WO2020129975A1 - Active material and all-solid-state battery - Google Patents

Active material and all-solid-state battery Download PDF

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WO2020129975A1
WO2020129975A1 PCT/JP2019/049390 JP2019049390W WO2020129975A1 WO 2020129975 A1 WO2020129975 A1 WO 2020129975A1 JP 2019049390 W JP2019049390 W JP 2019049390W WO 2020129975 A1 WO2020129975 A1 WO 2020129975A1
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active material
axis
positive electrode
negative electrode
layer
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PCT/JP2019/049390
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French (fr)
Japanese (ja)
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岳夫 塚田
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Tdk株式会社
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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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • 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
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • 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 an active material material for a secondary battery and a secondary battery using the same.
  • the present application claims priority based on Japanese Patent Application No. 2018-235091, filed in Japan on December 17, 2018, the contents of which are incorporated herein by reference.
  • polyphosphoric acid-based active materials have been investigated as active materials having excellent crystal stability and thermal stability even at high temperatures.
  • lithium iron phosphate LiFePO 4
  • lithium iron phosphate is a conventional lithium-containing transition metal compound because of its low utilization rate and high rate charge/discharge performance of the active material derived from its low electric conductivity and lithium ion conductivity peculiar to its crystal structure. I/O performance is lower than that of. Therefore, studies have been conducted on lithium vanadium phosphate (Li 3 V 2 (PO 4 ) 3 ) having a reversible potential in the vicinity of about 4 V (vs. Li/Li + ).
  • Lithium vanadium phosphate (Li 3 V 2 (PO 4 ) 3 ) has a plurality of redox potentials (3.8 V, 1.8 V), and therefore Li 3 V 2 (PO 4 ) 3 is used as a positive electrode and a negative electrode.
  • the symmetrical electrode battery used can realize a battery of about 2V class.
  • Patent Document 1 with respect to Li 3 V 2 (PO 4) 3, but is to replace the other metal element V site has been reported, Li 3 V 2 (PO 4 ) 3 than, the other Examples in which the metal element is replaced are not specified.
  • Patent Document 2 reports that by substituting the vanadium site with respect to Li 3 V 2 (PO 4 ) 3 with manganese, high discharge efficiency characteristics can be obtained. Is not mentioned, and there is no description about ionic conductivity.
  • Patent Document 3 by replacing the vanadium site with respect to Li 3 V 2 (PO 4 ) 3 by aluminum, titanium, and zirconium, the high-temperature phase having high ionic conductivity is stabilized at room temperature to thereby obtain a capacitive characteristic.
  • substitution with a rare earth element or an increase in the lattice constant associated with the substitution improves the capacitance characteristics.
  • the present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a battery having a high discharge capacity by increasing the ionic conductivity of an active material. It is in.
  • the present inventors performed element substitution on the V site of Li 3 V 2 (PO 4 ) 3 and widened the crystal lattice, so that lithium ions became easy to move, It was found that the higher the conductivity, the higher the discharge capacity.
  • the following active material and all-solid-state battery are provided.
  • the active material material according to one embodiment of the present invention includes lithium vanadium phosphate that is a polyphosphoric acid compound,
  • the lithium vanadium phosphate satisfies all of the following formulas (1) to (3). 1 ⁇ (A/A0) ⁇ 1.0030 (1) 1 ⁇ (B/B0) ⁇ 1.0051 (2) 1 ⁇ (C/C0) ⁇ 1.043 (3)
  • A represents the length of the a-axis in the crystal axis of the lithium vanadium phosphate
  • A0 represents a in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3.
  • B represents the length of the b axis in the crystal axis of the lithium vanadium phosphate
  • B0 represents the length of the b axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3.
  • C represents the length of the c-axis in the crystal axis of the lithium vanadium phosphate
  • C0 represents the length of the c-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. ..
  • the discharge capacity of the lithium ion secondary battery can be increased. This is because the length of each of the a-axis, the b-axis, and the c-axis of the crystal axes of Li 3 V 2 (PO 4 ) 3 falls within the above range, so that a space where lithium ions easily move is formed in the crystal. It is thought that this is because the lithium ion conductivity was increased and the lithium ion conductivity was increased.
  • part of vanadium is replaced with at least one element selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb. Is preferably provided.
  • an active material material in which the main phase of the lithium vanadium phosphate satisfies the following general formula (I).
  • M represents at least one element selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb, and x satisfies 0 ⁇ x ⁇ 0.3.
  • An all-solid-state battery includes an electrode layer containing the above-mentioned active material and a solid electrolyte layer.
  • an excellent active material material for a lithium-ion secondary battery capable of obtaining a high discharge capacity, particularly an active material material for an all-solid-state battery, and an all-solid-state battery.
  • the schematic cross section of the all-solid-state battery of 1st Embodiment is shown.
  • the schematic cross section of the lithium secondary battery of 2nd Embodiment is shown.
  • the first embodiment relates to an all solid state battery (all solid state secondary battery).
  • the all-solid-state battery 10 has at least one positive electrode layer 1, at least one negative electrode layer 2, and a solid electrolyte 3 sandwiched between the positive electrode layer 1 and the negative electrode layer 2.
  • the positive electrode layer 1, the solid electrolyte 3, and the negative electrode layer 2 are sequentially laminated to form a laminated body 4.
  • the positive electrode layer 1 is connected to a terminal electrode 5 arranged on one end side, and the negative electrode layer 2 is connected to a terminal electrode 6 arranged on the other end side.
  • the positive electrode layer 1 is an example of a first electrode layer
  • the negative electrode layer 2 is an example of a second electrode layer.
  • One of the first electrode layer and the second electrode layer functions as a positive electrode and the other functions as a negative electrode.
  • the positive/negative of the electrode layer changes depending on which polarity is connected to the external terminal.
  • the positive electrode layer 1 and the negative electrode layer 2 are alternately laminated with the solid electrolyte 3 interposed therebetween.
  • the all-solid-state battery 10 is charged and discharged by exchanging lithium ions between the positive electrode layer 1 and the negative electrode layer 2 via the solid electrolyte 3.
  • the positive electrode layer 1 has a positive electrode current collector layer 1A and a positive electrode active material layer 1B containing a positive electrode active material.
  • the negative electrode layer 2 has a negative electrode current collector layer 2A and a negative electrode active material layer 2B containing a negative electrode active material.
  • the positive electrode current collector layer 1A and the negative electrode current collector layer 2A preferably have high conductivity. Therefore, it is preferable to use, for example, silver, palladium, gold, platinum, aluminum, copper, nickel or the like for the positive electrode current collector layer 1A and the negative electrode current collector layer 2A. Among these substances, copper hardly reacts with the positive electrode active material, the negative electrode active material and the solid electrolyte. Therefore, if copper is used for the positive electrode current collector layer 1A and the negative electrode current collector layer 2A, the internal resistance of the all-solid-state battery 10 can be reduced.
  • the materials forming the positive electrode current collector layer 1A and the negative electrode current collector layer 2A may be the same or different.
  • each of the positive electrode current collector layer 1A and the negative electrode current collector layer 2A of the all-solid-state battery 10 in the present embodiment can include an active material material described below. Since the positive electrode current collector layer 1A and the negative electrode current collector layer 2A each contain an active material, the positive electrode current collector layer 1A and the positive electrode active material layer 1B and the negative electrode current collector layer 2A and the negative electrode active material layer 2B are formed. Adhesion can be improved.
  • the positive electrode active material layer 1B is formed on one side or both sides of the positive electrode current collector layer 1A.
  • the positive electrode active material layer 1B in the positive electrode layer 1 located at the uppermost layer may be provided on only one surface on the lower side in the stacking direction.
  • the negative electrode active material layer 2B is also formed on one side or both sides of the negative electrode current collector layer 2A. Further, when the negative electrode layer 2 is formed in the lowermost layer of the positive electrode layer 1 and the negative electrode layer 2 in the stacking direction of the stacked body 4, the negative electrode active material layer 2B in the lowermost negative electrode layer 2 is stacked in the stacking direction It only needs to be on one side of the upper side.
  • the positive electrode active material layer 1B and the negative electrode active material layer 2B include a positive electrode active material and a negative electrode active material that exchange electrons.
  • a conductive auxiliary agent, an ion conductive auxiliary agent, a binder and the like may be contained.
  • the positive electrode active material and the negative electrode active material are preferably capable of efficiently inserting and releasing lithium ions.
  • lithium vanadium phosphate which is a polyphosphoric acid compound, containing Li and V is used as the active material.
  • the active material material may be a simple substance of lithium vanadium phosphate, or may include a material other than lithium vanadium phosphate.
  • lithium phosphate can be used, for example.
  • the active material material preferably contains lithium vanadium phosphate in an amount of 90% by mass or more, and particularly preferably 95% by mass or more.
  • the a-axis length A, the b-axis length B, and the c-axis length C of the crystal axes satisfy all of the following formulas (1) to (3).
  • A represents the length of the a-axis in the crystal axis of lithium vanadium phosphate
  • A0 represents the a-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3.
  • B represents the length of the b-axis in the crystal axis of lithium vanadium phosphate
  • B0 represents the length of the b-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3.
  • C represents the length of the c-axis in the crystal axis of lithium vanadium phosphate
  • C0 represents the length of the c-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3 .
  • the unsubstituted Li 3 V 2 (PO 4 ) 3 is a stoichiometric lithium vanadium phosphate standard sample containing Li and V in a molar ratio of 3:2.
  • the lithium vanadium phosphate standard sample is prepared by firing a mixture containing LiPO 3 and V 2 O 3 in a molar ratio of 3:1 at a temperature of 850° C. for 2 hours in a solid phase reaction. It was obtained by.
  • the mixture was obtained by charging LiPO 3 and V 2 O 3 together with hard balls and methanol into a ball mill, mixing and pulverizing, and then drying.
  • As the reducing gas for example, a hydrogen-nitrogen mixed gas containing 3% hydrogen can be used.
  • the a-axis lengths A and A0, the b-axis lengths B and B0, the c-axis lengths C and C0 (lattice constants) of the crystal axes of the lithium vanadium phosphate and lithium vanadium phosphate standard samples of the present embodiment are , X-ray diffraction pattern is analyzed by Rietveld method. The lattice constant was determined by setting the space group of lithium vanadium phosphate as P21/C.
  • (A/A0) is the ratio of the length A of the a-axis in the crystal axis of lithium vanadium phosphate to the length A0 of the a-axis in the crystal axis of the lithium vanadium phosphate standard sample.
  • the larger (A/A0) indicates that the crystal lattice of lithium vanadium phosphate was expanded in the a-axis direction.
  • (A/A0) preferably satisfies 1 ⁇ (A/A0) ⁇ 1.0030, and particularly preferably 1.0012 ⁇ (A/A0) ⁇ 1.0030.
  • (B/B0) is the ratio of the b-axis length B of the lithium vanadium phosphate crystal axis to the b-axis length B0 of the lithium vanadium phosphate standard sample crystal axis.
  • the larger (B/B0) indicates that the crystal lattice of lithium vanadium phosphate was expanded in the b-axis direction.
  • (B/B0) preferably satisfies 1 ⁇ (B/B0) ⁇ 1.0051, and particularly preferably 1.0011 ⁇ (B/B0) ⁇ 1.051.
  • (C/C0) is the ratio of the length C of the c-axis in the crystal axis of lithium vanadium phosphate to the length C0 of the c-axis in the crystal axis of the lithium vanadium phosphate standard sample.
  • the larger (C/C0) indicates that the crystal lattice of lithium vanadium phosphate was greatly expanded in the c-axis direction.
  • (C/C0) preferably satisfies 1 ⁇ (C/C0) ⁇ 1.043, and particularly preferably 1.0010 ⁇ (C/C0) ⁇ 1.043.
  • the lithium ion conductivity of the positive electrode active material layer or the negative electrode active material layer can be improved, and by extension, the lithium ion secondary battery.
  • the discharge capacity of can be increased.
  • an active material in which a part of vanadium (V) in lithium vanadium phosphate is replaced with another element is preferable to use.
  • the substituting element is preferably any of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb, but is not particularly limited.
  • the substituting element may be one kind or a combination of two or more kinds.
  • lithium vanadium phosphate in which a part of V is substituted with at least one of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb is an active material Li 3 V 2 (with no element substitution).
  • Higher electron conductivity than that of PO 4 ) 3 can be obtained, which in turn improves the electron conductivity of the active material and can reduce the internal resistance of the all-solid-state battery.
  • the main phase of lithium vanadium phosphate is represented by the following general formula (I).
  • lithium phosphate can be mentioned, for example.
  • Lithium vanadium phosphate preferably contains the main phase in an amount of 90% by mass or more, and particularly preferably 95% by mass or more.
  • Li 3+a (V 2-x M x )(PO 4 ) 3 (I) (In the general formula (I), M represents at least one element selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb, and x is 0 ⁇ x ⁇ 0.3. Represents the number satisfied, and a represents the number satisfying ⁇ 3.0 ⁇ a ⁇ 3.0.)
  • the substitution amount is 0 as shown in formula (I).
  • the substitution amount x of the element M is larger than 0.3, element substitution may not be possible, a part of the substitution element may start to exist as a different phase, and eventually the ionic conductivity may be reduced.
  • the amount of Li in lithium vanadium phosphate is more preferably more than 0 mol and less than 6.0 mol.
  • the conductive aid examples include carbon materials such as carbon black, acetylene black, Ketjen black, carbon nanotubes, graphite, graphene and activated carbon, and metal materials such as gold, silver, palladium, platinum, copper and tin.
  • the ion-conducting aid is, for example, a solid electrolyte.
  • the solid electrolyte specifically, for example, the same material as the material used for the solid electrolyte 3 can be used.
  • a solid electrolyte is used as the ion-conducting auxiliary agent, it is preferable to use the same material as the ion-conducting auxiliary agent and the solid electrolyte used for the solid electrolyte 3.
  • the solid electrolyte 3 is preferably a phosphate-based solid electrolyte.
  • the solid electrolyte 3 it is preferable to use a material having a low electron conductivity and a high lithium ion conductivity.
  • perovskite type compounds such as La 0.5 Li 0.5 TiO 3
  • lithicon type compounds such as Li 14 Zn(GeO 4 ) 4
  • garnet type compounds such as Li 7 La 3 Zr 2 O 12 are used.
  • Nasicon type compounds such as Li 3.25 Ge 0.25 Thiolysicon type compounds such as P 0.75 S 4 and Li 3 PS 4
  • glass compounds such as Li 2 S—P 2 S 5 and Li 2 O—V 2 O 5 —SiO 2 , Li 3 PO 4 and Li 3.
  • At least one selected from the group consisting of phosphoric acid compounds such as 5 Si 0.5 P 0.5 O 4 and Li 2.9 PO 3.3 N 0.46 is desirable.
  • LiZr 2 (PO 4 ) 3 Li 1.3 Al 0.3 Ti 1.7
  • LiZr 2 (PO 4 ) 3 may substitute a part of Zr with Ca or Y. Examples thereof include Li 1.4 Ca 0.2 Zr 1.8 (PO 4 ) 3 and Li 1.15 Y 0.15 Zr 1.85 (PO 4 ) 3 .
  • the terminal electrodes 5 and 6 are formed in contact with the side surfaces (exposed surfaces of the end surfaces of the positive electrode layer 1 and the negative electrode layer 2) of the laminated body 4.
  • the terminal electrodes 5 and 6 are connected to external terminals and serve to transfer electrons to and from the stacked body 4.
  • terminal electrodes 5 and 6 It is preferable to use a material having high conductivity for the terminal electrodes 5 and 6.
  • a material having high conductivity for example, silver, gold, platinum, aluminum, copper, tin, nickel, gallium, indium, and alloys thereof can be used.
  • Lithium vanadium phosphate of this embodiment used as an active material of the all-solid-state battery 10 is a Li compound, a V compound, a phosphoric acid compound or a phosphoric acid Li compound and an yttrium compound, a gadolinium compound, a terbium compound, a dysprosium compound, It can be obtained by heat-treating a mixed raw material in which a holmium compound, an erbium compound, a thulium compound, and a ytterbium compound are mixed.
  • the lithium aluminum titanium phosphate material used as the solid electrolyte material of the all-solid-state battery 10 is obtained by heat-treating a mixed raw material in which a Li compound is mixed with an Al compound, a Ti compound, a phosphoric acid compound, or a Ti phosphate compound. Can be obtained by
  • Examples of the Li compound include LiOH or a hydrate thereof, Li 2 CO 3 , LiNO 3 , CH 3 COOLi, and the like.
  • Examples of the V compound include V 2 O 3 and V 2 O 5 .
  • Examples of the phosphorus compound include H 3 PO 4 , NH 4 H 2 PO 4 , (NH 4 ) 2 HPO 4, and the like.
  • As the phosphoric acid Li compound mention may be made of LiPO 3, Li 4 P 2 O 7, Li 5 P 3 O 10, Li 6 P 4 O 14 and the like.
  • yttrium compounds, gadolinium compounds, terbium compounds, dysprosium compounds, holmium compounds, erbium compounds, thulium compounds, and ytterbium compounds include Y 2 O 3 , Gd 2 O 3 , Tb 2 O 3 , Dy 2 O 3 , and Ho 2 O. 3, Er 2 O 3, Tm 2 O 3, Yb 2 O 3 and the like.
  • Al compounds include Al 2 O 3 , Al(OH) 3 , and Al 2 (SO 4 ) 3 .
  • the Ti compound include TiO 2 , Ti 2 O 3 , TiCl 4 , and Ti(OR) 4 .
  • Ti phosphate compound examples include TiP 2 O 7 and Ti 3 P 4 O 16 .
  • (A) Raw Material Mixing Step In the raw material mixing step, starting materials of lithium vanadium phosphate are weighed and mixed so as to have a desired composition.
  • the starting material carbonates, sulfates, nitrates, oxalates, chlorides, hydroxides, oxides, phosphates of each element can be used.
  • the raw materials and oxides already obtained as lithium phosphate are preferable because there is no generation of unnecessary gas for heat treatment, and further, carbonates that generate carbon dioxide and hydroxides that thermally decompose to generate water vapor are preferable.
  • the mixing method may be dry-mixing and pulverizing without putting in a solvent, or wet mixing and pulverizing in a solvent.
  • performing wet mixing and pulverizing in a solvent may improve the mixing property. From the aspect, it is preferable.
  • the mixing method for example, a planetary mill, an attritor, a ball mill or the like can be used.
  • the solvent a solvent in which Li is difficult to dissolve is preferable, and an organic solvent such as ethanol is more preferable.
  • the mixing time may be, for example, 1 hour to 32 hours, depending on the mixing amount. Further, in the case of lithium aluminum aluminum phosphate, the starting materials are weighed so as to have a desired composition and mixed by any method.
  • the calcination temperature at this time is preferably a temperature at which the state change (for example, phase change) of the starting material occurs or higher.
  • the temperature is preferably higher than the temperature at which this carbonate is decomposed and a desired lithium vanadium phosphate phase is formed.
  • the calcination temperature is preferably 600°C to 1000°C.
  • the atmosphere during calcination is preferably an inert gas atmosphere or a reducing gas atmosphere.
  • the inert gas for example, nitrogen gas or argon gas can be used.
  • a mixed gas containing hydrogen gas and an inert gas can be used.
  • the hydrogen concentration of the mixed gas is preferably in the range of 0.1% by volume or more and 5% by volume or less.
  • the hydrogen gas concentration of the mixed gas may be changed in order to control the amount of trivalent V in V in lithium vanadium phosphate.
  • the hydrogen concentration of the mixed gas may be as high as 5% by volume at the start of firing and as low as 0.1% by volume at the end of firing.
  • the mixed powder obtained in the mixing step is also calcined.
  • the calcination temperature is preferably 800°C to 1000°C.
  • the atmosphere during the calcination is preferably an atmosphere in which titanium is not reduced, and specifically, an air atmosphere is preferable.
  • the pulverizing step the material reactively aggregated in the calcination step is converted into a powder having an appropriate particle size and distribution.
  • the pulverization method may be dry pulverization without adding it to a solvent, or wet pulverization with addition to a solvent.
  • a solvent for example, a planetary mill, an attritor, a ball mill or the like can be used.
  • the solvent an organic solvent such as ethanol is more preferable because lithium vanadium phosphate can be ground more stably.
  • the crushing time may be, for example, 0.5 hour to 32 hours, depending on the crushing amount.
  • the manufacturing method described in detail above since the mixed powder of the starting materials is calcined at a relatively low temperature, it is possible to accurately suppress the composition deviation.
  • the manufacturing method of lithium vanadium phosphate is not limited to this, and other manufacturing methods may be adopted.
  • the lithium vanadium phosphate according to this embodiment has high ionic conductivity.
  • a method for evaluating the ionic conductivity of lithium vanadium phosphate will be described.
  • the method for evaluating the ionic conductivity of lithium vanadium phosphate includes, for example, (d) a molding step, (e) a binder removal and firing step, and (f) an ionic conductivity evaluation step.
  • (D) Forming Step In the forming step, after the material obtained in the calcination step (referred to as pre-sintering powder) is formed, sintering is performed at a temperature higher than the calcination temperature.
  • a molding method for obtaining a molded body a method of adding a binder to the pre-sintering powder to perform mold molding, cold isotropic molding (CIP), hot isotropic molding (HIP), hot pressing, etc. It can be performed in any shape.
  • the powder before sintering may be mixed with an organic binder, a dispersant, a plasticizer, etc., and molded into a sheet to form a multilayer structure.
  • (E) Debinding and firing process When using a binder, the debinding is performed in nitrogen or in a reducing gas atmosphere at a heating rate of 10°C/hour to 500°C/hour, and the debinding temperature is 500°C to 900°C. Then, the temperature is maintained for 1 to 10 hours.
  • the firing is performed in nitrogen or in a reducing gas atmosphere at a heating rate of 50° C./hour to 3600° C./hour, the firing temperature is raised from 700° C. to 1200° C., and the temperature is kept for 10 minutes to 5 hours to cool. To do.
  • Electrodes are formed on both sides of the plate-shaped fired body obtained in the firing step.
  • the electrodes may be Cu, Ag, Au, Pd or the like, and as a forming method, a paste baking method, a vapor deposition method or a sputtering method may be used.
  • the material on which the electrodes are formed is measured in impedance and phase angle with respect to frequency with the measurement temperature kept constant using an AC impedance analyzer in a constant temperature bath. Based on these measured values, a Nyquist plot is drawn, the resistance value is obtained from the arc, and the conductivity is calculated from this resistance value.
  • the all-solid-state battery of the present embodiment the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and each material of the negative electrode current collector layer is made into a paste, coated and dried to form a green sheet. It is manufactured by stacking the manufactured green sheets and firing the manufactured stack at the same time.
  • the method of forming a paste is not particularly limited, but for example, a paste can be obtained by mixing a vehicle with powders of the above materials.
  • the vehicle is a general term for a medium in a liquid phase.
  • the vehicle includes a solvent and a binder.
  • the method of applying the paste is not particularly limited, and known methods such as screen printing, application, transfer, doctor blade, etc. can be adopted.
  • the active material unit described below may be prepared and the laminated block may be manufactured.
  • the method is to first form a solid electrolyte layer paste on a PET film into a sheet by a doctor blade method, obtain a solid electrolyte sheet, and then paste the positive electrode active material layer paste by screen printing on the solid electrolyte sheet. Print and dry. Then, a positive electrode current collector layer paste is printed thereon by screen printing and dried. Further, a positive electrode active material layer paste is printed again by screen printing, dried, and then the PET film is peeled off to obtain a positive electrode active material layer unit. In this way, a positive electrode active material layer unit is obtained in which the positive electrode active material layer paste, the positive electrode current collector layer paste, and the positive electrode active material layer paste are formed in this order on the solid electrolyte sheet.
  • a negative electrode active material layer unit was also produced by the same procedure, and a negative electrode active material layer paste, a negative electrode current collector layer paste, and a negative electrode active material layer paste were formed in this order on a solid electrolyte sheet. Get a layer unit.
  • the pressure bonding is performed while heating, and the heating temperature is, for example, 40 to 95°C.
  • the pressure-bonded laminated block is heated to, for example, 600°C to 1100°C in a nitrogen gas atmosphere and fired.
  • the firing time is, for example, 0.1 to 3 hours. This firing completes the laminated body.
  • the second embodiment relates to a lithium secondary battery that does not use a solid electrolyte. Since the same active material as in the first embodiment is used as the active material in the present embodiment, duplicate description will be omitted after describing it.
  • the lithium-ion secondary battery 100 is arranged adjacent to each other between the plate-shaped negative electrode 21 and the plate-shaped positive electrode 11, which face each other, and the negative electrode 21 and the positive electrode 11.
  • a power generation element 30 including a plate-shaped separator 18 that has a plate-like separator, an electrolyte solution containing lithium ions, a case 50 that houses these in a sealed state, and one end of the negative electrode 21 is electrically connected and
  • the negative electrode lead 62 has the other end protruding outside the case, and the positive electrode lead 60 has one end electrically connected to the positive electrode 11 and the other end protruding outside the case. ..
  • the negative electrode 21 has a negative electrode current collector 22 and a negative electrode active material layer 24 formed on the negative electrode current collector 22.
  • the positive electrode 11 has a positive electrode current collector 12 and a positive electrode active material layer 14 formed on the positive electrode current collector 12.
  • the separator 18 is located between the negative electrode active material layer 24 and the positive electrode active material layer 14.
  • the positive electrode active material layer 14 and the negative electrode active material layer 24 include an active material, a conductive additive, and a binder.
  • the lithium vanadium phosphate described in the first embodiment can be used as the active material.
  • This lithium vanadium phosphate may be used in either one of the positive electrode active material layer and the negative electrode active material layer, or may be used in both.
  • Example 1 (Preparation of active material)
  • the raw materials were weighed so that lithium vanadium phosphate had Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 .
  • LiPO 3 , V 2 O 3 , and Yb 2 O 3 were used as starting materials.
  • the mixed powder of the starting materials was separated from the balls and ethanol, dried, and then calcined using a magnesia crucible. The calcination was performed in a reducing gas atmosphere at 950° C.
  • the reducing gas a mixed gas of nitrogen gas and hydrogen gas was used, and the calcination was started at a hydrogen gas concentration of 5% by volume and continuously changed to 0.1% by volume. Then, the calcined powder was treated with a ball mill (120 rpm/zirconia ball) for 16 hours in ethanol for pulverization. The ground powder was separated from the balls and ethanol and dried to obtain lithium vanadium phosphate powder in which ytterbium was substituted at the vanadium position.
  • the composition of the ytterbium-substituted lithium vanadium phosphate was confirmed using ICP emission spectroscopy. Further, the lattice constants of the ytterbium-substituted lithium vanadium phosphate (a-axis length A, b-axis length B and c-axis length C) were 2 ⁇ obtained from an X-ray diffraction pattern measured by an X-ray diffraction method. And calculated from the strength data using the Rietveld method. The measurement conditions of the X-ray diffraction pattern are as follows.
  • LiPO 3 and V 2 O 3 were used as starting materials. LiPO 3 and V 2 O 3 were weighed in a molar ratio of 3:1. The weighed LiPO 3 and V 2 O 3 were put into a ball mill together with hard balls (zirconia balls) and methanol, and mixed and pulverized. Then the mixture was separated from methanol and dried. The dried mixture was baked at a temperature of 850° C. for 2 hours under a hydrogen-nitrogen mixed gas atmosphere containing 3% hydrogen. Then, the fired powder was treated with a ball mill (120 rpm/zirconia ball) in ethanol for 16 hours for pulverization.
  • a ball mill 120 rpm/zirconia ball
  • the ground powder was separated from the balls and ethanol and dried to obtain a lithium vanadium phosphate standard sample.
  • the composition of the lithium vanadium phosphate standard sample was confirmed by ICP emission spectroscopy, it was confirmed to be an unsubstituted lithium vanadium phosphate containing Li and V in a molar ratio of 3:2. ..
  • 2 ⁇ and intensity data were measured by the X-ray diffraction method, and the Rietveld method was used to measure the lattice constants (a-axis length A0, b-axis length B0 and c-axis).
  • the length C0 was calculated.
  • the a-axis length A0 was 8.6085 ⁇
  • the b-axis length B0 was 8.5941 ⁇
  • the c-axis length C0 was 14.72667 ⁇ .
  • the lattice constants (a-axis length A, b-axis length B and c-axis length C) of the obtained ytterbium-substituted lithium vanadium phosphate, and the lattice constants of the lithium vanadium phosphate standard sample (a-axis length) (A/A0), (B/B0), and (C/C0) were calculated using the length A0, the b-axis length B0, and the c-axis length C0).
  • Table 1 shows (A/A0) as the a-axis magnification, (B/B0) as the b-axis magnification, and (C/C0) as the c-axis magnification.
  • the ytterbium-substituted lithium vanadium phosphate powder produced in Example 1 was pressure-molded into a circular pellet having a diameter of 10 mm under a pressure of 3.5 Mpa, and the pressure-molded body was heated in a nitrogen gas atmosphere at a temperature of 975° C. for 2 hours. By firing, a ytterbium-substituted lithium vanadium phosphate sintered body was obtained. Gold electrodes were formed on both surfaces of this pellet-shaped sintered body by a sputtering method.
  • the impedance and phase angle with respect to frequency were measured for the sintered body using an AC impedance analyzer in a constant temperature bath under the condition of a measurement temperature of 25°C. Based on these measured values, a Nyquist plot was drawn, the resistivity was determined from the arc, and the ionic conductivity was calculated from this resistivity. The obtained ionic conductivity is shown in Table 1.
  • the positive electrode and negative electrode active material layer paste is 100 parts of ytterbium-substituted lithium vanadium phosphate powder, 15 parts of ethyl cellulose as a binder, and 65 parts of dihydroterpineol as a solvent are added, and the mixture is kneaded and dispersed with a three-roll roll to form a positive electrode. And the paste for active material layers used as a negative electrode was produced.
  • This solid electrolyte layer paste was formed into a sheet by a doctor blade method using a PET film as a base material to obtain a solid electrolyte layer sheet having a thickness of 15 ⁇ m.
  • An electrode current collector layer paste having a thickness of 5 ⁇ m was printed on the above solid electrolyte layer sheet by screen printing and dried at 80° C. for 10 minutes. Then, a positive electrode active material layer paste having a thickness of 5 ⁇ m was printed by screen printing and dried at 80° C. for 10 minutes to obtain a positive electrode layer unit.
  • a paste for negative electrode active material layer having a thickness of 5 ⁇ m is printed by screen printing on a sheet for solid electrolyte layer, dried at 80° C. for 10 minutes, and then an electrode having a thickness of 5 ⁇ m is printed by screen printing. The current collector layer paste was printed and dried at 80° C. for 10 minutes to obtain a negative electrode layer unit. Then, the PET film was peeled off.
  • a solid electrolyte layer, a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, a negative electrode current collector layer, a solid electrolyte layer A stacked laminate was obtained so as to be formed in the order of.
  • the units are stacked in a staggered manner so that the positive electrode current collector layer of the positive electrode layer unit extends only on one end face and the negative electrode current collector layer of the negative electrode active material layer unit extends only on the other end face. It was Then, this was molded by thermocompression bonding and then cut to prepare a laminate.
  • the sintered body (all-solid-state battery) of the obtained laminated body was attached to a jig of a type fixed with a spring-loaded pin using a charge/discharge tester, and the charge/discharge capacity was measured.
  • the current during charging/discharging was 2 ⁇ A
  • the voltage was 0 V to 1.8 V.
  • Table 1 shows the measured discharge capacity.
  • the threshold value of the discharge characteristic sufficient for use is 3.6 ⁇ Ah.
  • Examples 2 to 23 Comparative Examples 1 to 9
  • a sintered body was produced under the same conditions and methods as in Example 1 except that the composition and raw material of the active material of interest were those described in Tables 1 and 2, and the same.
  • Various values were evaluated according to the conditions and method. The results are shown in Tables 1 and 2.
  • a is the value of a in the general formula (I).
  • Example 24 (Preparation of organic solvent electrolyte battery) ⁇ Production of positive electrode> A positive electrode was produced using Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 produced in Example 1 as the positive electrode active material.
  • Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 85 g, carbon black (manufactured by Denki Kagaku Kogyo KK, DAB50) 5 g, graphite (Timcal KK, trade name: KS-6) 5 g of polyvinylidene fluoride (PVDF) solution of binder (Kureha Chemical Industry Co., Ltd., trade name: KF7305, NMP solution containing 5% by mass of PVDF) was weighed in a resin container and mixed with a hybrid mixer.
  • PVDF polyvinylidene fluoride
  • a paint was prepared. This paint was applied to an aluminum foil (thickness 20 ⁇ m) as a current collector by the doctor blade method, dried at 90° C., and rolled. In addition, in order to weld the external lead terminal (lead), the current collector was provided with a portion to which no paint was applied.
  • a negative electrode was produced using Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 produced in Example 1 as the negative electrode active material.
  • Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 carbon black (DAB50 manufactured by Denki Kagaku Kogyo Co., Ltd.), and 10 g, 0.231 g, and 7% of 15 mass% aqueous solutions of polyacrylic acid as a binder, respectively.
  • a 584 g resin container was weighed and mixed with a stirrer (manufactured by KEYENCE CORPORATION, product name: hybrid mixer) that revolves around its axis to prepare a coating material.
  • This paint was applied to a copper foil (thickness 10 ⁇ m) as a current collector by the doctor blade method, dried at 90° C., and rolled at a linear pressure of 600 kgf/cm.
  • This negative electrode was heat-treated in a vacuum atmosphere at 150° C. for 20 hours.
  • the current collector was provided with a portion to which no paint was applied.
  • the positive electrode, the negative electrode, and the separator (microporous film made of polyolefin) produced as described above were cut into predetermined dimensions. Then, the positive electrode, the negative electrode, and the separator were laminated in this order. At the time of stacking, a small amount of hot melt adhesive (ethylene-methacrylic acid copolymer) was applied and fixed so that the positive electrode, the negative electrode, and the separator were not displaced. An aluminum foil and a nickel foil were ultrasonically welded to the positive electrode and the negative electrode as external lead terminals, respectively.
  • hot melt adhesive ethylene-methacrylic acid copolymer
  • polypropylene (PP) grafted with maleic anhydride was wrapped around and thermally bonded to the external lead terminal.
  • the battery exterior body enclosing the battery element in which the positive electrode, the negative electrode, and the separator were laminated was made of an aluminum laminate material, and the composition thereof was PET/Al/PP (PET is an abbreviation for polyethylene terephthalate). At this time, the bag was made so that PP was on the inside.
  • electrolyte solution a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC:30:70 vol %)
  • the charge/discharge test was conducted in a constant temperature bath at 25° C., the current during charge/discharge was 2 ⁇ A, and the voltage was 0.5 V to 1.8 V.
  • the measured discharge capacity was 7.1 ⁇ Ah.
  • the threshold value of the discharge characteristic sufficient for use is 3.6 ⁇ Ah.
  • Example 10 A lithium ion secondary battery was produced under the same conditions and method as in Example 24, except that the positive electrode and the negative electrode were produced using Li 3 V 2 (PO 4 ) 3 produced in Comparative Example 1 as the active material. The discharge capacity was measured in the same manner as in 24. The measured discharge capacity was 3.4 ⁇ Ah.
  • the battery according to the present invention is effective in improving the discharge capacity. Providing a high-capacity battery makes a great contribution, especially in the field of electronics.

Abstract

This active material comprises vanadium lithium phosphate that is a polyphosphate compound, said vanadium lithium phosphate satisfying all of requirements (1) to (3).　1<(A/A0)≤1.0030 (1) 1<(B/B0)≤1.0051 (2) 1<(C/C0)≤1.0043 (3) In requirements (1) to (3): A stands for the length of the axis a in the crystal axes of the vanadium lithium phosphate; A0 stands for the length of the axis a in the crystal axes of unsubstituted Li3V2(PO4)3; B stands for the length of the axis b in the crystal axes of the vanadium lithium phosphate; B0 stands for the length of the axis b in the crystal axes of unsubstituted Li3V2(PO4)3; C stands for the length of the axis c in the crystal axes of the vanadium lithium phosphate; and C0 stands for the length of the axis c in the crystal axes of unsubstituted Li3V2(PO4)3.

Description

活物質材料および全固体電池Active material and all solid state battery
　本発明は、二次電池用の活物質材料およびこれを用いた二次電池に関する。
　本願は、２０１８年１２月１７日に、日本に出願された特願２０１８－２３５０９１号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to an active material material for a secondary battery and a secondary battery using the same.
The present application claims priority based on Japanese Patent Application No. 2018-235091, filed in Japan on December 17, 2018, the contents of which are incorporated herein by reference.
　近年、高温においても結晶安定性及び熱的安定性に優れた活物質として、ポリリン酸系活物質が検討されている。 In recent years, polyphosphoric acid-based active materials have been investigated as active materials having excellent crystal stability and thermal stability even at high temperatures.
　このようなポリリン酸系活物質として、オリビン構造を有するリン酸鉄リチウム（ＬｉＦｅＰＯ４）の研究が盛んに行われている。しかし、リン酸鉄リチウムはその結晶構造特有の電気伝導性やリチウムイオン伝導性の低さに由来する活物質の利用率及び高率充放電性能の低さのため、従来のリチウム含有遷移金属化合物に比べて入出力性能が低下する。そこで、約４Ｖ（ｖｓ．Ｌｉ／Ｌｉ＋）付近に可逆電位を有するリン酸バナジウムリチウム（Ｌｉ３Ｖ２（ＰＯ４）３）の検討が行われている。 As such a polyphosphoric acid-based active material, research on lithium iron phosphate (LiFePO 4 ) having an olivine structure has been actively conducted. However, lithium iron phosphate is a conventional lithium-containing transition metal compound because of its low utilization rate and high rate charge/discharge performance of the active material derived from its low electric conductivity and lithium ion conductivity peculiar to its crystal structure. I/O performance is lower than that of. Therefore, studies have been conducted on lithium vanadium phosphate (Li 3 V 2 (PO 4 ) 3 ) having a reversible potential in the vicinity of about 4 V (vs. Li/Li + ).
　リン酸バナジウムリチウム（Ｌｉ３Ｖ２（ＰＯ４）３）は、複数の酸化還元電位（３．８Ｖ、１．８Ｖ）を持つために、Ｌｉ３Ｖ２（ＰＯ４）３を正極、負極に用いた対称電極電池においては、約２Ｖ級の電池の実現が可能になる。 Lithium vanadium phosphate (Li 3 V 2 (PO 4 ) 3 ) has a plurality of redox potentials (3.8 V, 1.8 V), and therefore Li 3 V 2 (PO 4 ) 3 is used as a positive electrode and a negative electrode. The symmetrical electrode battery used can realize a battery of about 2V class.
　しかしながら、より高い出力特性や、特に全固体電池におけるより高い放電容量を得るためには活物質中のリチウムイオン伝導度を高くする必要がある。 However, it is necessary to increase the lithium ion conductivity in the active material in order to obtain higher output characteristics and especially higher discharge capacity in all-solid-state batteries.
　そこで、特許文献１において、Ｌｉ３Ｖ２（ＰＯ４）３に対して、Ｖサイトを他の金属元素を置換するが報告されているが、Ｌｉ３Ｖ２（ＰＯ４）３以外、他の金属元素を置換した実施例は明記されていない。 Therefore, in Patent Document 1, with respect to Li 3 V 2 (PO 4) 3, but is to replace the other metal element V site has been reported, Li 3 V 2 (PO 4 ) 3 than, the other Examples in which the metal element is replaced are not specified.
　また、特許文献２には、Ｌｉ３Ｖ２（ＰＯ４）３に対してバナジウムサイトをマンガンで置換することで、高い放充効率特性が得られる事は報告されているが、高い放電容量についての言及が無く、さらにイオン伝導度についての記載も無い。 Further, Patent Document 2 reports that by substituting the vanadium site with respect to Li 3 V 2 (PO 4 ) 3 with manganese, high discharge efficiency characteristics can be obtained. Is not mentioned, and there is no description about ionic conductivity.
　さらに、特許文献３では、Ｌｉ３Ｖ２（ＰＯ４）３に対してバナジウムサイトをアルミニウム、チタニウム、ジルコニウムで置換する事でイオン伝導度の高い高温相を室温下で安定化することによって容量特性が向上できるという報告があるが、希土類元素での置換や置換に伴う格子定数の増加が容量特性を向上させる記載は無い。 Further, in Patent Document 3, by replacing the vanadium site with respect to Li 3 V 2 (PO 4 ) 3 by aluminum, titanium, and zirconium, the high-temperature phase having high ionic conductivity is stabilized at room temperature to thereby obtain a capacitive characteristic. However, there is no description that substitution with a rare earth element or an increase in the lattice constant associated with the substitution improves the capacitance characteristics.
特許第４２９２３１７号公報Japanese Patent No. 4292317 特許第５８６２１７２号公報Patent No. 5862172 特許第２９４９２２９号公報Japanese Patent No. 2949229
　本発明はこのような従来技術の有する問題点に鑑みてなされたものであり、その課題とするところは、活物質のイオン伝導度を高くすることで、高い放電容量を有する電池を提供することにある。 The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a battery having a high discharge capacity by increasing the ionic conductivity of an active material. It is in.
　本発明者らは、上記課題を達成すべく鋭意検討した結果、Ｌｉ３Ｖ２（ＰＯ４）３のＶサイトに元素置換を行い、結晶格子を広げることで、リチウムイオンが動き易くなり、イオン伝導度が高くなることで放電容量が高くなることを見出した。 As a result of earnest studies to achieve the above-mentioned problems, the present inventors performed element substitution on the V site of Li 3 V 2 (PO 4 ) 3 and widened the crystal lattice, so that lithium ions became easy to move, It was found that the higher the conductivity, the higher the discharge capacity.
　即ち、本発明の一態様によれば、以下に示す活物質材料、および全固体電池が提供される。 That is, according to one aspect of the present invention, the following active material and all-solid-state battery are provided.
　本発明の一態様に係る活物質材料は、ポリリン酸化合物であるリン酸バナジウムリチウムを含み、
　前記リン酸バナジウムリチウムは下記の式（１）～（３）の全てを満たす。
　１＜（Ａ／Ａ０）≦１．００３０　（１）
　１＜（Ｂ／Ｂ０）≦１．００５１　（２）
　１＜（Ｃ／Ｃ０）≦１．００４３　（３）
　式（１）～（３）において、Ａは、前記リン酸バナジウムリチウムの結晶軸におけるａ軸の長さを表し、Ａ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるａ軸の長さを表し、Ｂは、前記リン酸バナジウムリチウムの結晶軸におけるｂ軸の長さを表し、Ｂ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるｂ軸の長さを表し、Ｃは、前記リン酸バナジウムリチウムの結晶軸におけるｃ軸の長さを表し、Ｃ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるｃ軸の長さを表す。 The active material material according to one embodiment of the present invention includes lithium vanadium phosphate that is a polyphosphoric acid compound,
The lithium vanadium phosphate satisfies all of the following formulas (1) to (3).
1 <(A/A0) ≤ 1.0030 (1)
1<(B/B0)≦1.0051 (2)
1<(C/C0)≦1.043 (3)
In formulas (1) to (3), A represents the length of the a-axis in the crystal axis of the lithium vanadium phosphate, and A0 represents a in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. Represents the length of the axis, B represents the length of the b axis in the crystal axis of the lithium vanadium phosphate, and B0 represents the length of the b axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. C represents the length of the c-axis in the crystal axis of the lithium vanadium phosphate, and C0 represents the length of the c-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. ..
　係る構成の活物質材料を用いることにより、リチウムイオン二次電池の放電容量を高くすることができる。これは、Ｌｉ３Ｖ２（ＰＯ４）３の結晶軸におけるａ軸、ｂ軸、ｃ軸の各軸の長さが上記の範囲になることにより、結晶中にリチウムイオンの移動しやすい空間が形成され、リチウムイオン伝導度が高くなったためと考えられる。 By using the active material material having such a configuration, the discharge capacity of the lithium ion secondary battery can be increased. This is because the length of each of the a-axis, the b-axis, and the c-axis of the crystal axes of Li 3 V 2 (PO 4 ) 3 falls within the above range, so that a space where lithium ions easily move is formed in the crystal. It is thought that this is because the lithium ion conductivity was increased and the lithium ion conductivity was increased.
　上記の態様に係る活物質材料において、前記リン酸バナジウムリチウムは、バナジウムの一部が、Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂからなる群より選ばれる少なくとも一つの元素で置換されていることが好ましい。 In the active material material according to the above aspect, in the vanadium lithium phosphate, part of vanadium is replaced with at least one element selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb. Is preferably provided.
　係る構成によれば、バナジウム（Ｖ）の一部への置換量を最適なものとできる。 With such a configuration, the amount of vanadium (V) to be partially replaced can be optimized.
　上記の態様に係る活物質材料において、前記リン酸バナジウムリチウムの主相が、下記の一般式（Ｉ）を満たす、活物質材料とすることが更に好ましい。
　Ｌｉ３＋ａ（Ｖ２－ｘＭｘ）（ＰＯ４）３　（Ｉ）
　一般式（Ｉ）において、Ｍは、Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂからなる群より選ばれる少なくとも一つの元素を表し、ｘは、０＜ｘ≦０．３を満たす数を表し、ａは、－３．０＜ａ＜３．０を満たす数を表す。 In the active material material according to the above aspect, it is more preferable to use an active material material in which the main phase of the lithium vanadium phosphate satisfies the following general formula (I).
Li 3+a (V 2-x M x )(PO 4 ) 3 (I)
In the general formula (I), M represents at least one element selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb, and x satisfies 0<x≦0.3. Represents a number, and a represents a number satisfying −3.0<a<3.0.
　係る構成によれば、より容易に上述の式（１）～（３）に記載の結晶軸長を形成することができる。 With this configuration, it is possible to more easily form the crystal axis lengths described in the above formulas (1) to (3).
　本発明の一態様に係る全固体電池は、上述の活物質材料を含む電極層と、固体電解質層とを備える。 An all-solid-state battery according to one aspect of the present invention includes an electrode layer containing the above-mentioned active material and a solid electrolyte layer.
　係る構成によれば、より高容量の全固体電池が得られる。 With such a configuration, a higher capacity all-solid-state battery can be obtained.
　本発明によれば、高い放電容量を得ることができる優れたリチウムイオン二次電池用活物質材料、特に全固体電池用活物質材料、および全固体電池を提供することができる。 According to the present invention, it is possible to provide an excellent active material material for a lithium-ion secondary battery capable of obtaining a high discharge capacity, particularly an active material material for an all-solid-state battery, and an all-solid-state battery.
第１実施形態の全固体電池の模式断面図を示す。The schematic cross section of the all-solid-state battery of 1st Embodiment is shown. 第２実施形態のリチウム二次電池の模式断面図を示す。The schematic cross section of the lithium secondary battery of 2nd Embodiment is shown.
　以下、本発明の種々の実施形態に係る活物質材料を用いた二次電池について、図を適宜参照しながら詳細に説明する。以下の説明で用いる図面は、本発明の特徴をわかりやすくするために便宜上特徴となる部分を拡大して示している場合がある。したがって、図面に記載の各構成要素の寸法比率などは、実際とは異なっていることがある。以下の説明において例示される材料、寸法等は一例であって、本発明はそれらに限定されるものではなく、その要旨を変更しない範囲で適宜変更して実施できる。 Hereinafter, secondary batteries using active material materials according to various embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the drawings used in the following description, in order to make the features of the present invention easier to understand, the features may be enlarged for convenience. Therefore, the dimensional ratio of each constituent element illustrated in the drawings may be different from the actual one. The materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to them, and can be appropriately modified and implemented without changing the gist thereof.
［第１実施形態］
　第１実施形態は、全固体電池（全固体二次電池）に係る。全固体電池１０は、少なくとも一つの正極層１と、少なくとも一つの負極層２と、正極層１と負極層２とに挟まれた固体電解質３とを有する。正極層１、固体電解質３及び負極層２が順に積層されて積層体４を構成する。正極層１は、それぞれ一端側に配設された端子電極５に接続され、負極層２は、それぞれ他端側に配設された端子電極６に接続されている。 [First Embodiment]
The first embodiment relates to an all solid state battery (all solid state secondary battery). The all-solid-state battery 10 has at least one positive electrode layer 1, at least one negative electrode layer 2, and a solid electrolyte 3 sandwiched between the positive electrode layer 1 and the negative electrode layer 2. The positive electrode layer 1, the solid electrolyte 3, and the negative electrode layer 2 are sequentially laminated to form a laminated body 4. The positive electrode layer 1 is connected to a terminal electrode 5 arranged on one end side, and the negative electrode layer 2 is connected to a terminal electrode 6 arranged on the other end side.
　正極層１は、第１電極層の一例であり、負極層２は、第２電極層の一例である。第１電極層と第２電極層は、いずれか一方が正極として機能し、他方が負極として機能する。電極層の正負は、外部端子にいずれの極性を繋ぐかによって変化する。 The positive electrode layer 1 is an example of a first electrode layer, and the negative electrode layer 2 is an example of a second electrode layer. One of the first electrode layer and the second electrode layer functions as a positive electrode and the other functions as a negative electrode. The positive/negative of the electrode layer changes depending on which polarity is connected to the external terminal.
　図１に示すように、正極層１と負極層２は、固体電解質３を介して交互に積層されている。正極層１と負極層２の間で固体電解質３を介したリチウムイオンの授受により、全固体電池１０の充放電が行われる。 As shown in FIG. 1, the positive electrode layer 1 and the negative electrode layer 2 are alternately laminated with the solid electrolyte 3 interposed therebetween. The all-solid-state battery 10 is charged and discharged by exchanging lithium ions between the positive electrode layer 1 and the negative electrode layer 2 via the solid electrolyte 3.
＜正極層及び負極層＞
　正極層１は、正極集電体層１Ａと、正極活物質を含む正極活物質層１Ｂとを有する。負極層２は、負極集電体層２Ａと、負極活物質を含む負極活物質層２Ｂとを有する。 <Positive electrode layer and negative electrode layer>
The positive electrode layer 1 has a positive electrode current collector layer 1A and a positive electrode active material layer 1B containing a positive electrode active material. The negative electrode layer 2 has a negative electrode current collector layer 2A and a negative electrode active material layer 2B containing a negative electrode active material.
　正極集電体層１Ａ及び負極集電体層２Ａは、導電率が高いことが好ましい。そのため、正極集電体層１Ａ及び負極集電体層２Ａには、例えば、銀、パラジウム、金、プラチナ、アルミニウム、銅、ニッケル等を用いることが好ましい。これらの物質の中でも、銅は正極活物質、負極活物質及び固体電解質と反応しにくい。そのため、正極集電体層１Ａ及び負極集電体層２Ａに銅を用いると、全固体電池１０の内部抵抗を低減できる。なお、正極集電体層１Ａと負極集電体層２Ａを構成する物質は、同一でもよいし、異なってもよい。 The positive electrode current collector layer 1A and the negative electrode current collector layer 2A preferably have high conductivity. Therefore, it is preferable to use, for example, silver, palladium, gold, platinum, aluminum, copper, nickel or the like for the positive electrode current collector layer 1A and the negative electrode current collector layer 2A. Among these substances, copper hardly reacts with the positive electrode active material, the negative electrode active material and the solid electrolyte. Therefore, if copper is used for the positive electrode current collector layer 1A and the negative electrode current collector layer 2A, the internal resistance of the all-solid-state battery 10 can be reduced. The materials forming the positive electrode current collector layer 1A and the negative electrode current collector layer 2A may be the same or different.
　また、本実施形態における全固体電池１０の正極集電体層１Ａ及び負極集電体層２Ａは、それぞれ後述する活物質材料を含ませることができる。正極集電体層１Ａ及び負極集電体層２Ａがそれぞれ活物質材料を含むことにより、正極集電体層１Ａと正極活物質層１Ｂ及び負極集電体層２Ａと負極活物質層２Ｂとの密着性を向上させることができる。 Further, each of the positive electrode current collector layer 1A and the negative electrode current collector layer 2A of the all-solid-state battery 10 in the present embodiment can include an active material material described below. Since the positive electrode current collector layer 1A and the negative electrode current collector layer 2A each contain an active material, the positive electrode current collector layer 1A and the positive electrode active material layer 1B and the negative electrode current collector layer 2A and the negative electrode active material layer 2B are formed. Adhesion can be improved.
　正極活物質層１Ｂは、正極集電体層１Ａの片面又は両面に形成される。例えば、正極層１と負極層２のうち、積層体４の積層方向の最上層に正極層１が形成されている場合、最上層に位置する正極層１の上には対向する負極層２が無い。そのため、最上層に位置する正極層１において正極活物質層１Ｂは、積層方向下側の片面のみにあればよい。 The positive electrode active material layer 1B is formed on one side or both sides of the positive electrode current collector layer 1A. For example, when the positive electrode layer 1 is formed on the uppermost layer of the positive electrode layer 1 and the negative electrode layer 2 in the stacking direction of the laminated body 4, the opposing negative electrode layer 2 is formed on the uppermost positive electrode layer 1. There is no. Therefore, the positive electrode active material layer 1B in the positive electrode layer 1 located at the uppermost layer may be provided on only one surface on the lower side in the stacking direction.
　負極活物質層２Ｂも正極活物質層１Ｂと同様に、負極集電体層２Ａの片面又は両面に形成される。また、正極層１と負極層２のうち、積層体４の積層方向の最下層に負極層２が形成されている場合、最下層に位置する負極層２において負極活物質層２Ｂは、積層方向上側の片面のみにあればよい。 Like the positive electrode active material layer 1B, the negative electrode active material layer 2B is also formed on one side or both sides of the negative electrode current collector layer 2A. Further, when the negative electrode layer 2 is formed in the lowermost layer of the positive electrode layer 1 and the negative electrode layer 2 in the stacking direction of the stacked body 4, the negative electrode active material layer 2B in the lowermost negative electrode layer 2 is stacked in the stacking direction It only needs to be on one side of the upper side.
　正極活物質層１Ｂ及び負極活物質層２Ｂは、電子を授受する正極活物質及び負極活物質を含む。この他、導電助剤や導イオン助剤、結着剤等を含んでもよい。正極活物質及び負極活物質は、リチウムイオンを効率的に挿入、脱離できることが好ましい。 The positive electrode active material layer 1B and the negative electrode active material layer 2B include a positive electrode active material and a negative electrode active material that exchange electrons. In addition to these, a conductive auxiliary agent, an ion conductive auxiliary agent, a binder and the like may be contained. The positive electrode active material and the negative electrode active material are preferably capable of efficiently inserting and releasing lithium ions.
（活物質材料）
　以降、正極活物質と負極活物質に用いることのできる活物質材料について説明する。本実施形態において、活物質材料は、ＬｉとＶとを含む、ポリリン酸化合物であるリン酸バナジウムリチウムが用いられる。なお、活物質材料は、リン酸バナジウムリチウムの単体であってもよいし、リン酸バナジウムリチウム以外の材料を含んでいてよい。リン酸バナジウムリチウム以外の材料としては、例えば、リン酸リチウムを用いることができる。活物質材料は、リン酸バナジウムリチウムを９０質量％以上含むことが好ましく、９５質量％以上含むことが特に好ましい。 (Active material)
Hereinafter, active material materials that can be used for the positive electrode active material and the negative electrode active material will be described. In this embodiment, lithium vanadium phosphate, which is a polyphosphoric acid compound, containing Li and V is used as the active material. The active material material may be a simple substance of lithium vanadium phosphate, or may include a material other than lithium vanadium phosphate. As a material other than lithium vanadium phosphate, lithium phosphate can be used, for example. The active material material preferably contains lithium vanadium phosphate in an amount of 90% by mass or more, and particularly preferably 95% by mass or more.
　リン酸バナジウムリチウムは、結晶軸におけるａ軸の長さＡ、ｂ軸の長さＢ、ｃ軸の長さＣが下記の式（１）～（３）の全てを満たす。
　１＜（Ａ／Ａ０）≦１．００３０　（１）
　１＜（Ｂ／Ｂ０）≦１．００５１　（２）
　１＜（Ｃ／Ｃ０）≦１．００４３　（３）
　式（１）～（３）において、Ａは、リン酸バナジウムリチウムの結晶軸におけるａ軸の長さを表し、Ａ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるａ軸の長さを表し、Ｂは、リン酸バナジウムリチウムの結晶軸におけるｂ軸の長さを表し、Ｂ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるｂ軸の長さを表し、Ｃは、リン酸バナジウムリチウムの結晶軸におけるｃ軸の長さを表し、Ｃ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるｃ軸の長さを表す。 In the lithium vanadium phosphate, the a-axis length A, the b-axis length B, and the c-axis length C of the crystal axes satisfy all of the following formulas (1) to (3).
1 <(A/A0) ≤ 1.0030 (1)
1<(B/B0)≦1.0051 (2)
1<(C/C0)≦1.043 (3)
In the formulas (1) to (3), A represents the length of the a-axis in the crystal axis of lithium vanadium phosphate, and A0 represents the a-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. B represents the length of the b-axis in the crystal axis of lithium vanadium phosphate, and B0 represents the length of the b-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. C represents the length of the c-axis in the crystal axis of lithium vanadium phosphate, and C0 represents the length of the c-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3 .
　式（１）～（３）において、無置換のＬｉ３Ｖ２（ＰＯ４）３は、ＬｉとＶとをモル比で３：２の割合で含む量論組成のリン酸バナジウムリチウム標準試料を意味する。リン酸バナジウムリチウム標準試料は、ＬｉＰＯ３とＶ２Ｏ３をモル比で３：１の割合で含む混合物を、還元性ガス雰囲気下、８５０℃の温度で２時間焼成して固相反応させることによって得られたものである。混合物は、ＬｉＰＯ３とＶ２Ｏ３を、硬質ボールとメタノールと共にボールミルに投入して、混合・粉砕した後、乾燥することによって得られたものである。還元性ガスとしては、例えば、３％の水素を含む水素－窒素混合ガスを用いることができる。 In the formulas (1) to (3), the unsubstituted Li 3 V 2 (PO 4 ) 3 is a stoichiometric lithium vanadium phosphate standard sample containing Li and V in a molar ratio of 3:2. means. The lithium vanadium phosphate standard sample is prepared by firing a mixture containing LiPO 3 and V 2 O 3 in a molar ratio of 3:1 at a temperature of 850° C. for 2 hours in a solid phase reaction. It was obtained by. The mixture was obtained by charging LiPO 3 and V 2 O 3 together with hard balls and methanol into a ball mill, mixing and pulverizing, and then drying. As the reducing gas, for example, a hydrogen-nitrogen mixed gas containing 3% hydrogen can be used.
　本実施形態のリン酸バナジウムリチウム及びリン酸バナジウムリチウム標準試料の結晶軸におけるａ軸の長さＡ及びＡ０、ｂ軸の長さＢ及びＢ０、ｃ軸の長さＣ及びＣ０（格子定数）は、Ｘ線回折パターンをリートベルト法によって解析することによって求めた値である。なお、格子定数は、リン酸バナジウムリチウムの空間群をＰ２１／Ｃとして求めた。 The a-axis lengths A and A0, the b-axis lengths B and B0, the c-axis lengths C and C0 (lattice constants) of the crystal axes of the lithium vanadium phosphate and lithium vanadium phosphate standard samples of the present embodiment are , X-ray diffraction pattern is analyzed by Rietveld method. The lattice constant was determined by setting the space group of lithium vanadium phosphate as P21/C.
　（Ａ／Ａ０）は、リン酸バナジウムリチウム標準試料の結晶軸におけるａ軸の長さＡ０に対するリン酸バナジウムリチウムの結晶軸におけるａ軸の長さＡの比である。（Ａ／Ａ０）が大きいほど、リン酸バナジウムリチウムの結晶格子がａ軸の方向に大きく拡げられたことを表す。（Ａ／Ａ０）は、１＜（Ａ／Ａ０）≦１．００３０を満足することが好ましく、１．００１２＜（Ａ／Ａ０）≦１．００３０を満足することが特に好ましい。 (A/A0) is the ratio of the length A of the a-axis in the crystal axis of lithium vanadium phosphate to the length A0 of the a-axis in the crystal axis of the lithium vanadium phosphate standard sample. The larger (A/A0) indicates that the crystal lattice of lithium vanadium phosphate was expanded in the a-axis direction. (A/A0) preferably satisfies 1<(A/A0)≦1.0030, and particularly preferably 1.0012<(A/A0)≦1.0030.
　（Ｂ／Ｂ０）は、リン酸バナジウムリチウム標準試料の結晶軸におけるｂ軸の長さＢ０に対するリン酸バナジウムリチウムの結晶軸におけるｂ軸の長さＢの比である。（Ｂ／Ｂ０）が大きいほど、リン酸バナジウムリチウムの結晶格子がｂ軸の方向に大きく拡げられたことを表す。（Ｂ／Ｂ０）は、１＜（Ｂ／Ｂ０）≦１．００５１を満足することが好ましく、１．００１１＜（Ｂ／Ｂ０）≦１．００５１を満足することが特に好ましい。 (B/B0) is the ratio of the b-axis length B of the lithium vanadium phosphate crystal axis to the b-axis length B0 of the lithium vanadium phosphate standard sample crystal axis. The larger (B/B0) indicates that the crystal lattice of lithium vanadium phosphate was expanded in the b-axis direction. (B/B0) preferably satisfies 1<(B/B0)≦1.0051, and particularly preferably 1.0011<(B/B0)≦1.051.
　（Ｃ／Ｃ０）は、リン酸バナジウムリチウム標準試料の結晶軸におけるｃ軸の長さＣ０に対するリン酸バナジウムリチウムの結晶軸におけるｃ軸の長さＣの比である。（Ｃ／Ｃ０）が大きいほど、リン酸バナジウムリチウムの結晶格子がｃ軸の方向に大きく拡げられたことを表す。（Ｃ／Ｃ０）は、１＜（Ｃ／Ｃ０）≦１．００４３を満足することが好ましく、１．００１０＜（Ｃ／Ｃ０）≦１．００４３を満足することが特に好ましい。 (C/C0) is the ratio of the length C of the c-axis in the crystal axis of lithium vanadium phosphate to the length C0 of the c-axis in the crystal axis of the lithium vanadium phosphate standard sample. The larger (C/C0) indicates that the crystal lattice of lithium vanadium phosphate was greatly expanded in the c-axis direction. (C/C0) preferably satisfies 1<(C/C0)≦1.043, and particularly preferably 1.0010<(C/C0)≦1.043.
　式（１）～（３）を満たすリン酸バナジウムリチウムを活物質として用いることによって、正極活物質層又は負極活物質層のリチウムイオン伝導度を向上させることができ、ひいては、リチウムイオン二次電池の放電容量を高くすることができる。 By using lithium vanadium phosphate satisfying the formulas (1) to (3) as an active material, the lithium ion conductivity of the positive electrode active material layer or the negative electrode active material layer can be improved, and by extension, the lithium ion secondary battery. The discharge capacity of can be increased.
　また、式（１）～（３）を満たすために、リン酸バナジウムリチウムにおけるバナジウム（Ｖ）の一部を別の元素で置換した活物質とすることが好ましい。置換する元素は、Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂのいずれかであることが好ましいが、特に限定されない。置換する元素は、一種であってもよいし、二種以上を組み合わせてもよい。 Further, in order to satisfy the formulas (1) to (3), it is preferable to use an active material in which a part of vanadium (V) in lithium vanadium phosphate is replaced with another element. The substituting element is preferably any of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb, but is not particularly limited. The substituting element may be one kind or a combination of two or more kinds.
　Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂは、イオン半径がＶと比して適度に大きいため、リン酸バナジウムリチウムのＶに対しての置換量を最適なものとすることができる。これにより式（１）～（３）を満たすことを容易とすることができ、ひいてはリチウムイオン二次電池の放電容量を高くすることができる。 Since Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb have an appropriately large ionic radius as compared with V, it is possible to optimize the substitution amount of lithium vanadium phosphate for V. it can. This makes it easy to satisfy the formulas (1) to (3), which in turn can increase the discharge capacity of the lithium ion secondary battery.
　更に、Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂの少なくともいずれか一つでＶの一部が置換されたリン酸バナジウムリチウムは、元素置換されていない活物質Ｌｉ３Ｖ２（ＰＯ４）３に比べて高い電子伝導性が得られ、ひいては、活物質の電子伝導性が向上し、全固体電池の内部抵抗を低減することが出来る。 Furthermore, lithium vanadium phosphate in which a part of V is substituted with at least one of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb is an active material Li 3 V 2 (with no element substitution). Higher electron conductivity than that of PO 4 ) 3 can be obtained, which in turn improves the electron conductivity of the active material and can reduce the internal resistance of the all-solid-state battery.
　また、リン酸バナジウムリチウムは、その主相が、下記の一般式（Ｉ）で表されることがより好ましい。なお、リン酸バナジウムリチウムの副相としては、例えばリン酸リチウムを挙げることができる。リン酸バナジウムリチウムは、主相を９０質量％以上含むことが好ましく、９５質量％以上含むことが特に好ましい。
　Ｌｉ３＋ａ（Ｖ２－ｘＭｘ）（ＰＯ４）３　（Ｉ）
　（一般式（Ｉ）において、Ｍは、Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂからなる群より選ばれる少なくとも一つの元素を表し、ｘは、０＜ｘ≦０．３を満たす数を表し、ａは、－３．０＜ａ＜３．０を満たす数を表す。） Further, it is more preferable that the main phase of lithium vanadium phosphate is represented by the following general formula (I). In addition, as a subphase of lithium vanadium phosphate, lithium phosphate can be mentioned, for example. Lithium vanadium phosphate preferably contains the main phase in an amount of 90% by mass or more, and particularly preferably 95% by mass or more.
Li 3+a (V 2-x M x )(PO 4 ) 3 (I)
(In the general formula (I), M represents at least one element selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb, and x is 0<x≦0.3. Represents the number satisfied, and a represents the number satisfying −3.0<a<3.0.)
　すなわち、リン酸バナジウムリチウムのＶの一部を、Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂのいずれかで置換する場合、式（Ｉ）に示すように、その置換量を０＜ｘ≦０．３とすることで、更に容易に式（１）～（３）に記載の結晶軸長を形成することができる。元素Ｍの置換量ｘが、０．３より大きくなると、元素置換が出来なくなる場合があり、置換元素の一部が異相として存在し始め、ひいてはイオン伝導度を低下させる場合がある。 That is, when a part of V of lithium vanadium phosphate is substituted with any of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb, the substitution amount is 0 as shown in formula (I). By setting <x≦0.3, the crystal axis lengths represented by the formulas (1) to (3) can be more easily formed. If the substitution amount x of the element M is larger than 0.3, element substitution may not be possible, a part of the substitution element may start to exist as a different phase, and eventually the ionic conductivity may be reduced.
　また、式（Ｉ）のように、リン酸バナジウムリチウムにおけるＬｉの量が、０モルを超えて、６．０モル未満であることがより好ましい。 Further, as in the formula (I), the amount of Li in lithium vanadium phosphate is more preferably more than 0 mol and less than 6.0 mol.
（導電助剤）
　導電助剤としては、例えば、カーボンブラック、アセチレンブラック、ケッチェンブラック、カーボンナノチューブ、グラファイト、グラフェン、活性炭等の炭素材料、金、銀、パラジウム、白金、銅、スズ等の金属材料が挙げられる。 (Conductive agent)
Examples of the conductive aid include carbon materials such as carbon black, acetylene black, Ketjen black, carbon nanotubes, graphite, graphene and activated carbon, and metal materials such as gold, silver, palladium, platinum, copper and tin.
（導イオン助剤）
　導イオン助剤としては、例えば、固体電解質である。固体電解質は、具体的に例えば、固体電解質３に用いられる材料と同様の材料を用いることができる。導イオン助剤として固体電解質を用いる場合、導イオン助剤と、固体電解質３に用いる固体電解質とが同じ材料を用いることが好ましい。 (Ion-conducting auxiliary agent)
The ion-conducting aid is, for example, a solid electrolyte. As the solid electrolyte, specifically, for example, the same material as the material used for the solid electrolyte 3 can be used. When a solid electrolyte is used as the ion-conducting auxiliary agent, it is preferable to use the same material as the ion-conducting auxiliary agent and the solid electrolyte used for the solid electrolyte 3.
＜固体電解質＞
　固体電解質３は、リン酸塩系固体電解質であることが好ましい。固体電解質３としては、電子の伝導性が小さく、リチウムイオンの伝導性が高い材料を用いることが好ましい。具体的には例えば、Ｌａ０．５Ｌｉ０．５ＴｉＯ３などのペロブスカイト型化合物や、Ｌｉ１４Ｚｎ（ＧｅＯ４）４などのリシコン型化合物、Ｌｉ７Ｌａ３Ｚｒ２Ｏ１２などのガーネット型化合物、Ｌｉ１．３Ａｌ０．３Ｔｉ１．７（ＰＯ４）３やＬｉ１．５Ａｌ０．５Ｇｅ１．５（ＰＯ４）３などのナシコン型化合物、Ｌｉ３．２５Ｇｅ０．２５Ｐ０．７５Ｓ４やＬｉ３ＰＳ４などのチオリシコン型化合物、Ｌｉ２Ｓ－Ｐ２Ｓ５やＬｉ２Ｏ－Ｖ２Ｏ５－ＳｉＯ２などのガラス化合物、Ｌｉ３ＰＯ４やＬｉ３．５Ｓｉ０．５Ｐ０．５Ｏ４やＬｉ２．９ＰＯ３．３Ｎ０．４６などのリン酸化合物、よりなる群から選択される少なくとも１種であることが望ましい。 <Solid electrolyte>
The solid electrolyte 3 is preferably a phosphate-based solid electrolyte. As the solid electrolyte 3, it is preferable to use a material having a low electron conductivity and a high lithium ion conductivity. Specifically, for example, perovskite type compounds such as La 0.5 Li 0.5 TiO 3 , lithicon type compounds such as Li 14 Zn(GeO 4 ) 4 and garnet type compounds such as Li 7 La 3 Zr 2 O 12 are used. , Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 and Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 Nasicon type compounds such as Li 3.25 Ge 0.25 Thiolysicon type compounds such as P 0.75 S 4 and Li 3 PS 4 , glass compounds such as Li 2 S—P 2 S 5 and Li 2 O—V 2 O 5 —SiO 2 , Li 3 PO 4 and Li 3. At least one selected from the group consisting of phosphoric acid compounds such as 5 Si 0.5 P 0.5 O 4 and Li 2.9 PO 3.3 N 0.46 is desirable.
　本実施形態において用いる固体電解質材料として、ナシコン型の結晶構造を有するリチウムイオン伝導体を用いることが好ましく、例えば、ＬｉＺｒ２（ＰＯ４）３、Ｌｉ１．３Ａｌ０．３Ｔｉ１．７（ＰＯ４）３、Ｌｉ１．５Ａｌ０．５Ｇｅ１．５（ＰＯ４）３で表される固体電解質材料を含むことが好ましい。ＬｉＺｒ２（ＰＯ４）３は、Ｚｒの一部をＣａまたはＹで置換してもよい。その例としては、Ｌｉ１．４Ｃａ０．２Ｚｒ１．８（ＰＯ４）３、Ｌｉ１．１５Ｙ０．１５Ｚｒ１．８５（ＰＯ４）３を挙げることができる。 As the solid electrolyte material used in the present embodiment, it is preferable to use a lithium ion conductor having a Nasicon type crystal structure, for example, LiZr 2 (PO 4 ) 3 , Li 1.3 Al 0.3 Ti 1.7 ( It is preferable to include a solid electrolyte material represented by PO 4 ) 3 and Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 . LiZr 2 (PO 4 ) 3 may substitute a part of Zr with Ca or Y. Examples thereof include Li 1.4 Ca 0.2 Zr 1.8 (PO 4 ) 3 and Li 1.15 Y 0.15 Zr 1.85 (PO 4 ) 3 .
＜端子電極＞
　端子電極５，６は、図１に示すように、積層体４の側面（正極層１及び負極層２の端面の露出面）に接して形成されている。端子電極５，６は外部端子に接続されて、積層体４への電子の授受を担う。 <Terminal electrode>
As shown in FIG. 1, the terminal electrodes 5 and 6 are formed in contact with the side surfaces (exposed surfaces of the end surfaces of the positive electrode layer 1 and the negative electrode layer 2) of the laminated body 4. The terminal electrodes 5 and 6 are connected to external terminals and serve to transfer electrons to and from the stacked body 4.
　端子電極５，６には、導電率が大きい材料を用いることが好ましい。例えば、銀、金、プラチナ、アルミニウム、銅、スズ、ニッケル、ガリウム、インジウム、及びこれらの合金などを用いることができる。 It is preferable to use a material having high conductivity for the terminal electrodes 5 and 6. For example, silver, gold, platinum, aluminum, copper, tin, nickel, gallium, indium, and alloys thereof can be used.
（セラミックス材料の製造方法）
　本実施形態の全固体電池１０で用いられるセラミックス材料の製造方法について説明する。全固体電池１０の活物質材料として用いられる本実施形態のリン酸バナジウムリチウムは、Ｌｉ化合物と、Ｖ化合物と、リン酸化合物またはリン酸Ｌｉ化合物とイットリウム化合物、ガドリニウム化合物、テルビウム化合物、ジスプロシウム化合物、ホルミウム化合物、エルビウム化合物、ツリウム化合物、イッテルビウム化合物を混合した混合原料を熱処理することにより得ることができる。また、全固体電池１０の固体電解質材料として用いられるリン酸チタンアルミニウムリチウム材料は、Ｌｉ化合物と、Ａｌ化合物、Ｔｉ化合物、リン酸化合物、またはリン酸Ｔｉ化合物とを混合した混合原料を熱処理することにより得ることができる。 (Method of manufacturing ceramics material)
A method of manufacturing the ceramic material used in the all-solid-state battery 10 of this embodiment will be described. Lithium vanadium phosphate of this embodiment used as an active material of the all-solid-state battery 10 is a Li compound, a V compound, a phosphoric acid compound or a phosphoric acid Li compound and an yttrium compound, a gadolinium compound, a terbium compound, a dysprosium compound, It can be obtained by heat-treating a mixed raw material in which a holmium compound, an erbium compound, a thulium compound, and a ytterbium compound are mixed. The lithium aluminum titanium phosphate material used as the solid electrolyte material of the all-solid-state battery 10 is obtained by heat-treating a mixed raw material in which a Li compound is mixed with an Al compound, a Ti compound, a phosphoric acid compound, or a Ti phosphate compound. Can be obtained by
　Ｌｉ化合物としては、例えば、ＬｉＯＨ又はその水和物、Ｌｉ２ＣＯ３、ＬｉＮＯ３、ＣＨ３ＣＯＯＬｉ等を挙げることができる。Ｖ化合物としては、Ｖ２Ｏ３、Ｖ２Ｏ５等を挙げることができる。リン化合物としては、Ｈ３ＰＯ４、ＮＨ４Ｈ２ＰＯ４、（ＮＨ４）２ＨＰＯ４等を挙げることができる。また、リン酸Ｌｉ化合物としては、ＬｉＰＯ３、Ｌｉ４Ｐ２Ｏ７、Ｌｉ５Ｐ３Ｏ１０、Ｌｉ６Ｐ４Ｏ１４等を挙げることができる。さらにイットリウム化合物、ガドリニウム化合物、テルビウム化合物、ジスプロシウム化合物、ホルミウム化合物、エルビウム化合物、ツリウム化合物、イッテルビウム化合物としては、Ｙ２Ｏ３、Ｇｄ２Ｏ３、Ｔｂ２Ｏ３、Ｄｙ２Ｏ３、Ｈｏ２Ｏ３、Ｅｒ２Ｏ３、Ｔｍ２Ｏ３、Ｙｂ２Ｏ３等を挙げることができる。 Examples of the Li compound include LiOH or a hydrate thereof, Li 2 CO 3 , LiNO 3 , CH 3 COOLi, and the like. Examples of the V compound include V 2 O 3 and V 2 O 5 . Examples of the phosphorus compound include H 3 PO 4 , NH 4 H 2 PO 4 , (NH 4 ) 2 HPO 4, and the like. As the phosphoric acid Li compound, mention may be made of LiPO 3, Li 4 P 2 O 7, Li 5 P 3 O 10, Li 6 P 4 O 14 and the like. Further, yttrium compounds, gadolinium compounds, terbium compounds, dysprosium compounds, holmium compounds, erbium compounds, thulium compounds, and ytterbium compounds include Y 2 O 3 , Gd 2 O 3 , Tb 2 O 3 , Dy 2 O 3 , and Ho 2 O. 3, Er 2 O 3, Tm 2 O 3, Yb 2 O 3 and the like.
　また、Ａｌ化合物としては、Ａｌ２Ｏ３、Ａｌ（ＯＨ）３、Ａｌ２（ＳＯ４）３等を挙げることができる。Ｔｉ化合物としては、ＴｉＯ２、Ｔｉ２Ｏ３、ＴｉＣｌ４、Ｔｉ（ＯＲ）４等を挙げることができる。リン酸Ｔｉ化合物としては、ＴｉＰ２Ｏ７、Ｔｉ３Ｐ４Ｏ１６等を挙げることができる。 Examples of Al compounds include Al 2 O 3 , Al(OH) 3 , and Al 2 (SO 4 ) 3 . Examples of the Ti compound include TiO 2 , Ti 2 O 3 , TiCl 4 , and Ti(OR) 4 . Examples of the Ti phosphate compound include TiP 2 O 7 and Ti 3 P 4 O 16 .
　本実施形態にかかるリン酸バナジウムリチウムの製造方法の一例について説明する。このリン酸バナジウムリチウムの製造方法は、（ａ）原料混合工程を行い、次に（ｂ）仮焼工程を行い、最後に（ｃ）粉砕工程を行う。以下に、これらの工程について順に説明する。 An example of a method for producing lithium vanadium phosphate according to this embodiment will be described. In this method for producing lithium vanadium phosphate, (a) raw material mixing step is performed, then (b) calcination step is performed, and finally (c) crushing step is performed. Below, these processes are demonstrated in order.
（ａ）原料混合工程
　原料混合工程では、リン酸バナジウムリチウムにおいて、所望の組成になるように出発原料をそれぞれ秤量し、混合する。出発原料としては、各元素の炭酸塩や硫酸塩、硝酸塩、シュウ酸塩、塩化物、水酸化物、酸化物、リン酸塩などを用いることができる。このうち、すでにリン酸リチウムとして得られている原料や酸化物が熱処理に対して不要なガスの発生が無く好ましいが、さらに炭酸ガスを生じる炭酸塩や熱分解して水蒸気を生じる水酸化物が好ましい。混合方法は、溶媒に入れずに乾式で混合粉砕してもよいし、溶媒に入れて湿式で混合粉砕してもよいが、溶媒に入れて湿式の混合粉砕を行うことが混合性の向上の面からは好ましい。この混合方法は、例えば、遊星ミル、アトライター、ボールミルなどを用いることができる。溶媒としては、Ｌｉが溶解しにくいものが好ましく、例えばエタノールなどの有機溶媒がより好ましい。混合時間は、混合量にもよるが、例えば１時間～３２時間とすることができる。また、リン酸チタンアルミニウムリチウムにおいても、所望の組成になるように出発原料をそれぞれ秤量し、いずれかの方法で混合する。 (A) Raw Material Mixing Step In the raw material mixing step, starting materials of lithium vanadium phosphate are weighed and mixed so as to have a desired composition. As the starting material, carbonates, sulfates, nitrates, oxalates, chlorides, hydroxides, oxides, phosphates of each element can be used. Of these, the raw materials and oxides already obtained as lithium phosphate are preferable because there is no generation of unnecessary gas for heat treatment, and further, carbonates that generate carbon dioxide and hydroxides that thermally decompose to generate water vapor are preferable. preferable. The mixing method may be dry-mixing and pulverizing without putting in a solvent, or wet mixing and pulverizing in a solvent. However, performing wet mixing and pulverizing in a solvent may improve the mixing property. From the aspect, it is preferable. As the mixing method, for example, a planetary mill, an attritor, a ball mill or the like can be used. As the solvent, a solvent in which Li is difficult to dissolve is preferable, and an organic solvent such as ethanol is more preferable. The mixing time may be, for example, 1 hour to 32 hours, depending on the mixing amount. Further, in the case of lithium aluminum aluminum phosphate, the starting materials are weighed so as to have a desired composition and mixed by any method.
（ｂ）仮焼工程
　仮焼工程では、原料混合工程で得られた混合粉末を仮焼する。このときの仮焼温度は、出発原料の状態変化（例えば相変化など）が起きる温度以上が好ましい。例えば、出発原料の一つとしてＬｉ２ＣＯ３を用いた場合には、この炭酸塩が分解し所望のリン酸バナジウムリチウム相が生成する温度以上が好ましい。具体的には、仮焼温度は、６００℃～１０００℃とすることが好ましい。また、リン酸バナジウムリチウム中の３価のＶ量を制御するために、仮焼時の雰囲気は不活性ガス雰囲気ないしは還元ガス雰囲気が好ましい。不活性ガスとしては、例えば、窒素ガス、アルゴンガスを用いることができる。還元ガスとしては、例えば、水素ガスと不活性ガスとを含む混合ガスを用いることができる。混合ガスの水素濃度は、０．１体積％以上５体積％以下の範囲内にあることが好ましい。リン酸バナジウムリチウム中のＶ中の３価のＶ量を制御するために、混合ガスの水素ガス濃度を変化させてもよい。例えば、混合ガスの水素濃度を、焼成開始時は５体積％と高くして、焼成終了時は０．１体積％と低くしてもよい。また、リン酸チタンアルミニウムリチウムにおいても混合工程で得られた混合粉末を仮焼する。具体的には、仮焼温度は、８００℃～１０００℃とすることが好ましい。また、仮焼時の雰囲気は、チタンが還元を受けない雰囲気が好ましく、具体的は大気雰囲気が好ましい。 (B) Calcining Step In the calcining step, the mixed powder obtained in the raw material mixing step is calcined. The calcination temperature at this time is preferably a temperature at which the state change (for example, phase change) of the starting material occurs or higher. For example, when Li 2 CO 3 is used as one of the starting materials, the temperature is preferably higher than the temperature at which this carbonate is decomposed and a desired lithium vanadium phosphate phase is formed. Specifically, the calcination temperature is preferably 600°C to 1000°C. Further, in order to control the amount of trivalent V in lithium vanadium phosphate, the atmosphere during calcination is preferably an inert gas atmosphere or a reducing gas atmosphere. As the inert gas, for example, nitrogen gas or argon gas can be used. As the reducing gas, for example, a mixed gas containing hydrogen gas and an inert gas can be used. The hydrogen concentration of the mixed gas is preferably in the range of 0.1% by volume or more and 5% by volume or less. The hydrogen gas concentration of the mixed gas may be changed in order to control the amount of trivalent V in V in lithium vanadium phosphate. For example, the hydrogen concentration of the mixed gas may be as high as 5% by volume at the start of firing and as low as 0.1% by volume at the end of firing. Further, with lithium aluminum lithium phosphate, the mixed powder obtained in the mixing step is also calcined. Specifically, the calcination temperature is preferably 800°C to 1000°C. Further, the atmosphere during the calcination is preferably an atmosphere in which titanium is not reduced, and specifically, an air atmosphere is preferable.
（ｃ）粉砕工程
　粉砕では、仮焼工程で反応凝集した材料を適切な粒子径と分布を有する粉体にする工程になる。粉砕方法は、溶媒に入れずに乾式で粉砕してもよいし、溶媒に入れて湿式で粉砕してもよい。この粉砕方法は、例えば、遊星ミル、アトライター、ボールミルなどを用いることができる。溶媒としては、リン酸バナジウムリチウムがより安定に粉砕できるために、例えばエタノールなどの有機溶媒がより好ましい。粉砕時間は、粉砕量にもよるが、例えば０．５時間～３２時間とすることができる。 (C) Pulverizing Step In the pulverizing step, the material reactively aggregated in the calcination step is converted into a powder having an appropriate particle size and distribution. The pulverization method may be dry pulverization without adding it to a solvent, or wet pulverization with addition to a solvent. As the grinding method, for example, a planetary mill, an attritor, a ball mill or the like can be used. As the solvent, an organic solvent such as ethanol is more preferable because lithium vanadium phosphate can be ground more stably. The crushing time may be, for example, 0.5 hour to 32 hours, depending on the crushing amount.
　以上詳述した製法によれば、出発原料の混合粉末を比較的低温で仮焼を行うため、組成のずれを精度よく抑制することができる。なお、本実施形態においてリン酸バナジウムリチウムの製法は、これに限定されるものではなく、他の製法を採用しても構わない。 According to the manufacturing method described in detail above, since the mixed powder of the starting materials is calcined at a relatively low temperature, it is possible to accurately suppress the composition deviation. In addition, in this embodiment, the manufacturing method of lithium vanadium phosphate is not limited to this, and other manufacturing methods may be adopted.
（リン酸バナジウムリチウムのイオン伝導度の評価方法）
　本実施形態に係るリン酸バナジウムリチウムは、高いイオン伝導度を有する。次に、リン酸バナジウムリチウムのイオン伝導度の評価方法について説明する。リン酸バナジウムリチウムのイオン伝導度の評価方法は、例えば、（ｄ）成形工程と、（ｅ）脱バインダー及び焼成工程と、（ｆ）イオン伝導率評価工程を含む。 (Method for evaluating ionic conductivity of lithium vanadium phosphate)
The lithium vanadium phosphate according to this embodiment has high ionic conductivity. Next, a method for evaluating the ionic conductivity of lithium vanadium phosphate will be described. The method for evaluating the ionic conductivity of lithium vanadium phosphate includes, for example, (d) a molding step, (e) a binder removal and firing step, and (f) an ionic conductivity evaluation step.
（ｄ）成形工程
　成形工程では、仮焼工程で得られた材料（本焼結前粉末という）を成形した後、仮焼温度以上の温度で焼結を行う。成形体を得るための成形方法としては、本焼結前粉末にバインダーを添加し金型成形を行う方法、冷間等方成形（ＣＩＰ）や熱間等方成形（ＨＩＰ）、ホットプレスなどにより任意の形状に行うことができる。さらに、焼結前粉末を有機系のバインダー、分散剤、可塑剤等と混合し、シート状に成形し、複数積層構造に成形しても良い。 (D) Forming Step In the forming step, after the material obtained in the calcination step (referred to as pre-sintering powder) is formed, sintering is performed at a temperature higher than the calcination temperature. As a molding method for obtaining a molded body, a method of adding a binder to the pre-sintering powder to perform mold molding, cold isotropic molding (CIP), hot isotropic molding (HIP), hot pressing, etc. It can be performed in any shape. Furthermore, the powder before sintering may be mixed with an organic binder, a dispersant, a plasticizer, etc., and molded into a sheet to form a multilayer structure.
（ｅ）脱バインダー及び焼成工程
　バインダーを用いた場合の脱バインダーは窒素中もしくは還元ガス雰囲気下で１０℃／時間から５００℃／時間の昇温速度を用い、脱バインダー温度は５００℃から９００℃で、その温度に１時間から１０時間保持する。また焼成は、窒素中または還元ガス雰囲気下で昇温速度５０℃／時間から３６００℃／時間を用い、焼成温度７００℃から１２００℃まで昇温して、その温度に１０分から５時間保持し冷却する。 (E) Debinding and firing process When using a binder, the debinding is performed in nitrogen or in a reducing gas atmosphere at a heating rate of 10°C/hour to 500°C/hour, and the debinding temperature is 500°C to 900°C. Then, the temperature is maintained for 1 to 10 hours. The firing is performed in nitrogen or in a reducing gas atmosphere at a heating rate of 50° C./hour to 3600° C./hour, the firing temperature is raised from 700° C. to 1200° C., and the temperature is kept for 10 minutes to 5 hours to cool. To do.
（ｆ）伝導率評価工程
　焼成工程で得られた板状の焼成体の両面に対して電極を形成する。電極はＣｕ、Ａｇ、Ａｕ、Ｐｄ等で良く、形成方法としては、ペースト焼き付け法、蒸着法、スパッタ法を用いてよい。電極を形成した資料は、恒温槽中にてＡＣインピーダンスアナライザーを用い、測定温度を一定にした状態で周波数に対するインピーダンスと位相角を測定する。これらの測定値をもとにナイキストプロットを描きその円弧より抵抗値を求め、この抵抗値から導電率を算出する。 (F) Conductivity evaluation step Electrodes are formed on both sides of the plate-shaped fired body obtained in the firing step. The electrodes may be Cu, Ag, Au, Pd or the like, and as a forming method, a paste baking method, a vapor deposition method or a sputtering method may be used. The material on which the electrodes are formed is measured in impedance and phase angle with respect to frequency with the measurement temperature kept constant using an AC impedance analyzer in a constant temperature bath. Based on these measured values, a Nyquist plot is drawn, the resistance value is obtained from the arc, and the conductivity is calculated from this resistance value.
（全固体電池の製造方法）
　本実施形態の全固体電池は、正極集電体層、正極活物質層、固体電解質層、負極活物質層、及び、負極集電体層の各材料をペースト化し、塗布乾燥してグリーンシートを作製し、係るグリーンシートを積層し、作製した積層体を同時に焼成することにより製造する。 (Method of manufacturing all-solid-state battery)
The all-solid-state battery of the present embodiment, the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and each material of the negative electrode current collector layer is made into a paste, coated and dried to form a green sheet. It is manufactured by stacking the manufactured green sheets and firing the manufactured stack at the same time.
　ペースト化の方法は、特に限定されないが、例えば、ビヒクルに上記各材料の粉末を混合してペーストを得ることができる。ここで、ビヒクルとは、液相における媒質の総称である。ビヒクルには、溶媒、バインダーが含まれる。係る方法により、正極集電体層用のペースト、正極活物質層用のペースト、固体電解質層用のペースト、負極活物質層用のペースト、及び、負極集電体層用のペーストを作製する。 The method of forming a paste is not particularly limited, but for example, a paste can be obtained by mixing a vehicle with powders of the above materials. Here, the vehicle is a general term for a medium in a liquid phase. The vehicle includes a solvent and a binder. By such a method, a paste for a positive electrode current collector layer, a paste for a positive electrode active material layer, a paste for a solid electrolyte layer, a paste for a negative electrode active material layer, and a paste for a negative electrode current collector layer are produced.
　作製したペーストをＰＥＴなどの基材上に所望の順序で塗布し、必要に応じ乾燥させた後、基材を剥離し、グリーンシートを作製する。ペーストの塗布方法は、特に限定されず、スクリーン印刷、塗布、転写、ドクターブレード等の公知の方法を採用することができる。 Apply the prepared paste on a base material such as PET in a desired order, dry it if necessary, and then peel the base material to prepare a green sheet. The method of applying the paste is not particularly limited, and known methods such as screen printing, application, transfer, doctor blade, etc. can be adopted.
　作製したグリーンシートを所望の順序、積層数で積み重ね、必要に応じアライメント、切断等を行い、積層ブロックを作製する。並列型又は直並列型の電池を作製する場合は、正極層の端面と負極層の端面が一致しないようにアライメントを行い積み重ねるのが好ましい。 Laminate the produced green sheets in the desired order and the number of layers, and perform alignment, cutting, etc. as necessary to produce a laminated block. When a parallel type or a serial parallel type battery is manufactured, it is preferable to perform alignment and stack so that the end surface of the positive electrode layer and the end surface of the negative electrode layer do not coincide with each other.
　積層ブロックを作製するに際し、以下に説明する活物質ユニットを準備し、積層ブロックを作製してもよい。 When manufacturing the laminated block, the active material unit described below may be prepared and the laminated block may be manufactured.
　その方法は、まずＰＥＴフィルム上に固体電解質層用ペーストをドクターブレード法でシート状に形成し、固体電解質シートを得た後、その固体電解質シート上に、スクリーン印刷により正極活物質層用ペーストを印刷し乾燥する。次に、その上に、スクリーン印刷により正極集電体層用ペーストを印刷し乾燥する。更にその上に、スクリーン印刷により正極活物質層用ペーストを再度印刷し、乾燥し、次いでＰＥＴフィルムを剥離することで正極活物質層ユニットを得る。このようにして、固体電解質シート上に、正極活物質層用ペースト、正極集電体層用ペースト、正極活物質層用ペーストがこの順に形成された正極活物質層ユニットを得る。同様の手順にて負極活物質層ユニットも作製し、固体電解質シート上に、負極活物質層用ペースト、負極集電体層用ペースト、負極活物質層用ペーストがこの順に形成された負極活物質層ユニットを得る。 The method is to first form a solid electrolyte layer paste on a PET film into a sheet by a doctor blade method, obtain a solid electrolyte sheet, and then paste the positive electrode active material layer paste by screen printing on the solid electrolyte sheet. Print and dry. Then, a positive electrode current collector layer paste is printed thereon by screen printing and dried. Further, a positive electrode active material layer paste is printed again by screen printing, dried, and then the PET film is peeled off to obtain a positive electrode active material layer unit. In this way, a positive electrode active material layer unit is obtained in which the positive electrode active material layer paste, the positive electrode current collector layer paste, and the positive electrode active material layer paste are formed in this order on the solid electrolyte sheet. A negative electrode active material layer unit was also produced by the same procedure, and a negative electrode active material layer paste, a negative electrode current collector layer paste, and a negative electrode active material layer paste were formed in this order on a solid electrolyte sheet. Get a layer unit.
　正極活物質層ユニット一枚と負極活物質層ユニット一枚を、固体電解質シートを介するようにして積み重ねる。このとき、一枚目の正極活物質層ユニットの正極集電体層用ペーストが一の端面にのみ延出し、二枚目の負極活物質層ユニットの負極集電体層用ペーストが他の面にのみ延出するように、各ユニットをずらして積み重ねる。この積み重ねられたユニットの両面に所定厚みの固体電解質シートをさらに積み重ね積層ブロックを作製する。 Lay one positive electrode active material layer unit and one negative electrode active material layer unit with a solid electrolyte sheet in between. At this time, the positive electrode current collector layer paste of the first positive electrode active material layer unit extends only to one end surface, and the negative electrode current collector layer paste of the second negative electrode active material layer unit is applied to the other surface. Stagger each unit so that it only extends to. Solid electrolyte sheets having a predetermined thickness are further stacked on both sides of the stacked units to form a laminated block.
　作製した積層ブロックを一括して圧着する。圧着は加熱しながら行うが、加熱温度は、例えば、４０～９５℃とする。 ❖ Press the manufactured laminated blocks together. The pressure bonding is performed while heating, and the heating temperature is, for example, 40 to 95°C.
　圧着した積層ブロックを、例えば、窒素ガス雰囲気下で６００℃～１１００℃に加熱し焼成を行う。焼成時間は、例えば、０．１～３時間とする。この焼成により積層体が完成する。 The pressure-bonded laminated block is heated to, for example, 600°C to 1100°C in a nitrogen gas atmosphere and fired. The firing time is, for example, 0.1 to 3 hours. This firing completes the laminated body.
［第２実施形態］
　第２実施形態は、固体電解質を用いないリチウム二次電池に係る。なお、本実施形態における活物質については、第１実施形態と同様の活物質を用いるため、重複した記述についてはその旨を記したうえで割愛する。 [Second Embodiment]
The second embodiment relates to a lithium secondary battery that does not use a solid electrolyte. Since the same active material as in the first embodiment is used as the active material in the present embodiment, duplicate description will be omitted after describing it.
　図２に示すように、本実施形態に係るリチウムイオン二次電池１００は、互いに対向する板状の負極２１及び板状の正極１１と、負極２１と正極１１との間に隣接して配置される板状のセパレータ１８と、を備える発電要素３０と、リチウムイオンを含む電解質溶液と、これらを密閉した状態で収容するケース５０と、負極２１に一方の端部が電気的に接続されると共に他方の端部がケースの外部に突出される負極リード６２と、正極１１に一方の端部が電気的に接続されると共に他方の端部がケースの外部に突出される正極リード６０とを備える。 As shown in FIG. 2, the lithium-ion secondary battery 100 according to the present embodiment is arranged adjacent to each other between the plate-shaped negative electrode 21 and the plate-shaped positive electrode 11, which face each other, and the negative electrode 21 and the positive electrode 11. A power generation element 30 including a plate-shaped separator 18 that has a plate-like separator, an electrolyte solution containing lithium ions, a case 50 that houses these in a sealed state, and one end of the negative electrode 21 is electrically connected and The negative electrode lead 62 has the other end protruding outside the case, and the positive electrode lead 60 has one end electrically connected to the positive electrode 11 and the other end protruding outside the case. ..
　負極２１は、負極集電体２２と、負極集電体２２上に形成された負極活物質層２４と、を有する。また、正極１１は、正極集電体１２と、正極集電体１２上に形成された正極活物質層１４と、を有する。セパレータ１８は、負極活物質層２４と正極活物質層１４との間に位置している。 The negative electrode 21 has a negative electrode current collector 22 and a negative electrode active material layer 24 formed on the negative electrode current collector 22. Further, the positive electrode 11 has a positive electrode current collector 12 and a positive electrode active material layer 14 formed on the positive electrode current collector 12. The separator 18 is located between the negative electrode active material layer 24 and the positive electrode active material layer 14.
　正極活物質層１４と負極活物質層２４は、活物質と導電助剤とバインダーとを含む。 The positive electrode active material layer 14 and the negative electrode active material layer 24 include an active material, a conductive additive, and a binder.
　活物質は、第１実施形態に記載したリン酸バナジウムリチウムを用いることができる。このリン酸バナジウムリチウムは、正極活物質層と負極活物質層のどちらか一方に用いてもよいし、両方に用いてもよい。 The lithium vanadium phosphate described in the first embodiment can be used as the active material. This lithium vanadium phosphate may be used in either one of the positive electrode active material layer and the negative electrode active material layer, or may be used in both.
　このように、固体電解質を用いないリチウム二次電池においても、第１実施形態と同様の活物質を用いることで、高い放電容量を得ることが可能である。 In this way, even in a lithium secondary battery that does not use a solid electrolyte, it is possible to obtain a high discharge capacity by using the same active material as in the first embodiment.
　次に実施例及び比較例を参照してより具体的に説明するが、本発明は以下の実施例に限定されるものではない。 Next, more detailed description will be given with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
［実施例１］
（活物質材料の作製）
　本実施形態の効果を実証するために、リン酸バナジウムリチウムにおいてＬｉ３Ｖ１．９７Ｙｂ０．０３（ＰＯ４）３になるように原料の秤量を行った。出発原料にはＬｉＰＯ３、Ｖ２Ｏ３、Ｙｂ２Ｏ３を用いた。はじめに、出発原料を秤量後、エタノール中にてボールミル（１２０ｒｐｍ／ジルコニアボール）で１６時間、混合・粉砕を行った。出発原料の混合粉末をボールとエタノールから分離し乾燥した後、マグネシア製坩堝を用いて仮焼を行った。仮焼はリン酸バナジウムリチウム中の３価のＶ量を制御するために、還元ガス雰囲気下で、９５０℃、２時間で行った。還元ガスは窒素ガスと水素ガスの混合ガスを用い、仮焼開始は水素ガス濃度を５体積％とし、０．１体積％まで連続的に変化させた。その後、仮焼粉末を、粉砕のためエタノール中にてボールミル（１２０ｒｐｍ／ジルコニアボール）で１６時間処理を行った。粉砕粉末をボールとエタノールから分離し乾燥して、バナジウム位にイッテルビウムが置換されたリン酸バナジウムリチウム粉末を得た。 [Example 1]
(Preparation of active material)
In order to demonstrate the effect of this embodiment, the raw materials were weighed so that lithium vanadium phosphate had Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 . LiPO 3 , V 2 O 3 , and Yb 2 O 3 were used as starting materials. First, after weighing the starting materials, they were mixed and pulverized in ethanol with a ball mill (120 rpm/zirconia balls) for 16 hours. The mixed powder of the starting materials was separated from the balls and ethanol, dried, and then calcined using a magnesia crucible. The calcination was performed in a reducing gas atmosphere at 950° C. for 2 hours in order to control the amount of trivalent V in lithium vanadium phosphate. As the reducing gas, a mixed gas of nitrogen gas and hydrogen gas was used, and the calcination was started at a hydrogen gas concentration of 5% by volume and continuously changed to 0.1% by volume. Then, the calcined powder was treated with a ball mill (120 rpm/zirconia ball) for 16 hours in ethanol for pulverization. The ground powder was separated from the balls and ethanol and dried to obtain lithium vanadium phosphate powder in which ytterbium was substituted at the vanadium position.
（組成と格子定数の測定）
　イッテルビウム置換リン酸バナジウムリチウムの組成はＩＣＰ発光分光分析法を用いて確認した。また、イッテルビウム置換リン酸バナジウムリチウムの格子定数（ａ軸の長さＡ、ｂ軸の長さＢ及びｃ軸の長さＣ）はＸ線回折法によって測定したＸ線回折パターンより得られた２θと強度データからリートベルト法を用いて算出した。なお、Ｘ線回折パターンの測定条件は下記のとおりである。 (Measurement of composition and lattice constant)
The composition of the ytterbium-substituted lithium vanadium phosphate was confirmed using ICP emission spectroscopy. Further, the lattice constants of the ytterbium-substituted lithium vanadium phosphate (a-axis length A, b-axis length B and c-axis length C) were 2θ obtained from an X-ray diffraction pattern measured by an X-ray diffraction method. And calculated from the strength data using the Rietveld method. The measurement conditions of the X-ray diffraction pattern are as follows.
（Ｘ線回折パターンの測定条件）
　ＰＡＮａｌｙｔｉｃａｌ社製Ｘ‘Ｐｅｒｔ　ＭＰＤ装置を使用し、Ｘ線源としてＣｕのＫα線を用い、２θ＝５～６５°間を０．０７°／秒の速度でスキャンして、Ｘ線回折パターンを測定した。 (Measurement condition of X-ray diffraction pattern)
Using an X'Pert MPD apparatus manufactured by PANalytical, using Kα rays of Cu as an X-ray source, scanning at a rate of 0.07°/sec between 2θ=5 and 65°, and measuring an X-ray diffraction pattern. did.
（リン酸バナジウムリチウム標準試料の作製、及び組成と格子定数の測定）
　出発原料として、ＬｉＰＯ３とＶ２Ｏ３を用いた。ＬｉＰＯ３とＶ２Ｏ３をモル比で３：１の割合で秤量した。秤量したＬｉＰＯ３とＶ２Ｏ３を、硬質ボール（ジルコニアボール）とメタノールと共にボールミルに投入して、混合・粉砕した。その後、混合物をメタノールから分離し、乾燥した。乾燥後の混合物を、３％の水素を含む水素－窒素混合ガス雰囲気下で８５０℃の温度で、２時間焼成した。その後、焼成粉末を、粉砕のためエタノール中にてボールミル（１２０ｒｐｍ／ジルコニアボール）で１６時間処理を行った。粉砕粉末をボールとエタノールから分離し乾燥して、リン酸バナジウムリチウム標準試料を得た。リン酸バナジウムリチウム標準試料の組成をＩＣＰ発光分光分析法を用いて確認したところ、ＬｉとＶとをモル比で３：２の割合で含む無置換のリン酸バナジウムリチウムであることが確認された。同様にリン酸バナジウムリチウム標準試料に対してもＸ線回折法により２θと強度データを測定し、リートベルト法を用いて格子定数（ａ軸の長さＡ０、ｂ軸の長さＢ０及びｃ軸の長さＣ０）を算出した。その結果、ａ軸の長さＡ０は、８．６０８５Å、ｂ軸の長さＢ０は、８．５９４１Å、ｃ－軸の長さＣ０は、１４．７２６７Åであった。 (Preparation of lithium vanadium phosphate standard sample and measurement of composition and lattice constant)
LiPO 3 and V 2 O 3 were used as starting materials. LiPO 3 and V 2 O 3 were weighed in a molar ratio of 3:1. The weighed LiPO 3 and V 2 O 3 were put into a ball mill together with hard balls (zirconia balls) and methanol, and mixed and pulverized. Then the mixture was separated from methanol and dried. The dried mixture was baked at a temperature of 850° C. for 2 hours under a hydrogen-nitrogen mixed gas atmosphere containing 3% hydrogen. Then, the fired powder was treated with a ball mill (120 rpm/zirconia ball) in ethanol for 16 hours for pulverization. The ground powder was separated from the balls and ethanol and dried to obtain a lithium vanadium phosphate standard sample. When the composition of the lithium vanadium phosphate standard sample was confirmed by ICP emission spectroscopy, it was confirmed to be an unsubstituted lithium vanadium phosphate containing Li and V in a molar ratio of 3:2. .. Similarly, for a lithium vanadium phosphate standard sample, 2θ and intensity data were measured by the X-ray diffraction method, and the Rietveld method was used to measure the lattice constants (a-axis length A0, b-axis length B0 and c-axis). The length C0) was calculated. As a result, the a-axis length A0 was 8.6085Å, the b-axis length B0 was 8.5941Å, and the c-axis length C0 was 14.72667Å.
　得られたイッテルビウム置換リン酸バナジウムリチウムの格子定数（ａ軸の長さＡ、ｂ軸の長さＢ及びｃ軸の長さＣ）と、リン酸バナジウムリチウム標準試料の格子定数（ａ軸の長さＡ０、ｂ軸の長さＢ０及びｃ軸の長さＣ０）とを用いて、（Ａ／Ａ０）、（Ｂ／Ｂ０）、（Ｃ／Ｃ０）を算出した。（Ａ／Ａ０）をａ軸倍率とし、（Ｂ／Ｂ０）をｂ軸倍率とし、（Ｃ／Ｃ０）をｃ軸倍率として、表１に示す。 The lattice constants (a-axis length A, b-axis length B and c-axis length C) of the obtained ytterbium-substituted lithium vanadium phosphate, and the lattice constants of the lithium vanadium phosphate standard sample (a-axis length) (A/A0), (B/B0), and (C/C0) were calculated using the length A0, the b-axis length B0, and the c-axis length C0). Table 1 shows (A/A0) as the a-axis magnification, (B/B0) as the b-axis magnification, and (C/C0) as the c-axis magnification.
（伝導度の評価）
　さらに実施例１で作製したイッテルビウム置換リン酸バナジウムリチウム粉末を３．５Ｍｐａの圧力下で直径１０ｍｍの円形型ペレットを加圧成形し加圧成形体を窒素ガス雰囲気中で９７５℃の温度で２時間焼成することによってイッテルビウム置換リン酸バナジウムリチウム燒結体を得た。このペレット状焼結体の両面に金電極をスパッタ法を用いて作製した。さらにその焼結体を恒温槽中にてＡＣインピーダンスアナライザーを用い、測定温度２５℃の条件で周波数に対するインピーダンスと位相角を測定した。これらの測定値をもとにナイキストプロットを描きその円弧より抵抗率を求め、この抵抗率からイオン伝導度を算出した。得られたイオン伝導度を、表１に示す。 (Evaluation of conductivity)
Further, the ytterbium-substituted lithium vanadium phosphate powder produced in Example 1 was pressure-molded into a circular pellet having a diameter of 10 mm under a pressure of 3.5 Mpa, and the pressure-molded body was heated in a nitrogen gas atmosphere at a temperature of 975° C. for 2 hours. By firing, a ytterbium-substituted lithium vanadium phosphate sintered body was obtained. Gold electrodes were formed on both surfaces of this pellet-shaped sintered body by a sputtering method. Furthermore, the impedance and phase angle with respect to frequency were measured for the sintered body using an AC impedance analyzer in a constant temperature bath under the condition of a measurement temperature of 25°C. Based on these measured values, a Nyquist plot was drawn, the resistivity was determined from the arc, and the ionic conductivity was calculated from this resistivity. The obtained ionic conductivity is shown in Table 1.
（全固体電池の作製と全固体電池の容量の測定）
　実施例１で作製したイッテルビウム置換リン酸バナジウムリチウム粉末を、正極活物質及び負極活物質として用いて、下記の方法により全固体電池を作製し、得られた全固体電池の容量を測定した。得られた全固体電池の容量を、表１に示す。 (Preparation of all-solid-state battery and measurement of capacity of all-solid-state battery)
Using the ytterbium-substituted lithium vanadium phosphate phosphate prepared in Example 1 as a positive electrode active material and a negative electrode active material, an all-solid battery was prepared by the following method, and the capacity of the obtained all-solid battery was measured. Table 1 shows the capacities of the obtained all-solid-state batteries.
（正極活物質層用ペースト及び負極活物質層用ペーストの作製）
　正極及び負極活物質層用ペーストは、イッテルビウム置換リン酸バナジウムリチウム粉末１００部に、バインダーとしてエチルセルロース１５部と、溶媒としてジヒドロターピネオール６５部とを加えて、三本ロールで混練・分散して正極、及び負極となる活物質層用ペーストを作製した。 (Preparation of paste for positive electrode active material layer and paste for negative electrode active material layer)
The positive electrode and negative electrode active material layer paste is 100 parts of ytterbium-substituted lithium vanadium phosphate powder, 15 parts of ethyl cellulose as a binder, and 65 parts of dihydroterpineol as a solvent are added, and the mixture is kneaded and dispersed with a three-roll roll to form a positive electrode. And the paste for active material layers used as a negative electrode was produced.
（固体電解質の作製）
　固体電解質として、以下の方法で作製したＬｉ１．３Ａｌ０．３Ｔｉ１．７（ＰＯ４）３を用いた。Ｌｉ２ＣＯ３、Ａｌ２Ｏ３、ＴｉＯ２、ＮＨ４Ｈ２ＰＯ４を出発原料とし、エタノール中を溶媒としてボールミルで１６時間湿式混合を行った。出発原料の混合粉末をボールとエタノールから分離し乾燥した後、アルミナ製坩堝中にて、８５０℃、２時間大気中で仮焼を行った。その後仮焼粉末を、粉砕のためエタノール中にてボールミル（１２０ｒｐｍ／ジルコニアボール）で１６時間処理を行った。粉砕粉末をボールとエタノールから分離、乾燥し粉末を得た。 (Preparation of solid electrolyte)
As the solid electrolyte, with Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 prepared by the following method. Li 2 CO 3 , Al 2 O 3 , TiO 2 , and NH 4 H 2 PO 4 were used as starting materials, and wet mixing was performed for 16 hours in a ball mill using ethanol as a solvent. The mixed powder of the starting materials was separated from the balls and ethanol, dried, and then calcined in an alumina crucible at 850° C. for 2 hours in the air. After that, the calcined powder was treated with a ball mill (120 rpm/zirconia ball) for 16 hours in ethanol for grinding. The ground powder was separated from the balls and ethanol and dried to obtain a powder.
（固体電解質層用ペーストの作製）
　次いで、この粉末１００部に、溶媒としてエタノール１００部、トルエン２００部をボールミルで加えて湿式混合した。その後ポリビニールブチラール系バインダー１６部とフタル酸ベンジルブチル４．８部をさらに投入し、混合して固体電解質層用ペーストを調合した。 (Preparation of solid electrolyte layer paste)
Next, to 100 parts of this powder, 100 parts of ethanol and 200 parts of toluene as a solvent were added by a ball mill and wet mixed. Thereafter, 16 parts of polyvinyl butyral binder and 4.8 parts of benzylbutyl phthalate were further added and mixed to prepare a solid electrolyte layer paste.
（固体電解質層用シートの作製）
　この固体電解質層用ペーストをドクターブレード法でＰＥＴフィルムを基材としてシート成形し、厚さ１５μｍの固体電解質層用シートを得た。 (Preparation of sheet for solid electrolyte layer)
This solid electrolyte layer paste was formed into a sheet by a doctor blade method using a PET film as a base material to obtain a solid electrolyte layer sheet having a thickness of 15 μm.
（正極集電体層用ペースト及び負極集電体層用ペーストの作製）
　Ｃｕ粉とイッテルビウム置換リン酸バナジウムリチウム粉末を重量比で１００：９となるように混合した後、バインダーとしてエチルセルロース１０部と、溶媒としてジヒドロターピネオール５０部を加えて三本ロール混合・分散して正極集電体層用ペースト及び負極集電体層用ペーストを作製した。 (Preparation of positive electrode current collector layer paste and negative electrode current collector layer paste)
After mixing the Cu powder and the ytterbium-substituted lithium vanadium phosphate powder in a weight ratio of 100:9, 10 parts of ethyl cellulose as a binder and 50 parts of dihydroterpineol as a solvent were added and mixed and dispersed in a three-roll roll to produce a positive electrode. A current collector layer paste and a negative electrode current collector layer paste were produced.
（活物質層ユニットの作製）
　上記の固体電解質層用シート上に、スクリーン印刷により厚さ５μｍで電極集電体層用ペーストを印刷し、８０℃で１０分間乾燥した。その上に、スクリーン印刷により厚さ５μｍで正極活物質層用ペーストを印刷し、８０℃で１０分間乾燥し正極層ユニットとした。一方、固体電解質層用シート上に、スクリーン印刷により厚さ５μｍで負極活物質層用ペーストを印刷し、８０℃で１０分間乾燥し、次に、その上に、スクリーン印刷により厚さ５μｍで電極集電体層用ペーストを印刷し、８０℃で、１０分間乾燥し、負極層ユニットとした。次いでＰＥＴフィルムを剥離した。 (Preparation of active material layer unit)
An electrode current collector layer paste having a thickness of 5 μm was printed on the above solid electrolyte layer sheet by screen printing and dried at 80° C. for 10 minutes. Then, a positive electrode active material layer paste having a thickness of 5 μm was printed by screen printing and dried at 80° C. for 10 minutes to obtain a positive electrode layer unit. On the other hand, a paste for negative electrode active material layer having a thickness of 5 μm is printed by screen printing on a sheet for solid electrolyte layer, dried at 80° C. for 10 minutes, and then an electrode having a thickness of 5 μm is printed by screen printing. The current collector layer paste was printed and dried at 80° C. for 10 minutes to obtain a negative electrode layer unit. Then, the PET film was peeled off.
（積層体の作製）
　正極層ユニット、負極層ユニットおよび固体電解質層用シートを用いて、固体電解質層、正極集電体層、正極活物質層、固体電解質層、負極活物質層、負極集電体層、固体電解質層の順に形成されるように積み重ね積層体を得た。このとき、正極層ユニットの正極集電体層が一方の端面にのみ延出し、負極活物質層ユニットの負極集電体層が他方の端面にのみ延出するように、各ユニットをずらして積み重ねた。その後、これを熱圧着により成形した後、切断して積層体を作製した。 (Preparation of laminated body)
Using the positive electrode layer unit, the negative electrode layer unit and the solid electrolyte layer sheet, a solid electrolyte layer, a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, a negative electrode current collector layer, a solid electrolyte layer A stacked laminate was obtained so as to be formed in the order of. At this time, the units are stacked in a staggered manner so that the positive electrode current collector layer of the positive electrode layer unit extends only on one end face and the negative electrode current collector layer of the negative electrode active material layer unit extends only on the other end face. It was Then, this was molded by thermocompression bonding and then cut to prepare a laminate.
（焼結体の作製）
　得られた積層体に脱バインダーを行った後、同時焼成して焼結体を得た。脱バインダーは窒素中５０℃／時間で焼成温度７００℃まで昇温して、その温度に１０時間保持し、同時焼成は、窒素中で昇温速度２００℃／時間で焼成温度８５０℃まで昇温して、その温度に１時間保持し、焼成後は自然冷却した。同時焼成後の電池外観サイズは、３．２ｍｍ×２．５ｍｍ×０．４ｍｍであった。 (Preparation of sintered body)
After removing the binder from the obtained laminated body, it was co-fired to obtain a sintered body. The debinder is heated in nitrogen at a temperature of 50° C./hour to a firing temperature of 700° C. and held at that temperature for 10 hours. Simultaneous firing is performed in nitrogen at a heating rate of 200° C./hour to a firing temperature of 850° C. Then, the temperature was maintained for 1 hour, and after firing, it was naturally cooled. The external appearance size of the battery after co-firing was 3.2 mm×2.5 mm×0.4 mm.
（充放電特性の評価）
　得られた積層体の焼結体（全固体電池）について、充放電試験器を用い、バネ付けピンで固定するタイプの治具に取り付け充放電容量を測定した。測定条件として、充放電時の電流は、いずれも２μＡで行い、電圧は０Ｖから１．８Ｖで行った。表１に測定した放電容量を示した。使用に十分な放電特性の閾値は３．６μＡｈである。 (Evaluation of charge/discharge characteristics)
The sintered body (all-solid-state battery) of the obtained laminated body was attached to a jig of a type fixed with a spring-loaded pin using a charge/discharge tester, and the charge/discharge capacity was measured. As the measurement conditions, the current during charging/discharging was 2 μA, and the voltage was 0 V to 1.8 V. Table 1 shows the measured discharge capacity. The threshold value of the discharge characteristic sufficient for use is 3.6 μAh.
［実施例２～２３、比較例１～９］
　活物質材料の作製において、目的とする活物質材料の組成、原料、を表１および２に記載したものとした以外は実施例１と同様の条件、方法で焼結体を作製し、また同様の条件、方法で各種の値を評価した。その結果を表１および２に示す。なお、表１及び表２において、ａは、一般式（Ｉ）におけるａの値である。 [Examples 2 to 23, Comparative Examples 1 to 9]
In the production of the active material, a sintered body was produced under the same conditions and methods as in Example 1 except that the composition and raw material of the active material of interest were those described in Tables 1 and 2, and the same. Various values were evaluated according to the conditions and method. The results are shown in Tables 1 and 2. In Tables 1 and 2, a is the value of a in the general formula (I).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
［実施例２４］
（有機溶媒電解質電池の作製）
＜正極の作製＞
　実施例１で作製したＬｉ３Ｖ１．９７Ｙｂ０．０３（ＰＯ４）３を正極活物質として、正極を作製した。Ｌｉ３Ｖ１．９７Ｙｂ０．０３（ＰＯ４）３を８５ｇ、カーボンブラック（電気化学工業（株）製、ＤＡＢ５０）を５ｇ、黒鉛（ティムカル（株）製　、商品名：ＫＳ－６）を５ｇ、及びバインダーのポリフッ化ビニリデン（ＰＶＤＦ）溶液（呉羽化学工業（株）製、商品名：ＫＦ７３０５、ＰＶＤＦを５質量％含んだＮＭＰ溶液）を５０ｇ、樹脂製容器に秤量し、ハイブリッドミキサーで混合して塗料を作製した。この塗料を集電体であるアルミニウム箔（厚み２０μｍ）にドクターブレード法で塗布後、９０℃で乾燥し、圧延した。なお、集電体には外部引き出し端子（リード）を溶接するために、塗料を塗布しない部分を設けておいた。 [Example 24]
(Preparation of organic solvent electrolyte battery)
<Production of positive electrode>
A positive electrode was produced using Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 produced in Example 1 as the positive electrode active material. Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 85 g, carbon black (manufactured by Denki Kagaku Kogyo KK, DAB50) 5 g, graphite (Timcal KK, trade name: KS-6) 5 g of polyvinylidene fluoride (PVDF) solution of binder (Kureha Chemical Industry Co., Ltd., trade name: KF7305, NMP solution containing 5% by mass of PVDF) was weighed in a resin container and mixed with a hybrid mixer. Then, a paint was prepared. This paint was applied to an aluminum foil (thickness 20 μm) as a current collector by the doctor blade method, dried at 90° C., and rolled. In addition, in order to weld the external lead terminal (lead), the current collector was provided with a portion to which no paint was applied.
　＜負極の作製＞
　実施例１で作製したＬｉ３Ｖ１．９７Ｙｂ０．０３（ＰＯ４）３を負極活物質として、負極を作製した。Ｌｉ３Ｖ１．９７Ｙｂ０．０３（ＰＯ４）３、カーボンブラック（電気化学工業（株）製、ＤＡＢ５０）及びバインダーのポリアクリル酸の１５質量％水溶液をそれぞれ１０ｇ、０．２３１ｇ及び７．５８４ｇ樹脂製容器に秤量し、自転公転する撹拌装置（（株）キーエンス製　商品名：ハイブリッドミキサー）で混合して塗料を作製した。この塗料を集電体である銅箔（厚み１０μｍ）にドクターブレード法で塗布後、９０℃で乾燥し、線圧６００ｋｇｆ／ｃｍで圧延した。この負極を、真空雰囲気下、１５０℃で２０時間熱処理した。
　なお、集電体には外部引き出し端子（リード）を溶接するために、塗料を塗布しない部分を設けておいた。 <Production of negative electrode>
A negative electrode was produced using Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 produced in Example 1 as the negative electrode active material. Li 3 V 1.97 Yb 0.03 (PO 4 ) 3 , carbon black (DAB50 manufactured by Denki Kagaku Kogyo Co., Ltd.), and 10 g, 0.231 g, and 7% of 15 mass% aqueous solutions of polyacrylic acid as a binder, respectively. A 584 g resin container was weighed and mixed with a stirrer (manufactured by KEYENCE CORPORATION, product name: hybrid mixer) that revolves around its axis to prepare a coating material. This paint was applied to a copper foil (thickness 10 μm) as a current collector by the doctor blade method, dried at 90° C., and rolled at a linear pressure of 600 kgf/cm. This negative electrode was heat-treated in a vacuum atmosphere at 150° C. for 20 hours.
In addition, in order to weld the external lead terminal (lead), the current collector was provided with a portion to which no paint was applied.
＜電池の作製＞
　上述のように作製した正極、負極及びセパレータ（ポリオレフィン製の微多孔質膜）を所定の寸法に切断した。続いて、正極、負極、及びセパレータをこの順序で積層した。積層するときには、正極、負極、及びセパレータがずれないようにホットメルト接着剤（エチレン－メタアクリル酸共重合体）を少量塗布し固定した。正極及び負極には、それぞれ、外部引き出し端子としてアルミニウム箔、ニッケル箔を超音波溶接した。外部端子と外装体とのシール性を向上させるために、この外部引き出し端子に、無水マレイン酸をグラフト化したポリプロピレン（ＰＰ）を巻き付け熱接着させた。正極、負極、及びセパレータを積層した電池要素を封入する電池外装体はアルミニウムラミネート材料からなり、その構成は、ＰＥＴ／Ａｌ／ＰＰのものを用意した（ＰＥＴは、ポリエチレンテレフタレートの略称である）。この時、ＰＰが内側となるように製袋した。この外装体の中に電池要素を入れ電解質溶液（エチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）の混合溶媒（ＥＣ：ＤＥＣ＝３０：７０ｖｏｌ％）にＬｉＰＦ６を１Ｍになるように溶解させた電解液）を適当量添加し、外装体を真空密封しリチウムイオン二次電池を作製した。 <Production of battery>
The positive electrode, the negative electrode, and the separator (microporous film made of polyolefin) produced as described above were cut into predetermined dimensions. Then, the positive electrode, the negative electrode, and the separator were laminated in this order. At the time of stacking, a small amount of hot melt adhesive (ethylene-methacrylic acid copolymer) was applied and fixed so that the positive electrode, the negative electrode, and the separator were not displaced. An aluminum foil and a nickel foil were ultrasonically welded to the positive electrode and the negative electrode as external lead terminals, respectively. In order to improve the sealing property between the external terminal and the exterior body, polypropylene (PP) grafted with maleic anhydride was wrapped around and thermally bonded to the external lead terminal. The battery exterior body enclosing the battery element in which the positive electrode, the negative electrode, and the separator were laminated was made of an aluminum laminate material, and the composition thereof was PET/Al/PP (PET is an abbreviation for polyethylene terephthalate). At this time, the bag was made so that PP was on the inside. Electrolysis in which a battery element was placed in this outer package and LiPF 6 was dissolved to 1M in an electrolyte solution (a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (EC:DEC=30:70 vol %)). Liquid) was added in an appropriate amount, and the outer casing was vacuum-sealed to produce a lithium ion secondary battery.
（電池試験方法）
　充放電試験は、２５℃の恒温槽内にて行い、充放電時の電流は、いずれも２μＡで行い、電圧は０．５Ｖから１．８Ｖで行った。測定された放電容量は７．１μＡｈであった。なお、使用に十分な放電特性の閾値は３．６μＡｈである。 (Battery test method)
The charge/discharge test was conducted in a constant temperature bath at 25° C., the current during charge/discharge was 2 μA, and the voltage was 0.5 V to 1.8 V. The measured discharge capacity was 7.1 μAh. The threshold value of the discharge characteristic sufficient for use is 3.6 μAh.
［比較例１０］
　比較例１で作製したＬｉ３Ｖ２（ＰＯ４）３を活物質として、正極および負極を作製した以外は、実施例２４と同様の条件、方法でリチウムイオン二次電池を作製し、実施例２４と同様の方法で放電容量を測定した。測定された放電容量は３．４μＡｈであった。 [Comparative Example 10]
A lithium ion secondary battery was produced under the same conditions and method as in Example 24, except that the positive electrode and the negative electrode were produced using Li 3 V 2 (PO 4 ) 3 produced in Comparative Example 1 as the active material. The discharge capacity was measured in the same manner as in 24. The measured discharge capacity was 3.4 μAh.
　以上のように、本発明に係る電池は放電容量の向上に効果がある。高容量な電池を提供することにより、特に、エレクトロニクスの分野で大きく寄与する。 As described above, the battery according to the present invention is effective in improving the discharge capacity. Providing a high-capacity battery makes a great contribution, especially in the field of electronics.
　１　正極層
　１Ａ　正極集電体層
　１Ｂ　正極活物質層
　２　負極層
　２Ａ　負極集電体層
　２Ｂ　負極活物質層
　３　固体電解質
　４　積層体
　５，６　端子電極
　１０　全固体電池
　１１　正極
　１２　正極集電体
　１４　正極活物質層
　１８　セパレータ
　２１　負極
　２２　負極集電体
　２４　負極活物質層
　３０　発電要素
　５０　ケース
　６０　正極リード
　６２　負極リード
　１００　リチウムイオン二次電池 DESCRIPTION OF SYMBOLS 1 Positive electrode layer 1A Positive electrode current collector layer 1B Positive electrode active material layer 2 Negative electrode layer 2A Negative electrode current collector layer 2B Negative electrode active material layer 3 Solid electrolyte 4 Laminated body 5,6 Terminal electrode 10 All solid state battery 11 Positive electrode 12 Positive electrode current collector 14 Positive electrode active material layer 18 Separator 21 Negative electrode 22 Negative electrode current collector 24 Negative electrode active material layer 30 Power generating element 50 Case 60 Positive electrode lead 62 Negative electrode lead 100 Lithium ion secondary battery

Claims (4)

  1. 　ポリリン酸化合物であるリン酸バナジウムリチウムを含み、
    　前記リン酸バナジウムリチウムは下記の式（１）～（３）の全てを満たす、活物質材料。
    　１＜（Ａ／Ａ０）≦１．００３０　（１）
    　１＜（Ｂ／Ｂ０）≦１．００５１　（２）
    　１＜（Ｃ／Ｃ０）≦１．００４３　（３）
    　式（１）～（３）において、Ａは、前記リン酸バナジウムリチウムの結晶軸におけるａ軸の長さを表し、Ａ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるａ軸の長さを表し、Ｂは、前記リン酸バナジウムリチウムの結晶軸におけるｂ軸の長さを表し、Ｂ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるｂ軸の長さを表し、Ｃは、前記リン酸バナジウムリチウムの結晶軸におけるｃ軸の長さを表し、Ｃ０は、無置換のＬｉ３Ｖ２（ＰＯ４）３の結晶軸におけるｃ軸の長さを表す。     Including lithium vanadium phosphate, which is a polyphosphate compound,
    The lithium vanadium phosphate is an active material material that satisfies all of the following formulas (1) to (3).
    1 <(A/A0) ≤ 1.0030 (1)
    1<(B/B0)≦1.0051 (2)
    1<(C/C0)≦1.043 (3)
    In formulas (1) to (3), A represents the length of the a-axis in the crystal axis of the lithium vanadium phosphate, and A0 represents a in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. Represents the length of the axis, B represents the length of the b axis in the crystal axis of the lithium vanadium phosphate, and B0 represents the length of the b axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. C represents the length of the c-axis in the crystal axis of the lithium vanadium phosphate, and C0 represents the length of the c-axis in the crystal axis of unsubstituted Li 3 V 2 (PO 4 ) 3. ..
  2. 　前記リン酸バナジウムリチウムは、バナジウムの一部が、Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂからなる群より選ばれる少なくとも一つの元素で置換されている、請求項１に記載の活物質材料。 The lithium vanadium phosphate has a part of vanadium substituted with at least one element selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb. Active material.
  3. 　前記リン酸バナジウムリチウムの主相が、下記の一般式（Ｉ）を満たす、請求項２に記載の活物質材料。
    　Ｌｉ３＋ａ（Ｖ２－ｘＭｘ）（ＰＯ４）３　（Ｉ）
    　一般式（Ｉ）において、Ｍは、Ｙ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂからなる群より選ばれる少なくとも一つの元素を表し、ｘは、０＜ｘ≦０．３を満たす数を表し、ａは、－３．０＜ａ＜３．０を満たす数を表す。     The active material material according to claim 2, wherein the main phase of the lithium vanadium phosphate satisfies the following general formula (I).
    Li 3+a (V 2-x M x )(PO 4 ) 3 (I)
    In the general formula (I), M represents at least one element selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, and Yb, and x satisfies 0<x≦0.3. Represents a number, and a represents a number satisfying −3.0<a<3.0.
  4. 　請求項１～３の何れか一項に記載の活物質材料を含む電極層と、固体電解質層とを備える、全固体電池。 An all-solid-state battery comprising an electrode layer containing the active material according to any one of claims 1 to 3 and a solid electrolyte layer.
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