硝酸２０％水溶液中に１８０分浸漬させ、多孔質シリコン粒子を得た。 (Example 1-12)
Si (Mass, purity: 95.0% or more) and magnesium were blended at a ratio of Si: Mg = 12: 88 (atomic%), and this was melted at 1090 ° C. in a state where the inside of the vacuum furnace was replaced with argon gas. . Then, after casting into a mold and solidifying, it was mechanically pulverized to produce a silicon alloy ingot having a size of 5 mm square. This was immersed in a molten lead at 470 ° C. for 30 minutes and then immediately cooled with argon gas. By this treatment, a two-phase composite composed of Si and Mg—Pb or Pb was obtained. This two-phase composite was immersed in a 20% nitric acid aqueous solution for 180 minutes to obtain porous silicon particles.
　（実施例１－１３～１－１６）
　実施例１－１３～１－１６は、表３に示す中間合金元素、各元素の配合比率、などの製造条件にて、他は実施例１－１２の方法と同様にして多孔質シリコン複合体を得た。 (Examples 1-13 to 1-16)
In Examples 1-13 to 1-16, porous silicon composites were produced in the same manner as in Example 1-12, except for the production conditions such as the intermediate alloy elements shown in Table 3 and the blending ratio of each element. Got.
　（比較例１－１）
　Ｓｉ：Ｍｇ＝５５：４５（原子％）の割合でシリコン粉末とマグネシウム粉末を配合し、これをアルゴン雰囲気中にて１０８７℃で溶解した。その後、双ロール鋳造機を用いて冷却速度：２００Ｋ／ｓで板厚１ｍｍのシリコン合金製テープを作製した。これを５００℃のビスマス溶湯に３０分浸漬させた後に、直ちにアルゴンガスにて急冷した。この複合体を硝酸２０％水溶液中に１８０分浸漬させた。 (Comparative Example 1-1)
Silicon powder and magnesium powder were blended at a ratio of Si: Mg = 55: 45 (atomic%) and dissolved at 1087 ° C. in an argon atmosphere. Thereafter, a silicon alloy tape having a thickness of 1 mm was produced at a cooling rate of 200 K / s using a twin roll casting machine. This was immersed in molten bismuth at 500 ° C. for 30 minutes, and then immediately cooled with argon gas. This composite was immersed in a 20% nitric acid aqueous solution for 180 minutes.
　（比較例１－２）
　平均粒径５μｍのシリコン粒子（ＳＩＥ２３ＰＢ、高純度化学研究所製）を、２０質量％のフッ化水素水と、２５質量％の硝酸を混合した混酸を用いてエッチング処理を行い、ろ過して多孔質シリコン粒子を得た。 (Comparative Example 1-2)
Silicon particles having an average particle size of 5 μm (SIE23PB, manufactured by High Purity Chemical Laboratory) are etched using a mixed acid in which 20% by mass of hydrogen fluoride water and 25% by mass of nitric acid are mixed, filtered, and porous Quality silicon particles were obtained.
　（比較例１－３）
　平均粒径５μｍのシリコン粒子（ＳＩＥ２３ＰＢ、高純度化学研究所製）を用いた。 (Comparative Example 1-3)
Silicon particles having an average particle diameter of 5 μm (SIE23PB, manufactured by High Purity Chemical Laboratory) were used.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　［評価］
　（粒子形状の観察）
　多孔質シリコン粒子の粒子形状の観察を、走査透過型電子顕微鏡（日本電子製、ＪＥＭ　３１００ＦＥＦ）を用いて行った。図１１に、実施例１－１２に係る粒子のＳＥＭ写真を示し、図１２に、比較例１－１に係る粒子のＳＥＭ写真を示す。図１１には、粒径２０ｎｍ～１００ｎｍのシリコン微粒子が互いに接合して多数集まり、多孔質シリコン粒子を形成していることが観察される。一方、図１２では、厚さ５μｍ程度の壁状の構造が観察される。 [Evaluation]
(Observation of particle shape)
The particle shape of the porous silicon particles was observed using a scanning transmission electron microscope (manufactured by JEOL Ltd., JEM 3100FEF). FIG. 11 shows an SEM photograph of the particles according to Example 1-12, and FIG. 12 shows an SEM photograph of the particles according to Comparative Example 1-1. In FIG. 11, it is observed that a large number of silicon fine particles having a particle diameter of 20 nm to 100 nm are joined together to form porous silicon particles. On the other hand, in FIG. 12, a wall-like structure having a thickness of about 5 μm is observed.
　シリコン微粒子の平均粒径は、電子顕微鏡（ＳＥＭ）の画像情報により測定した。また、多孔質シリコン粒子を、半径方向で５０％以上の表面近傍領域と、半径方向で５０％以内の粒子内部領域に分け、それぞれの平均粒径ＤｓとＤｉの比を計算した。Ｄｓ／Ｄｉの値は、実施例においては、いずれも０．５～１．５の間であったが、エッチング法により得た比較例１－２においては、粒子内部領域に比べて、表面近傍領域の微粒子の平均粒径が小さく、Ｄｓ／Ｄｉの値が小さくなった。 The average particle diameter of the silicon fine particles was measured by image information of an electron microscope (SEM). Further, the porous silicon particles were divided into a region near the surface of 50% or more in the radial direction and a particle internal region within 50% in the radial direction, and the ratio of the respective average particle diameters Ds and Di was calculated. The values of Ds / Di were all in the range of 0.5 to 1.5 in the examples, but in Comparative Example 1-2 obtained by the etching method, near the surface compared to the particle internal region. The average particle size of the fine particles in the region was small, and the value of Ds / Di was small.
　シリコン微粒子と、多孔質シリコン粒子のＳｉ濃度は電子線マイクロアナライザ（ＥＰＭＡ）やエネルギー分散型Ｘ線分析（ＥＤＸ）により測定した。何れも、シリコンを８０原子％以上含む。 The Si concentration of silicon fine particles and porous silicon particles was measured by an electron beam microanalyzer (EPMA) or energy dispersive X-ray analysis (EDX). All contain 80 atomic% or more of silicon.
　多孔質シリコン粒子の平均空隙率は、水銀圧入法（ＪＩＳ　Ｒ　１６５５）により１５ｍＬセルを用いて測定した。 The average porosity of the porous silicon particles was measured by a mercury intrusion method (JIS R 1655) using a 15 mL cell.
　また、多孔質シリコン粒子を、半径方向で５０％以上の表面近傍領域と、半径方向で５０％以内の粒子内部領域に分け、それぞれの平均空隙率であるＸｓとＸｉをＳＥＭの画像情報により測定し、ＸｓとＸｉの比を計算した。実施例においてはＸｓ／Ｘｉの値は、０．５～１．５の間にあるが、エッチング法により得た比較例１－２においては、粒子内部領域に比べて、表面近傍領域の細孔構造が発達しているため、Ｘｓ／Ｘｉが大きくなった。 In addition, the porous silicon particles are divided into a region near the surface of 50% or more in the radial direction and a particle internal region within 50% in the radial direction, and the average porosity Xs and Xi are measured by SEM image information. And the ratio of Xs to Xi was calculated. In the examples, the value of Xs / Xi is between 0.5 and 1.5, but in Comparative Example 1-2 obtained by the etching method, the pores in the region near the surface compared to the region inside the particle Xs / Xi increased due to the development of the structure.
　また、図１３は、実施例１－１２にかかる多孔質シリコン粒子を構成するシリコン微粒子を測定したＸ線回折格子像である。シリコンの結晶由来の回折が観察され、点の回折が得られていることから、シリコン微粒子が単結晶シリコンから構成されていることが分かる。 FIG. 13 is an X-ray diffraction grating image obtained by measuring the silicon fine particles constituting the porous silicon particles according to Example 1-12. Diffraction derived from silicon crystals is observed, and point diffraction is obtained, which indicates that the silicon fine particles are composed of single crystal silicon.
　（粒子を負極に用いた際のサイクル特性の評価）
（ｉ）負極スラリーの調製
　実施例や比較例に係る粒子６５質量部とアセチレンブラック（電気化学工業株式会社製）２０質量部の比率でミキサーに投入した。さらに結着剤としてスチレンブタジエンラバー（ＳＢＲ）５質量％のエマルジョン（日本ゼオン（株）製、ＢＭ４００Ｂ）を固形分換算で５質量部、スラリーの粘度を調整する増粘剤としてカルボキシメチルセルロースナトリウム（ダイセル化学工業（株）製）１質量％溶液を固形分換算で１０質量部の割合で混合してスラリーを作製した。
（ｉｉ）負極の作製
　調製したスラリーを自動塗工装置を用いて、厚さ１０μｍの集電体用電解銅箔（古河電気工業（株）製、ＮＣ－ＷＳ）上に１０μｍの厚みで塗布し、７０℃で乾燥させた後、プレスによる調厚工程を経て、リチウムイオン電池用負極を製造した。
（ｉｉｉ）特性評価
　リチウムイオン電池用負極をφ２０ｍｍに切り抜き、対極と参照極に金属Ｌｉを用い、１ｍｏｌ／ＬのＬｉＰＦ６を含むエチレンカーボネートとジエチルカーボネートの混合溶液からなる電解液を注液し、電気化学試験セルを構成した。なお、電気化学試験セルの組み立ては、露点－６０℃以下のグローブボックス内で行った。充放電特性の評価は、初回の放電容量及び５０サイクルの充電・放電後の放電容量を測定し、放電容量の維持率を算出することによって行った。放電容量は、リチウムの吸蔵・放出に有効な活物質Ｓｉの総重量を基準として算出した。まず、２５℃環境下において、電流値を０．１Ｃの定電流条件で充電を行い、電圧値が０．０２Ｖ（参照極Ｌｉ／Ｌｉ＋の酸化還元電位を０Ｖ基準とする、以下同じ）まで低下した時点で充電を停止した。次いで、電流値０．１Ｃの条件で、参照極に対する電圧が１．５Ｖとなるまで放電を行い、０．１Ｃ初期放電容量を測定した。なお、０．１Ｃとは、１０時間で満充電できる電流値である。次いで、０．１Ｃでの充放電速度で上記充放電を５０サイクル繰り返した。初期放電容量に対する、充放電を５０サイクル繰り返したときの放電容量の割合を百分率で求め、５０サイクル後放電容量維持率とした。 (Evaluation of cycle characteristics when particles are used for negative electrode)
(I) Preparation of Negative Electrode Slurry 65 parts by mass of particles according to Examples and Comparative Examples and 20 parts by mass of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) were charged into a mixer. Furthermore, 5 mass parts of styrene butadiene rubber (SBR) emulsion (manufactured by Zeon Corporation, BM400B) as a binder, 5 parts by mass in terms of solid content, and carboxymethyl cellulose sodium (Daicel) as a thickener to adjust the viscosity of the slurry A slurry was prepared by mixing a 1% by mass solution of Chemical Industry Co., Ltd. at a ratio of 10 parts by mass in terms of solid content.
(Ii) Preparation of negative electrode Using the automatic coating apparatus, the prepared slurry was applied to a 10 μm thick electrolytic copper foil for a current collector (manufactured by Furukawa Electric Co., Ltd., NC-WS) at a thickness of 10 μm. After drying at 70 ° C., a negative electrode for a lithium ion battery was manufactured through a thickness adjustment step using a press.
(Iii) Characteristic evaluation The negative electrode for lithium ion batteries is cut out to φ20 mm, metal Li is used for the counter electrode and the reference electrode, and an electrolytic solution composed of a mixed solution of ethylene carbonate and diethyl carbonate containing 1 mol / L LiPF 6 is injected, An electrochemical test cell was constructed. The electrochemical test cell was assembled in a glove box having a dew point of −60 ° C. or lower. The charge / discharge characteristics were evaluated by measuring the initial discharge capacity and the discharge capacity after 50 cycles of charge / discharge, and calculating the discharge capacity retention rate. The discharge capacity was calculated based on the total weight of the active material Si effective for occlusion / release of lithium. First, in a 25 ° C. environment, the current value is charged under a constant current condition of 0.1 C, and the voltage value is reduced to 0.02 V (the redox potential of the reference electrode Li / Li + is based on 0 V, the same applies hereinafter). At that point, charging was stopped. Next, discharging was performed under a condition of a current value of 0.1 C until the voltage with respect to the reference electrode became 1.5 V, and a 0.1 C initial discharge capacity was measured. In addition, 0.1 C is a current value that can be fully charged in 10 hours. Next, the above charge / discharge cycle was repeated 50 cycles at a charge / discharge rate of 0.1C. The ratio of the discharge capacity when charging / discharging was repeated 50 cycles with respect to the initial discharge capacity was obtained as a percentage, and the discharge capacity retention rate after 50 cycles was determined.
　評価結果を表４にまとめた。なお、実施例１－１３から１－１６は、シリコン粒子が大きいことから、乳鉢で粉砕して小さくした粒子を用いて特性評価を行った。例えば、実施例１－１３の多孔質シリコン粒子の粒子径の１３０⇒３３は、平均粒子径１３０μｍであった多孔質シリコン粒子を粉砕して平均粒子径３３μｍの多孔質シリコン粒子を得たということを意味する。 Evaluation results are summarized in Table 4. In Examples 1-13 to 1-16, since the silicon particles were large, the characteristics were evaluated using particles that were pulverized and reduced in a mortar. For example, the porous silicon particles of Example 1-13 having a particle size of 130⇒33 were obtained by pulverizing porous silicon particles having an average particle size of 130 μm to obtain porous silicon particles having an average particle size of 33 μm. Means.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　表に示すとおり、各実施例は、比較例１－１～１－３よりも、５０サイクル後容量維持率が高く、充放電の繰り返しによる放電容量の低下の割合が小さいので、電池の寿命が長いことが予想される。
　各実施例においては、負極活物質が、三次元網目構造を持つ多孔質シリコン粒子であるため、充放電時のＬｉとＳｉの合金化・脱合金化による膨張・収縮の体積変化が生じても、シリコン粒子の割れや微粉化を生じず、放電容量維持率が高い。 As shown in the table, each example has a higher capacity retention rate after 50 cycles than Comparative Examples 1-1 to 1-3, and the rate of decrease in discharge capacity due to repeated charge and discharge is small, so that the battery life is reduced. Expected to be long.
In each example, since the negative electrode active material is a porous silicon particle having a three-dimensional network structure, even if a volume change of expansion / contraction occurs due to alloying / dealloying of Li and Si during charge / discharge. The silicon particles are not cracked or pulverized, and the discharge capacity retention rate is high.
　更に詳細に比較すると、比較例１－１では、中間合金作製時に初晶として純Ｓｉが晶出し、更に凝固末期に共晶組織（ＳｉとＭｇ２Ｓｉ）が生成した。この初晶Ｓｉは１０μｍ程度と粗大なものであった。これは、ビスマス溶湯へ浸漬させても微細化せず逆に粗大化し、エッチング工程を経てもそのままの形で残存した。そのために、Ｌｉの侵入・放出を繰返す際に、粗大ＳｉをはじめとするＳｉ単体が充放電＝ＬｉとＳｉの合金化・脱合金化による膨張・収縮の体積変化に追従できずに、割れや崩壊を起こし、集電パスや電極機能が失われた割合が多くなり、電池の寿命が短くなったと考えられる。 In more detail, in Comparative Example 1-1, pure Si was crystallized as an initial crystal when the intermediate alloy was produced, and a eutectic structure (Si and Mg 2 Si) was formed at the end of solidification. The primary crystal Si was as coarse as about 10 μm. Even if this was immersed in molten bismuth, it did not become finer, but instead became coarse, and remained in the form as it was even after the etching process. Therefore, when repeating the intrusion / release of Li, the Si simple substance including coarse Si cannot follow the volume change of expansion / contraction due to charge / discharge = alloying / dealloying of Li and Si. It is thought that the percentage of the current collection path and electrode function lost due to collapse and the battery life was shortened.
　比較例１－２では、フッ酸や硝酸によるエッチングにより細孔構造を形成したため、粒子中心部に細孔が形成されない箇所が形成された。この芯の部分が、充放電による体積変化に追従できず、サイクル特性が悪いと考えられる。 In Comparative Example 1-2, since the pore structure was formed by etching with hydrofluoric acid or nitric acid, a portion where no pore was formed was formed at the center of the particle. This core portion cannot follow the volume change due to charging / discharging and is considered to have poor cycle characteristics.
　比較例１－３では、細孔構造を持たない単なるシリコン粒子であるため、充放電による体積変化に追従できず、サイクル特性が悪いと考えられる。 In Comparative Example 1-3, since it is a mere silicon particle having no pore structure, it cannot follow the volume change due to charge / discharge, and the cycle characteristics are considered to be poor.
　以下、複合体元素を含む多孔質シリコン複合体粒子に関する実施例２について説明する。
　［実施例２］
　（実施例２－１）
　Ｓｉ：Ｆｅ：Ｍｇ＝２５：５：７０（原子％）の割合でシリコン粉末（塊状　純度９５．０％以上）と鉄粉末（粒状：２ｍｍ、純度：９９．９９９％以上）とマグネシウム粉末（粉末　純度：９８．０％以上）を配合し、これをアルゴン雰囲気中にて１１２０℃で溶解した。その後、単ロール鋳造機を用いて冷却速度：８００Ｋ／ｓで急冷し板厚４０μｍのシリコン合金製リボンを作製した。これを５００℃のビスマス溶湯に１分浸漬させた後に、直ちにアルゴンガスにて急冷した。この処理により、シリコン微粒子と、Ｓｉ－Ｆｅ合金からなるシリコン化合物粒子と、Ｍｇ－Ｂｉ合金またはＢｉからなる第２相の複合体が得られた。この複合体を硝酸２０％水溶液中に５分浸漬させ、多孔質シリコン複合体粒子を得た。 Hereinafter, Example 2 regarding the porous silicon composite particles containing the composite element will be described.
[Example 2]
Example 2-1
Silicon powder (granular purity: 95.0% or more), iron powder (granular: 2 mm, purity: 99.999% or more) and magnesium powder (powder) at a ratio of Si: Fe: Mg = 25: 5: 70 (atomic%) (Purity: 98.0% or more) was added and dissolved at 1120 ° C. in an argon atmosphere. Thereafter, the ribbon was rapidly cooled using a single roll casting machine at a cooling rate of 800 K / s to produce a silicon alloy ribbon having a thickness of 40 μm. This was immersed in a molten bismuth at 500 ° C. for 1 minute, and immediately quenched with argon gas. By this treatment, silicon fine particles, silicon compound particles made of Si—Fe alloy, and a second phase composite made of Mg—Bi alloy or Bi were obtained. This composite was immersed in a 20% nitric acid aqueous solution for 5 minutes to obtain porous silicon composite particles.
　（実施例２－２～２－８、２－１０、２－１１）
　各実施例、比較例の製造条件を、表５にまとめた。実施例２－２～２－８、２－１０、２－１１は、表５に示す中間合金元素、複合体元素、各元素の配合比率、などの製造条件にて、他は実施例２－１の方法と同様にして多孔質シリコン複合体を得た。なお、実施例２－４においては、連続したリボン状のシリコン合金を形成できず、１～２ｃｍで切れてしまったため、箔片状のシリコン合金となった。実施例２－５の線状シリコン中間合金でのφ１００μｍとは、線状の中間合金の直径が１００μｍであることを意味する。実施例２－８でも同様である。 (Examples 2-2 to 2-8, 2-10, 2-11)
The production conditions for each example and comparative example are summarized in Table 5. Examples 2-2 to 2-8, 2-10, and 2-11 are the same as in Example 2 except for the production conditions such as intermediate alloy elements, composite elements, and blending ratios of each element shown in Table 5. In the same manner as in method 1, a porous silicon composite was obtained. In Example 2-4, a continuous ribbon-like silicon alloy could not be formed and was cut at 1 to 2 cm, resulting in a foil piece-like silicon alloy. In the linear silicon intermediate alloy of Example 2-5, φ100 μm means that the diameter of the linear intermediate alloy is 100 μm. The same applies to Example 2-8.
　（実施例２－９）
　Ｓｉ：Ｖ：Ｐ＝４０：１：５９（原子％）の割合でシリコン粉末とバナジウム粉末とリン粉末を配合し、これをアルゴン雰囲気中にて１４３９℃で溶解した。その後、ガスアトマイズ装置を用いて冷却速度：８００Ｋ／ｓで急冷し平均粒径４０μｍの粒状のシリコン合金を作製した。これを７５０℃のカドミウム溶湯に１分浸漬させた後に、直ちにアルゴンガスにて急冷した。この処理により、シリコン微粒子と、ＳｉとＶの合金からなるシリコン化合物粒子と、Ｐ－Ｃｄ合金またはＣｄからなる第２相の複合体が得られた。この複合体を硝酸２０％水溶液中に５分浸漬させ、多孔質シリコン複合体粒子を得た。また、粒状中間合金でのφ４０μｍとは、粒状中間合金の平均粒径が４０μｍであることを意味する。 (Example 2-9)
Silicon powder, vanadium powder, and phosphorus powder were blended at a ratio of Si: V: P = 40: 1: 59 (atomic%) and dissolved at 1439 ° C. in an argon atmosphere. After that, using a gas atomizer, a rapid cooling was performed at a cooling rate of 800 K / s to produce a granular silicon alloy having an average particle size of 40 μm. This was immersed in molten cadmium at 750 ° C. for 1 minute, and immediately quenched with argon gas. By this treatment, silicon fine particles, silicon compound particles made of an alloy of Si and V, and a second phase composite made of a P—Cd alloy or Cd were obtained. This composite was immersed in a 20% nitric acid aqueous solution for 5 minutes to obtain porous silicon composite particles. Moreover, φ40 μm in the granular intermediate alloy means that the average particle diameter of the granular intermediate alloy is 40 μm.
　（実施例２－１２）
　Ｓｉ：Ｍｇ＝３１：６９（原子％）の割合でシリコンとマグネシウムを配合し、これをアルゴン雰囲気中にて溶解した。その後、鋳型内で冷却し、５ｍｍ角の大きさのシリコン合金製インゴットを作製した。これを１原子％のヒ素を含むビスマス溶湯に１分浸漬させた後に、直ちにアルゴンガスにて急冷した。この処理により、シリコン微粒子と、Ｓｉ－Ａｓ合金からなるシリコン化合物粒子と、Ｍｇ－Ｂｉ合金またはＢｉからなる第２相の複合体が得られた。この複合体を硝酸２０％水溶液中に５０分浸漬させ、多孔質シリコン複合体粒子を得た。 (Example 2-12)
Silicon and magnesium were blended at a ratio of Si: Mg = 31: 69 (atomic%) and dissolved in an argon atmosphere. Then, it cooled in the casting_mold | template and produced the ingot made from a silicon alloy of a magnitude | size of 5 square mm. This was immersed in molten bismuth containing 1 atomic% of arsenic for 1 minute, and then immediately cooled with argon gas. By this treatment, silicon fine particles, silicon compound particles made of Si—As alloy, and a second phase composite made of Mg—Bi alloy or Bi were obtained. This composite was immersed in a 20% nitric acid aqueous solution for 50 minutes to obtain porous silicon composite particles.
　（実施例２－１３～２－１６）
　実施例２－１３～２－１６は、表５に示す中間合金元素、各元素の配合比率、などの製造条件にて、他は実施例２－１２の方法と同様にして多孔質シリコン複合体粒子を得た。なお、実施例２－１３，２－１５，２－１６は、水冷式ブロックを用いて冷却速度を高めている。 (Examples 2-13 to 2-16)
In Examples 2-13 to 2-16, porous silicon composites were produced in the same manner as in Example 2-12 except that the production conditions such as intermediate alloy elements shown in Table 5 and the blending ratio of each element were used. Particles were obtained. In Examples 2-13, 2-15, and 2-16, the water cooling block was used to increase the cooling rate.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　（比較例２－１）
　Ｓｉ：Ｆｅ：Ｍｇ＝５５：１：４４（原子％）の割合でシリコン粉末と鉄粉末とマグネシウム粉末を配合し、これを真空炉中にて１１９５℃で溶解した。その後、銅ブロックを用いて鋳造し、冷却速度：１Ｋ／ｓで５ｍｍ角のシリコン合金製ブロックを作製した。これを５００℃のビスマス溶湯に１０分浸漬させた後に、直ちにアルゴンガスにて急冷した。この２相複合体を硝酸２０％水溶液中に５０分浸漬させた。本比較例は、式（２）のａ÷（ａ＋Ｙ）×１００≦［Ｓｉ最大含有量］を満足しない。
　（比較例２－２）
　Ｓｉ：Ｆｅ：Ｍｇ＝２５：１１：６４（原子％）の割合でシリコン粉末と鉄粉末とマグネシウム粉末を配合し、これを真空炉中にて１１０５℃で溶解した。その後、銅ブロックを用いて鋳造し、冷却速度：１Ｋ／ｓで５ｍｍ角のシリコン合金製ブロックを作製した。これを５００℃のビスマス溶湯に１０分浸漬させた後に、直ちにアルゴンガスにて急冷した。この２相複合体を硝酸２０％水溶液中に５０分浸漬させた。本比較例は、式（２）の１０≦ａ÷（ａ＋Ｙ）×１００を満足しない。
　（比較例２－３）
　Ｓｉ：Ｍｇ＝２４：７６（原子％）の割合でシリコン粉末とマグネシウム粉末を配合し、これを真空炉中にて１０９５℃で溶解した。その後、水冷銅ブロックを用いて鋳造し、冷却速度：４１Ｋ／ｓで５ｍｍ角のシリコン合金製ブロックを作製した。これを５００℃のビスマス８５原子％とニッケル１５原子％の合金浴に１０分浸漬させた後に、直ちにアルゴンガスにて急冷した。この２相複合体を硝酸２０％水溶液中に５０分浸漬させた。本比較例は、合金浴中の単独の複合体元素の濃度が１０原子％を超えている。 (Comparative Example 2-1)
Silicon powder, iron powder, and magnesium powder were blended at a ratio of Si: Fe: Mg = 55: 1: 44 (atomic%), and dissolved at 1195 ° C. in a vacuum furnace. Then, it cast using the copper block, and produced the 5 mm square silicon alloy block at the cooling rate: 1 K / s. This was immersed in a molten bismuth at 500 ° C. for 10 minutes, and then immediately cooled with argon gas. This two-phase composite was immersed in a 20% nitric acid aqueous solution for 50 minutes. This comparative example does not satisfy a ÷ (a + Y) × 100 ≦ [maximum Si content] in formula (2).
(Comparative Example 2-2)
Silicon powder, iron powder, and magnesium powder were blended at a ratio of Si: Fe: Mg = 25: 11: 64 (atomic%), and dissolved at 1105 ° C. in a vacuum furnace. Then, it cast using the copper block, and produced the 5 mm square silicon alloy block at the cooling rate: 1 K / s. This was immersed in a molten bismuth at 500 ° C. for 10 minutes, and then immediately cooled with argon gas. This two-phase composite was immersed in a 20% nitric acid aqueous solution for 50 minutes. This comparative example does not satisfy 10 ≦ a ÷ (a + Y) × 100 of Expression (2).
(Comparative Example 2-3)
Silicon powder and magnesium powder were blended at a ratio of Si: Mg = 24: 76 (atomic%), and dissolved at 1095 ° C. in a vacuum furnace. Thereafter, casting was performed using a water-cooled copper block, and a 5 mm square silicon alloy block was produced at a cooling rate of 41 K / s. This was immersed in an alloy bath of 85 atomic% of bismuth and 15 atomic% of nickel at 500 ° C. for 10 minutes, and then immediately cooled with argon gas. This two-phase composite was immersed in a 20% nitric acid aqueous solution for 50 minutes. In this comparative example, the concentration of the single complex element in the alloy bath exceeds 10 atomic%.
　（比較例２－４）
　Ｓｉ：Ｆｅ＝９０：１０（原子％）の割合でシリコン粉末と鉄粉末を配合し、これを真空炉中にて１３９０℃で溶解した。その後、単ロール鋳造機を用いて冷却速度：１１０Ｋ／ｓで急冷しシリコン合金製箔片を作製した。これをフッ硝酸に１０分浸漬させた後に、水洗した。
　（比較例２－５）
　Ｓｉ：Ｆｅ＝６６：３４（原子％）の割合でシリコン粉末と鉄粉末を配合し、これを真空炉中にて１２５０℃で溶解した。その後、ガスアトマイズ装置で急冷凝固を行い、ＦｅＳｉ２金属間化合物を作製した。これを篩に掛けて粒径分布１～１０μｍの粒子を回収した。この粒子と平均粒径５μｍのシリコン粒子（ＳＩＥ２３ＰＢ、高純度化学研究所製）を２：１で混合し、結着剤としてスチレンブタジエンラバー（ＳＢＲ）を用いて造粒した。 (Comparative Example 2-4)
Silicon powder and iron powder were blended at a ratio of Si: Fe = 90: 10 (atomic%), and dissolved at 1390 ° C. in a vacuum furnace. Then, it cooled rapidly with the cooling rate: 110 K / s using the single roll casting machine, and produced the foil piece made from a silicon alloy. This was immersed in hydrofluoric acid for 10 minutes and then washed with water.
(Comparative Example 2-5)
Silicon powder and iron powder were blended at a ratio of Si: Fe = 66: 34 (atomic%), and dissolved at 1250 ° C. in a vacuum furnace. Thereafter, rapid solidification was performed with a gas atomizer to produce an FeSi 2 intermetallic compound. This was sieved to recover particles having a particle size distribution of 1 to 10 μm. These particles and silicon particles having an average particle size of 5 μm (SIE23PB, manufactured by High Purity Chemical Laboratory) were mixed at a ratio of 2: 1 and granulated using styrene butadiene rubber (SBR) as a binder.
　［評価］
　多孔質シリコン複合体粒子の粒子形状の観察を、走査透過型電子顕微鏡（日本電子製、ＪＥＭ　３１００ＦＥＦ）を用いて行った。図１４に、実施例２－１に係る粒子の表面のＳＥＭ写真を示し、図１５に、実施例２－１に係る粒子内部の断面のＳＥＭ写真を示し、図１６に、実施例２－１に係る粒子の表面のＳＥＭ写真を示す。図１４、図１５には、粒径２０ｎｍ～５０ｎｍのシリコン微粒子が互いに接合して多数集まり、多孔質シリコン複合体粒子を形成していることが観察される。また、図１４と図１５で、空隙率やシリコン微粒子の粒径に大きな差がないことが観察される。図１６には、大きなシリサイドの粒子に、小さなシリコン粒子が接合している様子が観察される。 [Evaluation]
The particle shape of the porous silicon composite particles was observed using a scanning transmission electron microscope (manufactured by JEOL Ltd., JEM 3100FEF). FIG. 14 shows an SEM photograph of the surface of the particle according to Example 2-1, FIG. 15 shows an SEM photograph of a cross section inside the particle according to Example 2-1, and FIG. The SEM photograph of the surface of the particle which concerns on is shown. In FIG. 14 and FIG. 15, it is observed that a large number of silicon fine particles having a particle diameter of 20 nm to 50 nm are joined together to form porous silicon composite particles. Moreover, it is observed in FIG. 14 and FIG. 15 that there is no big difference in the porosity and the particle diameter of silicon fine particles. In FIG. 16, it is observed that small silicon particles are bonded to large silicide particles.
　図１７は、シリコン複合体粒子を構成するシリコン微粒子のＸ線回折格子像である。シリコンの結晶由来のスポットが観察され、シリコン微粒子が単結晶である事がわかる。 FIG. 17 is an X-ray diffraction grating image of silicon fine particles constituting the silicon composite particles. A spot derived from a crystal of silicon is observed, and it can be seen that the silicon fine particle is a single crystal.
　図１８は、シリコン複合体粒子を構成するシリコン微粒子のＴＥＭ写真であり、左上はＴＥＭでの観察領域での制限視野電子線回折像である。ＴＥＭ写真において、一つのシリコン微粒子内に粒界がなく、単結晶であることが分かる。また、制限視野電子線回折像において、シリコンの結晶由来のスポットが観察され、やはりシリコン微粒子が単結晶である事がわかる。 FIG. 18 is a TEM photograph of the silicon fine particles constituting the silicon composite particles, and the upper left is a limited-field electron diffraction image in the observation region of the TEM. In the TEM photograph, it can be seen that there is no grain boundary in one silicon fine particle and it is a single crystal. Further, in the limited-field electron diffraction image, a spot derived from a silicon crystal is observed, and it can be seen that the silicon fine particle is also a single crystal.
　シリコン微粒子とシリコン化合物粒子の平均粒径は、電子顕微鏡（ＳＥＭ）の画像情報により測定した。多孔質シリコン複合体粒子を、半径方向で５０％以上の表面近傍領域と、半径方向で５０％以内の粒子内部領域に分け、それぞれのＳＥＭ写真から、それぞれの平均粒径ＤｓとＤｉを求め、これらの比を計算した。Ｄｓ／Ｄｉの値は、実施例においては、いずれも０．５～１．５の間であったが、エッチング法により得た比較例２－４においては、粒子内部領域に比べて、表面近傍領域の微粒子の平均粒径が小さく、Ｄｓ／Ｄｉの値が小さくなった。多孔質シリコン複合体粒子の平均粒径は、前述の、ＳＥＭの観察とＤＬＳを併用する方法を用いた。 The average particle size of the silicon fine particles and the silicon compound particles was measured by image information of an electron microscope (SEM). The porous silicon composite particles are divided into a surface vicinity region of 50% or more in the radial direction and a particle internal region of 50% or less in the radial direction, and the respective average particle diameters Ds and Di are obtained from the respective SEM photographs, These ratios were calculated. The values of Ds / Di were all in the range of 0.5 to 1.5 in the examples, but in Comparative Example 2-4 obtained by the etching method, near the surface compared to the particle inner region. The average particle size of the fine particles in the region was small, and the value of Ds / Di was small. For the average particle diameter of the porous silicon composite particles, the above-described method using SEM observation and DLS was used.
　シリコン微粒子のＳｉ濃度と、多孔質シリコン複合体粒子のＳｉと複合体元素の濃度などはＩＣＰ発光分光分析計により測定した。何れの実施例においても、シリコン微粒子はシリコンを８０原子％以上含む。 The Si concentration of silicon fine particles and the concentration of Si and complex elements in porous silicon composite particles were measured with an ICP emission spectrometer. In any embodiment, the silicon fine particles contain 80 atomic% or more of silicon.
　多孔質シリコン複合体粒子の平均空隙率は、水銀圧入法（ＪＩＳ　Ｒ　１６５５）により１５ｍＬセルを用いて測定した。 The average porosity of the porous silicon composite particles was measured by a mercury intrusion method (JIS R 1655) using a 15 mL cell.
　また、多孔質シリコン複合体粒子を、半径方向で５０％以上の表面近傍領域と、半径方向で５０％以内の粒子内部領域に分け、それぞれの領域内の任意の箇所を表面走査型電子顕微鏡で観察し、それぞれの平均空隙率であるＸｓとＸｉを求め、ＸｓとＸｉの比を計算した。実施例においてはＸｓ／Ｘｉの値は、０．５～１．５の間にあるが、エッチング法により得た比較例２－４においては、粒子内部領域に比べて、表面近傍領域の細孔構造が発達しているため、Ｘｓ／Ｘｉが大きくなった。 Further, the porous silicon composite particles are divided into a surface vicinity region of 50% or more in the radial direction and a particle internal region of 50% or less in the radial direction, and an arbitrary portion in each region is analyzed with a surface scanning electron microscope. Observed, Xs and Xi were obtained as the average porosity, and the ratio of Xs and Xi was calculated. In the examples, the value of Xs / Xi is between 0.5 and 1.5. However, in Comparative Example 2-4 obtained by the etching method, the pores in the region near the surface compared to the region inside the particle Xs / Xi increased due to the development of the structure.
　（粒子を負極に用いた際のサイクル特性の評価）
（ｉ）負極スラリーの調製
シリコン粒子を微粒子化粉砕処理で粗な粒子へ粉砕し、それを造粒することで１～２０μｍのポーラス体を成形した。実施例や比較例に係る粒子６５質量部とアセチレンブラック（電気化学工業株式会社製）２０質量部の比率でミキサーに投入した。さらに結着剤としてスチレンブタジエンラバー（ＳＢＲ）５質量％のエマルジョン（日本ゼオン（株）製、ＢＭ４００Ｂ）を固形分換算で５質量部、スラリーの粘度を調整する増粘剤としてカルボキシメチルセルロースナトリウム（ダイセル化学工業（株）製）１質量％溶液を固形分換算で１０質量部の割合で混合してスラリーを作製した。
（ｉｉ）負極の作製
　調製したスラリーを自動塗工装置を用いて、厚さ１０μｍの集電体用電解銅箔（古河電気工業（株）製、ＮＣ－ＷＳ）上に１０μｍの厚みで塗布し、７０℃で乾燥させた後、プレスによる調厚工程を経て、リチウムイオン電池用負極を製造した。
（ｉｉｉ）特性評価
　リチウムイオン電池用負極をφ２０ｍｍに切り抜き、対極と参照極に金属Ｌｉを用い、１ｍｏｌ／ＬのＬｉＰＦ６を含むエチレンカーボネートとジエチルカーボネートの混合溶液からなる電解液を注液し、電気化学試験セルを構成した。なお、電気化学試験セルの組み立ては、露点－６０℃以下のグローブボックス内で行った。充放電特性の評価は、初回の放電容量及び５０サイクルの充電・放電後の放電容量を測定し、放電容量の維持率を算出することによって行った。放電容量は、シリサイドと、リチウムの吸蔵・放出に有効な活物質Ｓｉの総重量を基準として算出した。まず、２５℃環境下において、電流値を０．１Ｃの定電流条件で充電を行い、電圧値が０．０２Ｖ（参照極Ｌｉ／Ｌｉ＋の酸化還元電位を０Ｖ基準とする、以下同じ）まで低下した時点で充電を停止した。次いで、電流値０．１Ｃの条件で、参照極に対する電圧が１．５Ｖとなるまで放電を行い、０．１Ｃ初期放電容量を測定した。なお、０．１Ｃとは、１０時間で満充電できる電流値である。次いで、０．１Ｃでの充放電速度で上記充放電を５０サイクル繰り返した。初期放電容量に対する、充放電を５０サイクル繰り返したときの放電容量の割合を百分率で求め、５０サイクル後放電容量維持率とした。 (Evaluation of cycle characteristics when particles are used for negative electrode)
(I) Preparation of Negative Electrode Slurry Silicon particles were pulverized into coarse particles by micronization pulverization and granulated to form a 1 to 20 μm porous body. The mixture was charged into a mixer at a ratio of 65 parts by mass of particles according to Examples and Comparative Examples and 20 parts by mass of acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.). Furthermore, 5 mass parts of styrene butadiene rubber (SBR) emulsion (manufactured by Zeon Corporation, BM400B) as a binder, 5 parts by mass in terms of solid content, and carboxymethyl cellulose sodium (Daicel) as a thickener to adjust the viscosity of the slurry A slurry was prepared by mixing a 1% by mass solution of Chemical Industry Co., Ltd. at a ratio of 10 parts by mass in terms of solid content.
(Ii) Preparation of negative electrode Using the automatic coating apparatus, the prepared slurry was applied to a 10 μm thick electrolytic copper foil for a current collector (manufactured by Furukawa Electric Co., Ltd., NC-WS) at a thickness of 10 μm. After drying at 70 ° C., a negative electrode for a lithium ion battery was manufactured through a thickness adjustment step using a press.
(Iii) Characteristic evaluation The negative electrode for lithium ion batteries is cut out to φ20 mm, metal Li is used for the counter electrode and the reference electrode, and an electrolytic solution composed of a mixed solution of ethylene carbonate and diethyl carbonate containing 1 mol / L LiPF 6 is injected, An electrochemical test cell was constructed. The electrochemical test cell was assembled in a glove box having a dew point of −60 ° C. or lower. The charge / discharge characteristics were evaluated by measuring the initial discharge capacity and the discharge capacity after 50 cycles of charge / discharge, and calculating the discharge capacity retention rate. The discharge capacity was calculated based on the total weight of silicide and active material Si effective for occlusion / release of lithium. First, in a 25 ° C. environment, the current value is charged under a constant current condition of 0.1 C, and the voltage value is reduced to 0.02 V (the redox potential of the reference electrode Li / Li + is based on 0 V, the same applies hereinafter). At that point, charging was stopped. Next, discharging was performed under a condition of a current value of 0.1 C until the voltage with respect to the reference electrode became 1.5 V, and a 0.1 C initial discharge capacity was measured. In addition, 0.1 C is a current value that can be fully charged in 10 hours. Next, the above charge / discharge cycle was repeated 50 cycles at a charge / discharge rate of 0.1C. The ratio of the discharge capacity when charging / discharging was repeated 50 cycles with respect to the initial discharge capacity was obtained as a percentage, and the discharge capacity retention rate after 50 cycles was determined.
　評価結果を表６にまとめた。なお、実施例２－１３から２－１６、比較例２－３は、シリコン粒子が大きいことから、乳鉢で粉砕して小さくした粒子を用いて特性評価を行った。例えば、実施例２－１３の多孔質シリコン複合体粒子の平均粒径の１３０⇒３３は、平均粒径１３０μｍであった多孔質シリコン複合体粒子を粉砕して平均粒径３３μｍの多孔質シリコン複合体粒子を得たということを意味する。 Evaluation results are summarized in Table 6. In Examples 2-13 to 2-16 and Comparative Example 2-3, since the silicon particles were large, the characteristics were evaluated using particles that were pulverized and reduced in a mortar. For example, the average particle size 130⇒33 of the porous silicon composite particles of Example 2-13 is obtained by pulverizing the porous silicon composite particles having an average particle size of 130 μm to obtain the porous silicon composite particles having an average particle size of 33 μm. It means that body particles were obtained.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　表に示すとおり、各実施例は、各比較例よりも、５０サイクル後容量維持率が高く、充放電の繰り返しによる放電容量の低下の割合が小さいので、電池の寿命が長いことが予想される。
　各実施例においては、負極活物質が、三次元網目構造を持つ多孔質シリコン複合体粒子であるため、充放電時のＬｉとＳｉの合金化・脱合金化による膨張・収縮の体積変化が生じても、シリコン複合体粒子の割れや微粉化を生じず、放電容量維持率が高い。 As shown in the table, each example has a higher capacity retention rate after 50 cycles than each comparative example, and the rate of decrease in discharge capacity due to repeated charge and discharge is small, so the battery life is expected to be long. .
In each example, since the negative electrode active material is a porous silicon composite particle having a three-dimensional network structure, volume change of expansion / contraction occurs due to alloying / dealloying of Li and Si during charge / discharge. However, the silicon composite particles are not cracked or pulverized, and the discharge capacity retention rate is high.
　更に詳細に比較すると比較例２－１では、中間合金作製時に初晶として純Ｓｉが晶出し、更に凝固末期に共晶組織（ＳｉとＭｇ２Ｓｉ）が生成した。この初晶Ｓｉは１０μｍ程度と粗大なものであった。これは、ビスマス溶湯へ浸漬させても微細化せず、エッチング工程を経てもそのままの形で残存した。その為に、Ｌｉの侵入・放出を繰返す際に、粗大ＳｉをはじめとするＳｉ単体が充放電＝ＬｉとＳｉの合金化・脱合金化による膨張・収縮の体積変化に追従できずに、割れや崩壊を起こり、集電パスや電極機能が失われた割合が多くなり、電池の寿命が短くなったと考えられる。 In more detail, in Comparative Example 2-1, pure Si was crystallized as an initial crystal when the intermediate alloy was produced, and a eutectic structure (Si and Mg 2 Si) was formed at the end of solidification. The primary crystal Si was as coarse as about 10 μm. Even if it was immersed in molten bismuth, it did not become finer and remained as it was even after the etching process. For this reason, when repeating the intrusion / release of Li, Si alone, including coarse Si, is unable to follow the volume change of expansion / contraction due to charge / discharge = Li / Si alloying / dealloying, and cracking. It is thought that the rate at which the current collection path and electrode function were lost increased and the battery life was shortened.
　比較例２－２では、シリコンに比べて複合体元素である鉄の量が多く、ほとんどのシリコンがシリサイドを形成してしまったため、放電容量が小さかった。 In Comparative Example 2-2, the amount of iron, which is a complex element, was larger than that of silicon, and since most silicon formed silicide, the discharge capacity was small.
　比較例２－３では、浸漬した溶湯に添加した複合体元素であるＮｉの量が多く、ほとんどのシリコンがシリサイドを形成してしまったため、放電容量が小さかった。 In Comparative Example 2-3, the amount of Ni as a complex element added to the immersed molten metal was large, and most of the silicon formed silicide, so the discharge capacity was small.
　比較例２－４では、フッ酸や硝酸によるエッチングにより細孔構造を形成したため、粒子中心部に細孔が形成されない箇所が形成された。この芯の部分が、充放電による体積変化に追従できず、サイクル特性が悪いと考えられる。 In Comparative Example 2-4, since the pore structure was formed by etching with hydrofluoric acid or nitric acid, a portion where no pore was formed was formed at the center of the particle. This core portion cannot follow the volume change due to charging / discharging and is considered to have poor cycle characteristics.
　比較例２－５では、細孔構造を持たない単なる粒子であるため、充放電による体積変化に追従できず、サイクル特性が悪いと考えられる。 In Comparative Example 2-5, since it is a simple particle having no pore structure, it cannot follow the volume change due to charge / discharge, and the cycle characteristics are considered to be poor.
　以上、添付図面を参照しながら、本発明の好適な実施形態について説明したが、本発明は係る例に限定されない。当業者であれば、本願で開示した技術的思想の範疇内において、各種の変更例または修正例に想到しえることは明らかであり、それらについても当然に本発明の技術的範囲に属するものと了解される。 The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.
　本発明にかかる多孔質シリコン複合体粒子は、リチウムイオン電池の負極に用いられるだけでなく、リチウム・イオン・キャパシタの負極、太陽電池、発光材料、フィルター用素材としても用いられることができる。 The porous silicon composite particles according to the present invention can be used not only for a negative electrode of a lithium ion battery but also as a negative electrode of a lithium ion capacitor, a solar cell, a light emitting material, and a filter material.
　１………多孔質シリコン粒子
　３………シリコン微粒子
　Ｓ………表面近傍領域
　Ｉ………粒子内部領域
　７………シリコン中間合金
　９………第２相
　１１………単ロール鋳造機
　１３………シリコン合金
　１５………るつぼ
　１７………鋼製ロール
　１９………リボン状シリコン中間合金
　２１………溶湯浸漬装置
　２３………溶湯
　２５………シンクロール
　２７………サポートロール
　３１………ガスアトマイズ装置
　３３………るつぼ
　３５………ノズル
　３６………噴出ガス
　３７………ガス噴射機
　３８………ガスジェット流
　３９………粉末状シリコン中間合金
　４１………回転円盤アトマイズ装置
　４３………るつぼ
　４５………ノズル
　４９………回転円盤
　５１………粉末状シリコン合金
　５３………るつぼ
　５５………鋳型
　５７………塊状シリコン中間合金
　６１………溶湯浸漬装置
　６３………粒状シリコン中間合金
　６５………浸漬用籠
　６７………押付けシリンダー
　６９………溶湯
　７１………溶湯浸漬装置
　７３………粒状シリコン中間合金
　７５………浸漬用籠
　７７………押付けシリンダー
　７９………溶湯
　８１………機械式撹拌機
　８３………ガス吹き込みプラグ
　１０１………多孔質シリコン複合体粒子
　１０３………シリコン微粒子
　１０５………シリコン化合物粒子
　Ｓ………表面近傍領域
　Ｉ………粒子内部領域
　１０７………シリコン中間合金
　１０９………第２相
　１１１………シリコン中間合金
  DESCRIPTION OF SYMBOLS 1 ......... Porous silicon particle 3 ......... Silicon fine particle S ......... Surface vicinity region I ......... Particle internal region 7 ......... Silicon intermediate alloy 9 ......... Second phase 11 ......... Single roll casting machine 13 ... …… Silicon alloy 15 ……… Crucible 17 ……… Steel roll 19 ……… Ribbon-like silicon intermediate alloy 21 ……… Melting device 23 ……… Melting metal 25 ……… Sink roll 27 ……… Support Roll 31 ……… Gas atomizing device 33 ………… Crucible 35 ……… Nozzle 36 ……… Gas spray 37 ……… Gas jet 38 ……… Gas jet flow 39 ……… Powdered silicon intermediate alloy 41 ……… Rotating disk atomizer 43 ... …… Crucible 45 ……… Nozzle 49 ……… Rotating disk 51 ……… Powdered silicon alloy 53 ……… Crucible 55 ……… Mold 57 ……… Lumped silicon intermediate 61 .... Molten metal dipping device 63 ....... Granular silicon intermediate alloy 65 ... ... Dipping rod 67 ... ... Pressing cylinder 69 ... ... Molten metal 71 ... ... Molten metal dipping device 73 ... ... Granular silicon intermediate alloy 75 ... …… Immersion bowl 77 ……… Pressing cylinder 79 ……… Melt 81 ……… Mechanical stirrer 83 ……… Gas blowing plug 101 ……… Porous silicon composite particles 103 ……… Silicon fine particles 105 …… ... Silicon compound particles S ......... Near surface area I ...... Particle internal area 107 ......... Silicon intermediate alloy 109 ......... Second phase 111 ......... Silicon intermediate alloy

Claims (34)

  1. 　複数のシリコン微粒子が接合してなる多孔質シリコン粒子であって、
    　前記多孔質シリコン粒子の平均粒径が０．１μｍ～１０００μｍであり、
    　前記多孔質シリコン粒子は連続した空隙を有する三次元網目構造を有し、
    　前記多孔質シリコン粒子の平均空隙率が１５～９３％であり、
    　半径方向で５０％以上の表面近傍領域の空隙率Ｘｓと、半径方向で５０％以内の粒子内部領域の空隙率Ｘｉの比であるＸｓ／Ｘｉが、０．５～１．５であり、
    　酸素を除く元素の比率でシリコンを８０原子％以上含む
    ことを特徴とする多孔質シリコン粒子。     Porous silicon particles formed by bonding a plurality of silicon fine particles,
    The porous silicon particles have an average particle size of 0.1 μm to 1000 μm;
    The porous silicon particles have a three-dimensional network structure having continuous voids,
    The average porosity of the porous silicon particles is 15 to 93%,
    The ratio Xs / Xi, which is the ratio of the porosity Xs of the near-surface region of 50% or more in the radial direction and the porosity Xi of the particle internal region within 50% in the radial direction, is 0.5 to 1.5,
    A porous silicon particle comprising 80 atomic% or more of silicon in a ratio of elements excluding oxygen.
  2. 　前記シリコン微粒子が、平均粒径または平均支柱径が２ｎｍ～２μｍであり、
    　半径方向で５０％以上の表面近傍領域の前記シリコン微粒子の平均粒径Ｄｓと、半径方向で５０％以内の粒子内部領域の前記シリコン微粒子の平均粒径Ｄｉの比であるＤｓ／Ｄｉが、０．５～１．５であり、
    　前記シリコン微粒子が、酸素を除く元素の比率でシリコンを８０原子％以上含むことを特徴とする中実なシリコン微粒子であることを特徴とする請求項１に記載の多孔質シリコン粒子。     The silicon fine particles have an average particle diameter or average column diameter of 2 nm to 2 μm,
    The ratio Ds / Di, which is the ratio of the average particle diameter Ds of the silicon fine particles in the region near the surface of 50% or more in the radial direction and the average particle diameter Di of the silicon fine particles in the particle inner region within 50% in the radial direction, .5 to 1.5,
    2. The porous silicon particle according to claim 1, wherein the silicon fine particle is a solid silicon fine particle containing 80 atomic% or more of silicon in an element ratio excluding oxygen.
  3. 　前記シリコン微粒子間の接合部の面積が、前記シリコン微粒子の表面積の３０％以下であることを特徴とする請求項１に記載の多孔質シリコン粒子。 2. The porous silicon particle according to claim 1, wherein the area of the joint between the silicon fine particles is 30% or less of the surface area of the silicon fine particles.
  4. 　複数のシリコン微粒子と複数のシリコン化合物粒子が接合してなる多孔質シリコン複合体粒子であって、
    　前記シリコン化合物粒子は、シリコンと、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｏ、Ｃｒ、Ｃｕ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｌｕ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素との化合物を含み、
    　前記多孔質シリコン複合体粒子の平均粒径が、０．１μｍ～１０００μｍであり、
    　多孔質シリコン複合体粒子が、連続した空隙からなる三次元網目構造を有する
    ことを特徴とする多孔質シリコン複合体粒子。     A porous silicon composite particle formed by bonding a plurality of silicon fine particles and a plurality of silicon compound particles,
    The silicon compound particles include silicon, As, Ba, Ca, Ce, Co, Cr, Cu, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, and Pt. One or more complex elements selected from the group consisting of, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr And a compound with
    The porous silicon composite particles have an average particle size of 0.1 μm to 1000 μm,
    A porous silicon composite particle, wherein the porous silicon composite particle has a three-dimensional network structure composed of continuous voids.
  5. 　前記シリコン微粒子の平均粒径または平均支柱径が、２ｎｍ～２μｍであり、
    　前記シリコン微粒子が、酸素を除く元素の比率でシリコンを８０原子％以上含む中実なシリコン微粒子である
    　ことを特徴とする請求項４に記載の多孔質シリコン複合体粒子。     The average particle diameter or average column diameter of the silicon fine particles is 2 nm to 2 μm;
    The porous silicon composite particle according to claim 4, wherein the silicon fine particle is a solid silicon fine particle containing 80 atomic% or more of silicon in a ratio of an element excluding oxygen.
  6. 　前記シリコン化合物粒子の平均粒径が５０ｎｍ～５０μｍであり、
    　前記シリコン化合物粒子が、酸素を除く元素の比率で、５０～９０原子％のシリコンを含むことを特徴とする中実なシリコン化合物の粒子である
    　ことを特徴とする請求項４に記載の多孔質シリコン複合体粒子。     The silicon compound particles have an average particle size of 50 nm to 50 μm;
    The porous material according to claim 4, wherein the silicon compound particles are solid silicon compound particles containing 50 to 90 atomic% of silicon in a ratio of elements excluding oxygen. Silicon composite particles.
  7. 　前記多孔質シリコン複合体粒子の半径方向で５０％以上の表面近傍領域の前記シリコン微粒子の平均粒径Ｄｓと、前記多孔質シリコン複合体粒子の半径方向で５０％以内の粒子内部領域の前記シリコン微粒子の平均粒径Ｄｉの比であるＤｓ／Ｄｉが、０．５～１．５であることを特徴とする請求項４に記載の多孔質シリコン複合体粒子。 The average particle diameter Ds of the silicon fine particles in the surface vicinity region of 50% or more in the radial direction of the porous silicon composite particles, and the silicon in the particle inner region within 50% in the radial direction of the porous silicon composite particles The porous silicon composite particle according to claim 4, wherein Ds / Di, which is a ratio of the average particle diameter Di of the fine particles, is 0.5 to 1.5.
  8. 　前記多孔質シリコン複合体粒子の半径方向で５０％以上の表面近傍領域の空隙率Ｘｓと、前記多孔質シリコン複合体粒子の半径方向で５０％以内の粒子内部領域の空隙率Ｘｉの比であるＸｓ／Ｘｉが、０．５～１．５であることを特徴とする請求項４に記載の多孔質シリコン複合体粒子。 The ratio between the porosity Xs of the surface vicinity region of 50% or more in the radial direction of the porous silicon composite particles and the porosity Xi of the particle internal region within 50% in the radial direction of the porous silicon composite particles. The porous silicon composite particle according to claim 4, wherein Xs / Xi is 0.5 to 1.5.
  9. 　シリコンと、一つ以上の下記表１に記載の中間合金元素との合金であり、シリコンの割合が全体の１０原子％以上であり、含有する前記中間合金元素に対応する下記表１中のＳｉ最大含有量の中で最も高い値以下であるシリコン中間合金を作製する工程（ａ）と、
    　前記中間合金元素に対応する下記表１記載の１つ以上の溶湯元素の溶湯に浸漬させることで、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、
    　を具備し、
    　前記第２相が、前記中間合金元素と前記溶湯元素の合金および／または前記中間合金元素と置換した前記溶湯元素で構成される
    　ことを特徴とする多孔質シリコン粒子の製造方法。
    Figure JPOXMLDOC01-appb-T000001
         It is an alloy of silicon and one or more intermediate alloy elements shown in the following Table 1, the ratio of silicon is 10 atomic% or more of the total, and Si in Table 1 below corresponding to the intermediate alloy element contained A step (a) of producing a silicon intermediate alloy having a maximum content of not more than the highest value;
    A step (b) of separating the silicon fine particles and the second phase by immersing them in a melt of one or more melt elements listed in Table 1 corresponding to the intermediate alloy element;
    Removing the second phase (c);
    Comprising
    The method for producing porous silicon particles, wherein the second phase is composed of an alloy of the intermediate alloy element and the molten element and / or the molten element replaced with the intermediate alloy element.
    Figure JPOXMLDOC01-appb-T000001
  10. 　前記工程（ａ）において、
    　前記シリコン中間合金が、厚さ０．１μｍ～２ｍｍのリボン状、箔片状または線状であるか、粒径１０μｍ～５０ｍｍの粒状または塊状であることを特徴とする請求項９に記載の多孔質シリコン粒子の製造方法。     In the step (a),
    The porous silicon alloy according to claim 9, wherein the silicon intermediate alloy has a ribbon shape, a foil piece shape or a linear shape with a thickness of 0.1 µm to 2 mm, or a granular shape or a lump shape with a particle size of 10 µm to 50 mm. For producing fine silicon particles.
  11. 　前記工程（ｃ）が、
    　前記第２相を、酸、アルカリ、有機溶剤の少なくとも１つ以上で溶解して除去する工程、
    　または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする請求項９に記載の多孔質シリコン粒子の製造方法。     The step (c)
    Removing the second phase by dissolving with at least one of an acid, an alkali, and an organic solvent;
    Alternatively, the method for producing porous silicon particles according to claim 9, further comprising a step of evaporating and removing only the second phase by heating and depressurizing.
  12. 　前記工程（ａ）が、
    　前記シリコンと前記中間合金元素の溶湯を、単ロール鋳造機によりリボン状のシリコン中間合金を製造する工程であることを特徴とする請求項９に記載の多孔質シリコン粒子の製造方法。     The step (a)
    10. The method for producing porous silicon particles according to claim 9, wherein the silicon and the intermediate alloy element are melted in a step of producing a ribbon-like silicon intermediate alloy by a single roll casting machine.
  13. 　前記工程（ａ）が、
    　前記シリコンと前記中間合金元素の溶湯を、ガスアトマイズ法又は回転円盤アトマイズ法を用いて粉末状のシリコン中間合金を製造する工程であることを特徴とする請求項９に記載の多孔質シリコン粒子の製造方法。     The step (a)
    10. The production of porous silicon particles according to claim 9, which is a step of producing a powdery silicon intermediate alloy by using a gas atomization method or a rotating disk atomization method for the molten metal of silicon and the intermediate alloy element. Method.
  14. 　前記工程（ａ）が、
    　前記シリコンと前記中間合金元素の溶湯を、鋳型内にて冷却して塊状のシリコン中間合金を製造する工程を含むことを特徴とする請求項９に記載の多孔質シリコン粒子の製造方法。     The step (a)
    The method for producing porous silicon particles according to claim 9, comprising a step of producing a lump silicon intermediate alloy by cooling the molten metal of silicon and the intermediate alloy element in a mold.
  15. 　Ｃｕにシリコンの割合が全体の１０～３０原子％になるようにシリコンを配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を製造する工程（ａ）と、
    　前記シリコン合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、
    　を具備し、
    　前記工程（ｂ）で前記第２相が、前記Ｃｕと前記溶湯元素の合金および／または前記Ｃｕと置換した前記溶湯元素で構成される
    ことを特徴とする多孔質シリコン粒子の製造方法。     Silicon is mixed with Cu so that the silicon ratio is 10 to 30 atomic% of the total, and ribbons, foil pieces and lines with a thickness of 0.1 μm to 2 mm, or particles and blocks with a particle size of 10 μm to 50 mm are used. The step (a) of producing a silicon intermediate alloy of
    The silicon alloy is immersed in a melt mainly composed of one or more melt elements selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, and Zn, and silicon fine particles, a second phase, (B) separating into
    Removing the second phase (c);
    Comprising
    The method for producing porous silicon particles, wherein in the step (b), the second phase is composed of an alloy of the Cu and the molten metal element and / or the molten metal element substituted for the Cu.
  16. 　Ｍｇにシリコンの割合が全体の１０～５０原子％になるようにシリコンを配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を製造する工程（ａ）と、
    　前記シリコン合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、
    　を具備し、
    　前記工程（ｂ）で前記第２相が、前記Ｍｇと前記溶湯元素の合金および／または前記Ｍｇと置換した前記溶湯元素で構成される
    ことを特徴とする多孔質シリコン粒子の製造方法。     Silicon is blended in Mg so that the proportion of silicon is 10 to 50 atomic%, and ribbons, foil pieces and lines with a thickness of 0.1 μm to 2 mm, or particles and blocks with a particle size of 10 μm to 50 mm are used. The step (a) of producing a silicon intermediate alloy of
    The silicon alloy is immersed in a melt mainly composed of one or more molten elements selected from the group consisting of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, Tl, and Zn, A step (b) of separating the silicon fine particles into a second phase;
    Removing the second phase (c);
    Comprising
    The method for producing porous silicon particles according to the step (b), wherein the second phase is composed of an alloy of the Mg and the molten metal element and / or the molten metal element substituted for the Mg.
  17. 　Ｎｉにシリコンの割合が全体の１０～５５原子％になるようにシリコンを配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を製造する工程（ａ）と、
    　前記シリコン合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、
    　を具備し、
    　前記工程（ｂ）で前記第２相が、前記Ｎｉと前記溶湯元素の合金および／または前記Ｎｉと置換した前記溶湯元素で構成される
    ことを特徴とする多孔質シリコン粒子の製造方法。     Silicon is blended into Ni so that the proportion of silicon is 10 to 55 atomic% of the whole, and ribbons, foil pieces, and wires with a thickness of 0.1 μm to 2 mm, or particles and blocks with a particle size of 10 μm to 50 mm are used. (A) producing a silicon intermediate alloy of
    The silicon alloy is immersed in a melt mainly composed of one or more melt elements selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, and Zn, and silicon fine particles, a second phase, (B) separating into
    Removing the second phase (c);
    Comprising
    The method for producing porous silicon particles, wherein in the step (b), the second phase is composed of an alloy of the Ni and the molten element and / or the molten element substituted for the Ni.
  18. 　Ｔｉにシリコンの割合が全体の１０～８２原子％になるようにシリコンを配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を製造する工程（ａ）と、
    　前記シリコン合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、第２相とに分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、
    　を具備し、
    　前記工程（ｂ）で前記第２相が、前記Ｔｉと前記溶湯元素の合金および／または前記Ｔｉと置換した前記溶湯元素で構成される
    ことを特徴とする多孔質シリコン粒子の製造方法。     Silicon is added to Ti so that the ratio of silicon is 10 to 82 atomic% of the whole, and ribbons, foil pieces, and wires with a thickness of 0.1 μm to 2 mm, or particles and blocks with a particle size of 10 μm to 50 mm are used. The step (a) of producing a silicon intermediate alloy of
    The silicon alloy is immersed in a melt mainly composed of one or more molten elements selected from the group consisting of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, Zn, A step (b) of separating the silicon fine particles into a second phase;
    Removing the second phase (c);
    Comprising
    The method for producing porous silicon particles, wherein in the step (b), the second phase is composed of an alloy of the Ti and the molten element and / or the molten element substituted for the Ti.
  19. 　シリコンと、１つ以上の下記表２に記載の中間合金元素と、１つ以上の下記表２に記載の複合体元素との合金であり、前記複合体元素の割合が前記シリコンの１～３３原子％であり、前記シリコンの割合が前記シリコンと前記中間合金元素と前記複合体元素の和に対して１０原子％以上であり、含有する前記中間合金元素に対応する下記表２中のＳｉ最大含有量の値以下であるシリコン中間合金を作製する工程（ａ）と、
    　前記中間合金元素に対応する下記表２記載の１つ以上の溶湯元素の溶湯に浸漬させて、シリコン微粒子と、シリコンと複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記中間合金元素と前記溶湯元素の合金及び／又は前記溶湯元素で構成される
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。
    Figure JPOXMLDOC01-appb-T000002
         An alloy of silicon, one or more intermediate alloy elements described in Table 2 below, and one or more composite elements described in Table 2 below, wherein the ratio of the composite elements is 1 to 33 of the silicon. Si% in Table 2 below corresponding to the intermediate alloy element to be contained, which is 10 atomic% or more with respect to the sum of the silicon, the intermediate alloy element, and the composite element. A step (a) of producing a silicon intermediate alloy having a content value or less;
    A step of immersing in a melt of one or more melt elements shown in Table 2 below corresponding to the intermediate alloy element to separate into silicon fine particles, silicon compound particles of silicon and complex elements, and a second phase ( b) and
    And (c) removing the second phase,
    The method for producing porous silicon composite particles, wherein the second phase is composed of an alloy of the intermediate alloy element and the molten element and / or the molten element.
    Figure JPOXMLDOC01-appb-T000002
  20. 　前記工程（ａ）において、
    　シリコン（Ｘ原子％）と中間合金元素（Ｙ原子％）と１つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）が、以下の式を満足する組成を有するシリコン中間合金を作製することを特徴とする請求項１９に記載の多孔質シリコン複合体粒子の製造方法。
    　　１０≦Ｘ＜[Ｓｉ最大含有量]　　　　　　　　　　　　式（１）
    　　１０≦ａ÷（ａ＋Ｙ）×１００≦[Ｓｉ最大含有量]　　式（２）
    　　　　但し、ａ＝Ｘ－１．５×（Ｚ１+Ｚ２+Ｚ３、・・・・）
    　　　［Ｓｉ最大含有量］は、含有する中間合金元素に対応する表２中のＳｉ最大含有量である。     In the step (a),
    Silicon (X atom%), an intermediate alloy element (Y atom%) and one or more complex elements (Z 1 , Z 2 , Z 3 ,... Atom%) satisfy the following formula: The method for producing porous silicon composite particles according to claim 19, wherein the silicon intermediate alloy is produced.
    10 ≦ X <[maximum Si content] Formula (1)
    10 ≦ a ÷ (a + Y) × 100 ≦ [maximum Si content] Formula (2)
    However, a = X−1.5 × (Z 1 + Z 2 + Z 3 ,...)
    [Si maximum content] is the Si maximum content in Table 2 corresponding to the intermediate alloy element to be contained.
  21. 　シリコンと、表２に記載の一つ以上の中間合金元素との合金であり、シリコンの割合が全体の１０原子％以上であり、含有する前記中間合金元素に対応する表２中のＳｉ最大含有量の中で最も高い値以下であるシリコン中間合金を作成する工程（ａ）と、
    　前記中間合金元素に対応する表２記載の１つ以上の溶湯元素の溶湯であって、前記中間合金元素に対応する表２記載の１つ以上の複合体元素を各１０原子％以下、合計２０原子％以下含む合金浴に浸漬させて、シリコン微粒子と、シリコンと複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、
    　を具備し、
    　前記第２相が、前記中間合金元素と前記溶湯元素の合金及び／又は前記溶湯元素で構成される
    　ことを特徴とする多孔質シリコン複合体粒子の製造方法。     It is an alloy of silicon and one or more intermediate alloy elements shown in Table 2, and the silicon content is 10 atomic% or more of the whole, and the maximum Si content in Table 2 corresponding to the intermediate alloy element contained A step (a) for producing a silicon intermediate alloy which is not more than the highest value among the amounts;
    A melt of one or more molten elements shown in Table 2 corresponding to the intermediate alloy element, wherein one or more complex elements shown in Table 2 corresponding to the intermediate alloy element are each 10 atomic% or less, a total of 20 A step (b) of immersing in an alloy bath containing at most atomic% to separate into silicon fine particles, silicon compound particles of silicon and complex elements, and a second phase;
    Removing the second phase (c);
    Comprising
    The method for producing porous silicon composite particles, wherein the second phase is composed of an alloy of the intermediate alloy element and the molten metal element and / or the molten metal element.
  22. 　前記工程（ａ）において、
    　前記シリコン中間合金が、厚さ０．１μｍ～２ｍｍのリボン状、箔片状または線状であるか、粒径１０μｍ～５０ｍｍの粉末状、粒状または塊状であることを特徴とする請求項１９に記載の多孔質シリコン複合体粒子の製造方法。     In the step (a),
    20. The silicon intermediate alloy according to claim 19, wherein the silicon intermediate alloy has a ribbon shape, a foil piece shape or a linear shape with a thickness of 0.1 μm to 2 mm, or a powder shape, a granular shape or a lump shape with a particle size of 10 μm to 50 mm. A method for producing the described porous silicon composite particles.
  23. 　前記工程（ｃ）が、
    　前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、
    　または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備することを特徴とする請求項１９に記載の多孔質シリコン複合体粒子の製造方法。     The step (c)
    Removing the second phase by dissolving at least one of an acid, an alkali and an organic solvent;
    The method for producing porous silicon composite particles according to claim 19, further comprising a step of evaporating and removing only the second phase by increasing the temperature and reducing the pressure.
  24. 　前記工程（ａ）が、
    　前記シリコンと前記中間合金元素と前記複合体元素の溶湯を、単ロール鋳造機もしくは双ロール鋳造機によりリボン状もしくは薄板状のシリコン中間合金を製造する工程であることを特徴とする請求項１９に記載の多孔質シリコン複合体粒子の製造方法。     The step (a)
    20. The process of producing a ribbon-like or thin-plate-like silicon intermediate alloy from a melt of the silicon, the intermediate alloy element, and the complex element using a single roll casting machine or a twin roll casting machine. A method for producing the described porous silicon composite particles.
  25. 　前記工程（ａ）が、
    　前記シリコンと前記中間合金元素と前記複合体元素の溶湯を、アトマイズ法を用いて粉末状のシリコン中間合金を製造する工程であることを特徴とする請求項１９に記載の多孔質シリコン複合体粒子の製造方法。     The step (a)
    20. The porous silicon composite particle according to claim 19, wherein the silicon, the intermediate alloy element, and the composite element are produced by a process for producing a powdery silicon intermediate alloy using an atomizing method. Manufacturing method.
  26. 　前記工程（ａ）が、
    　前記シリコンと前記中間合金元素と前記複合体元素の溶湯を、鋳型内にて冷却して塊状のシリコン中間合金を製造する工程を含むことを特徴とする請求項１９に記載の多孔質シリコン複合体粒子の製造方法。     The step (a)
    The porous silicon composite according to claim 19, further comprising a step of cooling a molten metal of the silicon, the intermediate alloy element, and the composite element in a mold to produce a bulk silicon intermediate alloy. Particle production method.
  27. 　Ｃｕ（Ｙ原子％）に、シリコンの割合が全体に対して１０～３０原子％（Ｘ原子％）で、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｏ、Ｃｒ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）を請求項２０の式（１）、（２）を満足するように配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粉末状・粒状・塊状のシリコン中間合金を作成する工程（ａ）と、
    　前記シリコン中間合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記Ｃｕと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、
    　前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備する
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。     The percentage of silicon in Cu (Y atom%) is 10 to 30 atom% (X atom%) with respect to the whole, and As, Ba, Ca, Ce, Co, Cr, Er, Fe, Gd, Hf, Mn, From Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr One or more complex elements (Z 1 , Z 2 , Z 3 ,..., Atomic%) selected from the group consisting of the following groups are blended so as to satisfy the formulas (1) and (2) of claim 20. A step (a) of producing a ribbon-like, foil-like, linear, or powder-like, granular, lump-shaped silicon intermediate alloy having a thickness of 0.1 μm to 2 mm, or a particle size of 10 μm to 50 mm;
    The silicon intermediate alloy is immersed in a melt mainly composed of one or more molten elements selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, and Zn, and silicon fine particles, silicon, A step (b) of separating the silicon compound particles of the complex element and the second phase;
    And (c) removing the second phase,
    The second phase is composed of an alloy of the Cu and the molten element and / or the molten element,
    In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is evaporated by heating and decompressing. A method for producing porous silicon composite particles, comprising the step of removing.
  28. 　Ｃｕ（Ｙ原子％）に、シリコンの割合が全体に対して１０～３０原子％（Ｘ原子％）を配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を作成する工程（ａ）と、
    　前記シリコン中間合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯にＡｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｏ、Ｃｒ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作成された合金浴へ浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記Ｃｕと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、
    　前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備する
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。     Combining Cu (Y atom%) with a silicon ratio of 10 to 30 atom% (X atom%) with respect to the whole, ribbon shape, foil piece shape, wire shape, or grain with a thickness of 0.1 μm to 2 mm A step (a) for producing a granular and massive silicon intermediate alloy having a diameter of 10 μm to 50 mm;
    The silicon intermediate alloy is changed to As, Ba, Ca, Ce, Co, Cr, as a main component of one or more molten metal elements selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, and Zn. , Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U , V, W, Y, Yb, Zr are immersed in an alloy bath prepared by adding one or more complex elements selected from the group consisting of V, W, Y, Yb, and Zr to each of 10 atomic% or less, and a total of 20 atomic% or less. And (b) separating silicon, silicon compound particles of the complex element, and a second phase;
    And (c) removing the second phase,
    The second phase is composed of an alloy of the Cu and the molten element and / or the molten element,
    In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is evaporated by heating and decompressing. A method for producing porous silicon composite particles, comprising the step of removing.
  29. 　Ｍｇ（Ｙ原子％）に、シリコンの割合が全体に対して１０～５０原子％（Ｘ原子％）で、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）を請求項２０の式（１）、（２）を満足するように配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粉末状・粒状・塊状のシリコン中間合金を作成する工程（ａ）と、
    　前記シリコン中間合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記Ｍｇと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、
    　前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備する
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。     In Mg (Y atom%), the ratio of silicon is 10 to 50 atom% (X atom%) with respect to the whole, and As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Mn, From Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr 21. One or more complex elements (Z 1 , Z 2 , Z 3 ,... Atomic%) selected from the group consisting of the following groups are blended so as to satisfy the formulas (1) and (2) of claim 20. A step (a) of producing a ribbon-like, foil-like, linear, or powder-like, granular, lump-shaped silicon intermediate alloy having a thickness of 0.1 μm to 2 mm, or a particle size of 10 μm to 50 mm;
    The silicon intermediate alloy is immersed in a melt mainly composed of one or more molten elements selected from the group consisting of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, Tl, and Zn. Separating the silicon fine particles, silicon and silicon compound particles of the complex element, and the second phase (b),
    And (c) removing the second phase,
    The second phase is composed of an alloy of the Mg and the molten element and / or the molten element,
    In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is evaporated by heating and decompressing. A method for producing porous silicon composite particles, comprising the step of removing.
  30. 　Ｍｇ（Ｙ原子％）に、シリコンの割合が全体に対して１０～５０原子％（Ｘ原子％）を配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を作成する工程（ａ）と、
    　前記シリコン中間合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｌ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯にＡｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作成された合金浴へ浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記Ｍｇと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、
    　前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備する
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。     Mg (Y atom%) is mixed with 10 to 50 atom% (X atom%) of silicon relative to the whole, and ribbons, foil pieces, lines, or grains with a thickness of 0.1 μm to 2 mm A step (a) of producing a granular and massive silicon intermediate alloy having a diameter of 10 μm to 50 mm;
    The silicon intermediate alloy is changed to As, Ba, as a main component of one or more molten elements selected from the group consisting of Ag, Al, Au, Be, Bi, Ga, In, Pb, Sb, Sn, Tl, and Zn. , Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te , Th, Ti, Tm, U, V, W, Y, Yb, an alloy formed by adding one or more complex elements selected from the group consisting of 10 atomic% or less, and a total of 20 atomic% or less Dipping in a bath to separate silicon fine particles, silicon and silicon compound particles of the complex element, and the second phase (b);
    And (c) removing the second phase,
    The second phase is composed of an alloy of the Mg and the molten element and / or the molten element,
    In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is evaporated by heating and decompressing. A method for producing porous silicon composite particles, comprising the step of removing.
  31. 　Ｎｉ（Ｙ原子％）に、シリコンの割合が全体に対して１０～５５原子％（Ｙ原子％）で、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）を請求項２０の式（１）、（２）を満足するように配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粉末状・粒状・塊状のシリコン中間合金を作成する工程（ａ）と、
    　前記シリコン中間合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記Ｎｉと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、
    　前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備する
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。     Ni (Y atom%) is 10 to 55 atom% (Y atom%) relative to the whole, and As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V, W, Y, Yb, Zr One or more complex elements (Z 1 , Z 2 , Z 3 ,... Atomic%) selected from the above are blended so as to satisfy the formulas (1) and (2) of claim 20, A step (a) of producing a silicon intermediate alloy in a ribbon shape, foil piece shape, linear shape having a particle size of 0.1 μm to 2 mm, or a powdery shape, granular shape, or a lump shape having a particle size of 10 μm to 50 mm;
    The silicon intermediate alloy is immersed in a melt mainly composed of one or more molten elements selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, and Zn, and silicon fine particles, silicon, A step (b) of separating the silicon compound particles of the complex element and the second phase;
    And (c) removing the second phase,
    The second phase is composed of an alloy of the Ni and the molten element and / or the molten element,
    In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is evaporated by heating and decompressing. A method for producing porous silicon composite particles, comprising the step of removing.
  32. 　Ｎｉ（Ｙ原子％）に、シリコンの割合が全体に対して１０～５５原子％（Ｙ原子％）を配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を作成する工程（ａ）と、
    　前記シリコン中間合金を、Ａｌ、Ｂｅ、Ｃｄ、Ｇａ、Ｉｎ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯にＡｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｉ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作成された合金浴へ浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記Ｎｉと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、
    　前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備する
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。     Ni (Y atom%) is mixed with 10 to 55 atom% (Y atom%) of silicon in the whole, and ribbons, foil pieces, lines, or grains with a thickness of 0.1 μm to 2 mm A step (a) for producing a granular and massive silicon intermediate alloy having a diameter of 10 μm to 50 mm;
    The silicon intermediate alloy is changed to As, Ba, Ca, Ce, Cr, Co, or the like as a main component of one or more molten metal elements selected from the group consisting of Al, Be, Cd, Ga, In, Sb, Sn, and Zn. , Er, Fe, Gd, Hf, Mn, Mo, Nb, Nd, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Ti, Tm, U, V , One or more complex elements selected from the group consisting of W, Y, Yb, and Zr are each immersed in an alloy bath prepared by adding 10 atomic percent or less, and a total of 20 atomic percent or less, silicon fine particles, A step (b) of separating silicon, silicon compound particles of the complex element, and a second phase;
    And (c) removing the second phase,
    The second phase is composed of an alloy of the Ni and the molten element and / or the molten element,
    In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is evaporated by heating and decompressing. A method for producing porous silicon composite particles, comprising the step of removing.
  33. 　Ｔｉ（Ｙ原子％）に、シリコンの割合が全体に対して１０～８０原子％（Ｙ原子％）で、Ａｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｌｕ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素（Ｚ１、Ｚ２、Ｚ３、・・・・原子％）を請求項２０の式（１）、（２）を満足するように配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粉末状・粒状・塊状のシリコン中間合金を作成する工程（ａ）と、
    　前記シリコン中間合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯に浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記Ｔｉと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、
    　前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備する
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。     Ti (Y atomic%) is 10 to 80 atomic% (Y atomic%) of silicon, and As, Ba, Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr, Ta, Te, Th, Tm, U, V, W, Y, Yb, One or more complex elements (Z 1 , Z 2 , Z 3 ,... Atomic%) selected from the group consisting of Zr so as to satisfy the formulas (1) and (2) of claim 20 A step (a) of blending and forming a ribbon-like / foil-like / wire-like silicon intermediate alloy having a thickness of 0.1 μm to 2 mm, or a powdery / granular / lumb-like silicon intermediate alloy having a particle size of 10 μm to 50 mm;
    The silicon intermediate alloy is immersed in a melt mainly composed of one or more molten elements selected from the group consisting of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, and Zn. Separating the silicon fine particles, silicon and silicon compound particles of the complex element, and the second phase (b),
    And (c) removing the second phase,
    The second phase is composed of an alloy of the Ti and the molten element and / or the molten element,
    In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is evaporated by heating and decompressing. A method for producing porous silicon composite particles, comprising the step of removing.
  34. 　Ｔｉ（Ｙ原子％）に、シリコンの割合が全体に対して１０～８０原子％（Ｙ原子％）を配合し、厚さ０．１μｍ～２ｍｍのリボン状・箔片状・線状、または粒径１０μｍ～５０ｍｍの粒状・塊状のシリコン中間合金を作成する工程（ａ）と、
    　前記シリコン中間合金を、Ａｇ、Ａｌ、Ａｕ、Ｂｅ、Ｂｉ、Ｃｄ、Ｇａ、Ｉｎ、Ｐｂ、Ｓｂ、Ｓｎ、Ｚｎからなる群より選ばれる１以上の溶湯元素を主成分とした溶湯にＡｓ、Ｂａ、Ｃａ、Ｃｅ、Ｃｒ、Ｃｏ、Ｅｒ、Ｆｅ、Ｇｄ、Ｈｆ、Ｌｕ、Ｍｇ、Ｍｎ、Ｍｏ、Ｎｂ、Ｎｄ、Ｎｉ、Ｏｓ、Ｐｒ、Ｐｔ、Ｐｕ、Ｒｅ、Ｒｈ、Ｒｕ、Ｓｃ、Ｓｍ、Ｓｒ、Ｔａ、Ｔｅ、Ｔｈ、Ｔｍ、Ｕ、Ｖ、Ｗ、Ｙ、Ｙｂ、Ｚｒからなる群より選ばれた一つ以上の複合体元素を各１０原子％以下、合計２０原子％以下添加し作成された合金浴へ浸漬させて、シリコン微粒子と、シリコンと前記複合体元素のシリコン化合物粒子と、第２相と、に分離させる工程（ｂ）と、
    　前記第２相を取り除く工程（ｃ）と、を具備し、
    　前記第２相が、前記Ｔｉと前記溶湯元素の合金及び／又は前記溶湯元素で構成され、
    　前記工程（ｃ）が、前記第２相を、酸、アルカリ、有機溶剤の少なくても１つ以上で溶解して除去する工程、または、昇温減圧して前記第２相のみを蒸発して除去する工程を具備する
    ことを特徴とする多孔質シリコン複合体粒子の製造方法。     Ti (Y atom%) is mixed with 10 to 80 atom% (Y atom%) of silicon relative to the whole, and ribbons, foil pieces, lines, or grains with a thickness of 0.1 μm to 2 mm A step (a) of producing a granular and massive silicon intermediate alloy having a diameter of 10 μm to 50 mm;
    The silicon intermediate alloy is changed to As, Ba, as a main component of one or more molten elements selected from the group consisting of Ag, Al, Au, Be, Bi, Cd, Ga, In, Pb, Sb, Sn, and Zn. , Ca, Ce, Cr, Co, Er, Fe, Gd, Hf, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, Pr, Pt, Pu, Re, Rh, Ru, Sc, Sm, Sr One or more complex elements selected from the group consisting of Ta, Te, Th, Tm, U, V, W, Y, Yb, and Zr are added at 10 atom% or less for a total of 20 atom% or less. A step (b) of immersing in an alloy bath and separating into silicon fine particles, silicon and silicon compound particles of the complex element, and a second phase;
    And (c) removing the second phase,
    The second phase is composed of an alloy of the Ti and the molten element and / or the molten element,
    In the step (c), the second phase is dissolved and removed with at least one of an acid, an alkali and an organic solvent, or only the second phase is evaporated by heating and decompressing. A method for producing porous silicon composite particles, comprising the step of removing.
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WO2022139243A1 (en) * 2020-12-23 2022-06-30 대주전자재료 주식회사 Porous silicon structure, porous silicon-carbon composite comprising same, and negative electrode active material
WO2022139244A1 (en) * 2020-12-23 2022-06-30 대주전자재료 주식회사 Porous silicon composite, porous silicon-carbon composite comprising same, and anode active material

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