WO2021114172A1 - Negative electrode material, preparation method therefor, negative electrode piece, and electrochemical apparatus - Google Patents

Negative electrode material, preparation method therefor, negative electrode piece, and electrochemical apparatus Download PDF

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WO2021114172A1
WO2021114172A1 PCT/CN2019/124830 CN2019124830W WO2021114172A1 WO 2021114172 A1 WO2021114172 A1 WO 2021114172A1 CN 2019124830 W CN2019124830 W CN 2019124830W WO 2021114172 A1 WO2021114172 A1 WO 2021114172A1
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silicon
sulfide
negative electrode
electrode material
metal
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PCT/CN2019/124830
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French (fr)
Chinese (zh)
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张成波
鲁宇浩
谢远森
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宁德新能源科技有限公司
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Priority to PCT/CN2019/124830 priority Critical patent/WO2021114172A1/en
Publication of WO2021114172A1 publication Critical patent/WO2021114172A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • 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

  • This application relates to the technical field of lithium ion batteries, and in particular to a negative electrode material, a preparation method thereof, a negative electrode pole piece and an electrochemical device.
  • Lithium-ion batteries are now widely used as mobile electronic devices, such as smart phones, notebook computers, etc., and have a huge market in the field of grid energy storage and electric vehicles.
  • Anode materials are an important part of lithium-ion batteries.
  • carbon materials have been widely used as anode materials, but recently the market has requested to further increase battery capacity.
  • silicon As a negative electrode material is being extensively studied. The reason is that the theoretical capacity of the silicon-based anode material reaches 4200 mAh/g, which is much higher than the theoretical capacity of the carbon material (372 mAh/g), so it can be expected to greatly increase the battery capacity of lithium-ion batteries.
  • the silicon-based negative electrode material will undergo violent volume expansion (up to 300%) during the lithium extraction/intercalation reaction process, which will cause structural damage and powdering of the negative electrode material, and cause problems such as shortened cycle life.
  • the purpose of this application is to provide a negative electrode material to improve the cycle performance of the silicon-based negative electrode material. Further, this application also provides a preparation method of the negative electrode material, a negative electrode piece, an electrochemical device and an electronic device.
  • the first aspect of the present application provides a negative electrode material, which comprises a silicon-based material and a metal sulfide; wherein the particle size of the metal sulfide ranges from 0.05 ⁇ m ⁇ D50 ⁇ 10 ⁇ m, preferably 1 ⁇ m ⁇ D50 ⁇ 8 ⁇ m; Preferably, it is 2 ⁇ m ⁇ D50 ⁇ 6 ⁇ m.
  • the metal sulfide includes zinc sulfide, copper sulfide, cuprous sulfide, iron sulfide, ferrous sulfide, manganese sulfide, potassium sulfide, sodium sulfide, magnesium sulfide, calcium sulfide, strontium sulfide, At least one of barium sulfide or tin sulfide.
  • the content of the metal sulfide is 0.5-12% by weight, preferably 1-10% by weight, more preferably 3-8% by weight .
  • the content of the metal element is 0.1-8 wt%, preferably 2-6 wt%.
  • the content of sulfur is 0.1-6 wt%, preferably 1-4 wt%.
  • the silicon-based material may include at least one of silicon oxide, silicon, silicon-carbon composite material, or silicon alloy.
  • the surface of the silicon oxide has a carbon-containing material.
  • silicon oxide is a material represented by SiO x , where 0 ⁇ x ⁇ 2, preferably 0.5 ⁇ x ⁇ 1.6.
  • the pure silicon includes at least one of silicon microparticles, silicon nanoparticles, silicon nanowires, or silicon nanofilms;
  • the silicon alloy includes at least one of silicon-iron alloy, silicon-aluminum alloy, silicon-nickel alloy, or silicon-iron-aluminum alloy.
  • the particle size range of the silicon oxide is: 1 ⁇ m ⁇ D50 ⁇ 10 ⁇ m.
  • the specific surface area of silicon oxide is less than 10 m 2 /g.
  • the silicon-based material has metal sulfides on the surface.
  • the silicon-based material has a non-porous structure.
  • the second aspect of the present application also provides the preparation method of the negative electrode material provided in the foregoing first aspect, which includes mixing a silicon-based material with a metal sulfide.
  • the third aspect of the present application also provides a negative pole piece, which includes a current collector and a negative active material film coated on at least one surface of the current collector, the negative active material film comprising the above-mentioned negative electrode material.
  • the fourth aspect of the present application also provides an electrochemical device, which comprises the above-mentioned negative pole piece.
  • the fifth aspect of the present application also provides an electronic device, which includes the electrochemical device described above.
  • silicon-carbon composite material refers to a material composed of silicon and carbon, especially a granular material.
  • the silicon can be silicon with any morphology, and the carbon can be soft carbon or hard carbon or graphite or a combination thereof.
  • the morphology of the composite silicon-carbon material is not limited, and it can be porous, spherical or random granular.
  • silicon alloy refers to an alloy composition formed of silicon and at least one metal; including but not limited to silicon-iron alloy, silicon-aluminum alloy, silicon-nickel alloy, or silicon-iron-aluminum alloy.
  • silicon microparticles refers to silicon particles with a particle size in the micron range, especially silicon particles with a particle size in the range of 1-100 ⁇ m.
  • silicon nanoparticle refers to silicon particles with a particle size in the nanometer range, especially silicon particles with a particle size in the range of 1-1000 nm;
  • silicon nanosphere refers to a silicon nanoparticle with a morphology close to a spherical shape.
  • silicon nanowire refers to a silicon nanomaterial with a one-dimensional linear structure, and its wire diameter is generally in the range of 1-1000 nm.
  • silicon nano-film refers to a silicon nanomaterial with a two-dimensional planar structure composed of a large number of silicon nanoparticles.
  • D50 means the particle size at which the cumulative distribution of particles is 50%; that is, the volume content of particles smaller than this size accounts for 50% of all particles.
  • the particle size is measured with a laser particle size analyzer.
  • the term "coated” can be understood as at least partially coated, that is, it can be partially coated or fully coated; for example, when it is described that the outer surface of a silicon-based material can be coated with metal sulfide, it should be It is understood that the outer surface of the silicon-based material may be partially covered with metal sulfide or completely covered with metal sulfide.
  • the negative electrode material provided by the present application can improve the cycle performance of the negative electrode material by introducing metal sulfide.
  • the method for preparing the negative electrode material provided in the present application is simple to operate and easy to industrialize.
  • the negative pole piece and electrochemical device provided by the present application have good cycle performance.
  • Figure 1 shows an SEM image of the negative electrode material prepared in Example 3
  • Figure 5 shows the specific capacity curves of lithium intercalation in Example 3 and Comparative Example 1;
  • Figure 6 shows the specific capacity curves for delithiation of Example 3 and Comparative Example 1;
  • FIG. 7 shows a comparison curve of the cycle capacity retention rate of Example 3 and Comparative Example 1.
  • the negative electrode material of the present application is a negative electrode material used in the manufacture of electrochemical components, and is mainly used in electrochemical components such as lithium ion batteries and electric double layer capacitors.
  • the negative electrode material of one embodiment of the present application includes silicon-based materials and metal sulfides; wherein the particle size range of the metal sulfides is 0.05 ⁇ m ⁇ D50 ⁇ 10 ⁇ m, preferably 1 ⁇ m ⁇ D50 ⁇ 8 ⁇ m; more preferably 2 ⁇ m ⁇ D50 ⁇ 6 ⁇ m .
  • the inventor of the present application found that by introducing metal sulfide into the silicon-based material, the cycle performance of the negative electrode material can be effectively improved.
  • the silicon-based material is used as a negative electrode material, the expansion and contraction in the process of lithium insertion and removal is very large, which causes damage to the silicon-based material during the charge and discharge process, resulting in poor cycle performance.
  • the cycle performance is significantly improved. Not limited to any theory, it can be considered that during the first lithium insertion process, metal sulfide reacts with lithium ions to produce elemental metal and lithium sulfide.
  • lithium sulfide as a buffer medium can play a role in alleviating the expansion of lithium insertion in the negative electrode; the presence of elemental metal elements can enhance the conductivity and ion conductivity of the negative electrode active membrane, thereby improving the conductive network of the negative electrode active membrane, thereby improving the negative electrode Cycle performance.
  • the inventor of the present application found that when the particle size of the metal sulfide is large, the discharge specific capacity and cycle performance of the negative electrode material will be reduced. When the particle size of the metal sulfide is too small, it will bring difficulties to the preparation of the negative electrode material.
  • the metal sulfide includes zinc sulfide, copper sulfide, cuprous sulfide, iron sulfide, ferrous sulfide, manganese sulfide, potassium sulfide, sodium sulfide, magnesium sulfide, calcium sulfide, strontium sulfide, barium sulfide Or at least one of tin sulfide.
  • the metal sulfide may be used alone or in combination of two or more.
  • the inventor of the present application also found that as the metal sulfide content increases, the first coulombic efficiency increases, and after reaching the peak value, it begins to decrease. Taking zinc sulfide as an example, this peak appears when the zinc sulfide content is around 5 wt%. Not limited to any theory, it can be considered that this is because the addition of metal sulfide can reduce the polarization to a certain extent, as shown in Figure 5 and Figure 6, especially it can reduce the polarization in the delithiation process to a certain extent. , This can increase the delithiation capacity to a certain extent, thereby increasing the first coulombic efficiency.
  • the content of metal sulfide should be controlled.
  • the content of the metal sulfide may be 0.5-12% by weight, preferably 1-10% by weight, more preferably 3-8% by weight.
  • the battery cycle characteristics are significantly improved.
  • the content of the metal element may be 0.1-8 wt%, preferably 2-6 wt%.
  • the content of sulfur may be 0.1-6 wt%, preferably 1-4 wt%.
  • the obtained negative electrode material can significantly improve the battery cycle performance and increase the first-time coulombic efficiency.
  • the silicon-based material may include at least one of silicon oxide, silicon, silicon-carbon composite material, or silicon alloy. These silicon-based materials can be used alone or in combination of two or more.
  • the silicon-based materials used in this application are all materials known in the art; they can be prepared according to the prior art or obtained through commercial channels.
  • the silicon-based material used is preferably a non-porous structure.
  • the use of non-porous silicon-based materials can increase the density of the produced negative pole piece, further improve the structural stability, and withstand greater external pressure.
  • silicon oxide is a material represented by SiO x , where 0 ⁇ x ⁇ 2, preferably 0.5 ⁇ x ⁇ 1.6.
  • the silicon oxide has a carbon material on the surface, and the silicon oxide may be partially or completely coated with carbon.
  • Carbon coating can increase the conductivity of silicon oxide and improve its electrical properties.
  • Carbon-coated silicon oxide is a material known in the art; it can be prepared according to the prior art or obtained through commercial channels.
  • the particle size range of the silicon oxide is preferably 1 ⁇ m ⁇ D50 ⁇ 10 ⁇ m.
  • the specific surface area of silicon oxide is preferably less than 10 m 2 /g.
  • silicon may include at least one of silicon microparticles, silicon nanoparticles, silicon nanowires, or silicon nanofilms. These silicons may be used alone or in combination of two or more.
  • the silicon nanoparticles may be silicon nanospheres.
  • the silicon alloy may include at least one of silicon-iron alloy, silicon-aluminum alloy, silicon-nickel alloy, or silicon-iron-aluminum alloy. These silicon alloys may be used alone or in combination of two or more kinds.
  • the surface of the silicon-based material has metal sulfide, and part or all of the metal sulfide may be coated on at least a part of the surface of the silicon-based material.
  • the silicon-based material and the metal sulfide in the mixture are in a state of being uniformly dispersed with each other.
  • at least part of the outer surface of the silicon-based material may be coated with metal sulfide; further, it is not excluded that the silicon-based material and the coated metal sulfide will have a chemical reaction.
  • This application also provides a method for preparing the above-mentioned negative electrode material, which includes mixing a silicon-based material with a metal sulfide to obtain the above-mentioned negative electrode material provided in this application.
  • the mixing in the above preparation method can be carried out by any method known to those skilled in the art, and is not particularly limited, as long as the silicon-based material of the present application and the metal sulfide can be uniformly mixed, such as various dry mixing or wet mixing.
  • Method mixing can be carried out by any mixing equipment known to those skilled in the art, and is not particularly limited.
  • a ball mill, a planetary ball mill, a V-shaped mixer, a three-dimensional mixer, an airflow mixer, or a horizontal mixer can be used.
  • Mixing equipment is known in the art for mixing.
  • a ball mill or a planetary ball mill is used for mixing.
  • a V-type mixer, a three-dimensional mixer, an airflow mixer, or a horizontal mixer may be used for dry premixing, and then ball milling.
  • the mixing time is not particularly limited, as long as the negative electrode material of the present application can be mixed uniformly.
  • the preparation method of the negative electrode material provided in this application is simple and easy to implement and easy to industrialize.
  • the present application provides a negative electrode sheet, which includes a current collector and a negative active material film coated on at least one surface of the current collector, and the negative active material film includes the above-mentioned negative electrode material provided in the present application.
  • the current collector is not particularly limited, and any current collector known to those skilled in the art can be used. Specifically, for example, a current collector formed of iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum, or the like can be used. Among them, as the negative electrode current collector, copper foil or copper alloy foil is particularly preferred. The above-mentioned materials may be used singly or in combination of two or more in any ratio.
  • the negative active material film may further include a conductive agent.
  • the conductive agent is not particularly limited, and may be any conductive agent or a combination known to those skilled in the art.
  • at least one of a zero-dimensional conductive agent, a one-dimensional conductive agent, and a two-dimensional conductive agent may be used.
  • the conductive agent may include at least one of carbon black, conductive graphite, carbon fiber, carbon nanotube, VGCF (Vapour Grown Carbon Fiber) or graphene.
  • the amount of the conductive agent is not particularly limited, and can be selected according to common knowledge in the art.
  • the above-mentioned conductive agent may be used alone or in combination of two or more in any ratio.
  • the negative active material film may further include a binder.
  • the binder is not particularly limited, and it can be any binder or combination known to those skilled in the art.
  • polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, and polyvinyl cellulose can be used.
  • Vinyl chloride carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, Styrene butadiene rubber, acrylic (ester) styrene butadiene rubber, epoxy resin or nylon, etc.
  • binders may be used alone or in combination of two or more in any ratio.
  • the preparation of the negative pole piece is well known to those skilled in the art; in this application, the preparation process of the negative pole piece includes: dispersing the negative electrode material, conductive agent and binder provided in this application in a certain mass ratio After the solvent is fully stirred and mixed uniformly, it is coated on the current collector, dried, and cold pressed to obtain a negative pole piece.
  • the solvent used is not particularly limited. For example, N-methylpyrrolidone, acetone or water can be used. These solvents may be used alone or in combination of two or more in any ratio.
  • the electrochemical device of the present application includes, but is not limited to: all kinds of primary batteries, secondary batteries, fuel cells, solar cells or capacitors.
  • a typical electrochemical device is a lithium ion battery, which is a secondary battery.
  • Electrochemical devices, such as lithium-ion batteries, generally include a negative pole piece, a positive pole piece, a separator, and an electrolyte.
  • the negative pole piece of the electrochemical device provided in this application adopts the negative pole piece provided in this application; and other components, including the positive pole piece, separator, electrolyte, etc., are not particularly limited.
  • the positive electrode material contained in the positive pole piece may include, but is not limited to, lithium cobaltate, lithium manganate, lithium iron phosphate, and the like.
  • the material of the diaphragm may include, but is not limited to, glass fiber, polyester, polyethylene, polypropylene, polytetrafluoroethylene, or a combination thereof.
  • the electrolyte generally includes organic solvents, lithium salts and additives.
  • the organic solvent may include, but is not limited to, at least one of ethylene carbonate, vinylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, or ethyl propionate.
  • the lithium salt may include at least one of an organic lithium salt or an inorganic lithium salt.
  • the lithium salt may include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium bistrifluoromethanesulfonimide LiN (CF 3 SO 2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), lithium bisoxalate borate LiB(C 2 O 4 ) 2 (LiBOB) or lithium difluorooxalate LiBF 2 At least one of (C 2 O 4 ) (LiDFOB).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiPO 2 F 2 lithium difluorophosphate
  • LiN CF 3 SO 2 ) 2
  • LiTFSI lithium bistrifluoromethanesulfonimide LiN (CF 3 SO 2 )
  • a secondary battery can be manufactured by the following process: overlap the positive electrode and the negative electrode via spacers, and place them in the battery container after winding, folding and other operations as needed, and inject the electrolyte into the battery container and seal it.
  • the negative electrode used is The above-mentioned negative pole piece provided in this application.
  • an overcurrent prevention element, a guide plate, etc. can also be placed in the battery container as needed, so as to prevent the internal pressure of the battery from rising and overcharging and discharging.
  • the application also provides an electronic device, which includes the electrochemical device provided in the application.
  • the electrochemical device may be a lithium ion battery provided in the present application.
  • the D50 of the metal sulfide used in the examples is 3 ⁇ m.
  • the negative electrode material the conductive agent SuperP: carboxymethyl cellulose is mixed in a weight ratio of 8:1:1, and water is added and mixed as a dispersion medium to obtain a negative electrode slurry with a solid content of 40%. Then, the above-mentioned negative electrode slurry was coated on a 10 ⁇ m copper current collector so that the film thickness after drying was 38 ⁇ m; then it was dried at 110°C; then it was calendered using a roller press to obtain a negative electrode active material film thickness of 30 ⁇ m negative pole piece.
  • the button half-cell assembly is carried out with metallic lithium as the counter electrode.
  • the isolation membrane adopts a ceramic-coated polyethylene (PE) material isolation membrane.
  • First Coulomb efficiency first discharge specific capacity/first charge specific capacity.
  • Example 1 The material ratio in Example 1 is changed to 97 parts by weight of SiO x and 3 parts by weight of zinc sulfide, and the rest is the same as in Example 1.
  • Example 1 The material ratio in Example 1 is changed to 95 parts by weight of SiO x and 5 parts by weight of zinc sulfide, and the rest is the same as in Example 1.
  • Fig. 1 shows a scanning electron micrograph of the negative electrode material of Example 3
  • Figs. 2-4 show the scanning electron microscope energy spectra of the silicon element, the sulfur element and the zinc element in the area of Fig. 1 respectively. It can be seen from Figure 2-4 that the silicon-based material and zinc sulfide form a uniformly mixed material.
  • Example 1 The material ratio in Example 1 is changed to 92 parts by weight of SiO x and 8 parts by weight of zinc sulfide, and the rest is the same as in Example 1.
  • Example 1 The material ratio in Example 1 is changed to 90 parts by weight of SiO x and 10 parts by weight of zinc sulfide, and the rest is the same as in Example 1.
  • Example 6 The material ratio in Example 6 is changed to 95 parts by weight of SiO x and 5 parts by weight of zinc sulfide, and the rest is the same as in Example 6.
  • Example 6 The material ratio in Example 6 is changed to 90 parts by weight of SiO x and 10 parts by weight of zinc sulfide, and the rest is the same as in Example 6.
  • Example 3 The zinc sulfide in Example 3 is replaced with copper sulfide with a D50 of 3 ⁇ m, and the rest is the same as in Example 3.
  • Example 3 The zinc sulfide in Example 3 was replaced with iron sulfide with a D50 of 3 ⁇ m, and the rest was the same as in Example 3.
  • Example 3 Replace the zinc sulfide in Example 3 with 1:1 zinc sulfide and copper sulfide whose D50 is 3 ⁇ m, and the rest is the same as in Example 3.
  • Example 1 The silicon material in Example 1 is replaced with silicon micron particles, the D50 is 4 ⁇ m, the specific surface area is 3 m2/g, and the rest is the same as in Example 1.
  • Example 12 The material ratio in Example 12 is changed to 97 parts by weight of silicon micron particles and 3 parts by weight of zinc sulfide, and the rest is the same as in Example 12.
  • Example 12 The material ratio in Example 12 is changed to 95 parts by weight of silicon micron particles and 5 parts by weight of zinc sulfide, and the rest is the same as in Example 12.
  • Example 3 The zinc sulfide in Example 3 was replaced with zinc sulfide with a D50 of 0.5 ⁇ m, and the rest was the same as in Example 3.
  • Example 3 The zinc sulfide in Example 3 was replaced with zinc sulfide with a D50 of 6 ⁇ m, and the rest was the same as in Example 3.
  • Example 3 The zinc sulfide in Example 3 was replaced with zinc sulfide with a D50 of 10 ⁇ m, and the rest was the same as in Example 3.
  • SiO X was used directly as the negative electrode material without ball milling, and the rest was the same as in Example 1.
  • SiO X was directly used as the negative electrode material, and the ball milling treatment was performed as described in Example 1, and the rest was the same as in Example 1.
  • the silicon micron particles were directly used as the negative electrode material without ball milling, and the rest was the same as in Example 1.
  • the silicon micron particles were directly used as the negative electrode material, and the ball milling process was performed as described in Example 1, and the rest was the same as in Example 1.
  • Table 1-4 lists the components, discharge specific capacity, first coulombic efficiency and capacity retention rate of each embodiment and comparative example.
  • FIG. 5 shows the lithium intercalation specific capacity curves of Example 3 and Comparative Example 1. It can be seen from FIG. 5 that compared with Comparative Example 1, the initial lithium insertion potential of Example 3 is higher, indicating that the lithium insertion polarization of Example 3 is lower than that of Comparative Example 1.
  • Figure 6 shows the delithiation specific capacity curves of Example 3 and Comparative Example 1. It can be seen from Figure 6 that, compared with Comparative Example 1, the voltage drop after delithiation in Example 3 is small, indicating the delithiation of Example 3 The lithium polarization is smaller than that of Comparative Example 1. It can be seen that the metallic zinc formed during the lithium insertion process of zinc sulfide increases the overall conductivity of the pole piece, which can reduce the polarization of the negative electrode material to a certain extent, especially to reduce the negative electrode material in the lithium removal process to a certain extent. Polarization, which can increase the delithiation capacity to a certain extent, thereby increasing the first coulombic efficiency.
  • FIG. 7 shows the cycle capacity retention rate using Example 3 and Comparative Example 1.
  • FIG. 7 shows the cycle capacity retention rate using Example 3 and Comparative Example 1.
  • the introduction of zinc sulfide can significantly improve the cycleability of the silicon-based negative electrode material. Without being limited to any theory, it can be considered that the lithium sulfide formed during the lithium intercalation process of zinc sulfide can serve as a buffer phase to slow down the lithium intercalation expansion of silicon.
  • the introduction of zinc sulfide brings a good conductive network (metallic zinc) and buffer phase, which can significantly improve the cycle performance of the negative pole piece.
  • Examples 6, 7, and 8 have the same discharge specific capacity and first-time coulombic efficiency change law. However, the cycle performance of Examples 6, 7, and 8 that were only subjected to dry mixing without ball milling treatment was significantly lower than that of Examples 1-5 that were subjected to ball milling treatment. Not limited to any theory, it can be considered that the ball milling treatment will cause the change of the surface state of the material.
  • At least a part of the outer surface of the silicon-based material is coated with zinc sulfide, or during the ball milling process, under the action of mechanical force, the silicon-based material and the vulcanization
  • a certain degree of chemical reaction of zinc makes the surface structure of the silicon-based material particles more stable, and further improves the cycle performance of the silicon-based anode material.

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Abstract

A negative electrode material, a preparation method therefor, a negative electrode piece, and an electrochemical apparatus. The negative electrode material comprises a silicon-based material and a metal sulfide, wherein the particle size range of the metal sulfide is 0.05μm≤D50≤10μm. The negative electrode material can effectively improve cycle performance. Additionally, the negative electrode preparation method is simple to operate and easy to industrialize. In addition, the negative electrode piece and the electrochemical apparatus have good cycle performances.

Description

一种负极材料、其制备方法、负极极片及电化学装置Anode material, preparation method thereof, anode pole piece and electrochemical device 技术领域Technical field
本申请涉及锂离子电池技术领域，特别是涉及一种负极材料、其制备方法、负极极片及电化学装置。This application relates to the technical field of lithium ion batteries, and in particular to a negative electrode material, a preparation method thereof, a negative electrode pole piece and an electrochemical device.
背景技术Background technique
锂离子电池现在被广泛用作移动电子设备，如智能手机、笔记本电脑等，并且在电网储能、电动汽车领域具有巨大的市场。Lithium-ion batteries are now widely used as mobile electronic devices, such as smart phones, notebook computers, etc., and have a huge market in the field of grid energy storage and electric vehicles.
负极材料是锂离子电池中的重要组成部分，传统上广泛使用碳材料作为负极材料，但最近市场上要求进一步提高电池容量。为了提高电池容量，使用硅作为负极材料正在得到广泛研究。原因在于硅基负极材料的理论容量达到4200mAh/g，远高于碳材料的理论容量(372mAh/g)，因此可以期待大幅度提高锂离子电池的电池容量。但是硅基负极材料在脱/嵌锂反应过程中会发生剧烈的体积膨胀(高达300％)，会导致负极材料的结构破坏与粉化，造成循环寿命缩短等问题。Anode materials are an important part of lithium-ion batteries. Traditionally, carbon materials have been widely used as anode materials, but recently the market has requested to further increase battery capacity. In order to increase battery capacity, the use of silicon as a negative electrode material is being extensively studied. The reason is that the theoretical capacity of the silicon-based anode material reaches 4200 mAh/g, which is much higher than the theoretical capacity of the carbon material (372 mAh/g), so it can be expected to greatly increase the battery capacity of lithium-ion batteries. However, the silicon-based negative electrode material will undergo violent volume expansion (up to 300%) during the lithium extraction/intercalation reaction process, which will cause structural damage and powdering of the negative electrode material, and cause problems such as shortened cycle life.
发明内容Summary of the invention
本申请的目的在于提供一种负极材料，以改善硅基负极材料的循环性能。进一步地，本申请还提供了所述负极材料的制备方法、负极极片、电化学装置及电子设备。The purpose of this application is to provide a negative electrode material to improve the cycle performance of the silicon-based negative electrode material. Further, this application also provides a preparation method of the negative electrode material, a negative electrode piece, an electrochemical device and an electronic device.
本申请第一方面提供了一种负极材料，其包含硅基材料和金属硫化物；其中，所述金属硫化物的粒径范围为0.05μm≤D50≤10μm，优选为1μm≤D50≤8μm；更优选为2μm≤D50≤6μm。The first aspect of the present application provides a negative electrode material, which comprises a silicon-based material and a metal sulfide; wherein the particle size of the metal sulfide ranges from 0.05 μm≤D50≤10μm, preferably 1μm≤D50≤8μm; Preferably, it is 2 μm≦D50≦6 μm.
在本申请的一些实施方式中，所述金属硫化物包括硫化锌、硫化铜、硫化亚铜、硫化铁、硫化亚铁、硫化锰、硫化钾、硫化钠、硫化镁、硫化钙、硫化锶、硫化钡或硫化锡中的至少一种。In some embodiments of the present application, the metal sulfide includes zinc sulfide, copper sulfide, cuprous sulfide, iron sulfide, ferrous sulfide, manganese sulfide, potassium sulfide, sodium sulfide, magnesium sulfide, calcium sulfide, strontium sulfide, At least one of barium sulfide or tin sulfide.
在本申请的一些实施方式中，以所述负极材料的总重量为基准，所述金属硫化物的含量为0.5-12重量％，优选为1-10重量％，更优选为3-8重量％。In some embodiments of the present application, based on the total weight of the negative electrode material, the content of the metal sulfide is 0.5-12% by weight, preferably 1-10% by weight, more preferably 3-8% by weight .
在本申请的一些实施方式中，以所述负极材料的总重量为基准，金属元素的含量为0.1-8重量％，优选为2-6重量％。In some embodiments of the present application, based on the total weight of the negative electrode material, the content of the metal element is 0.1-8 wt%, preferably 2-6 wt%.
在本申请的一些实施方式中，其中，以所述负极材料的总重量为基准，硫元素的含量为0.1-6重量％，优选为1-4重量％。In some embodiments of the present application, based on the total weight of the negative electrode material, the content of sulfur is 0.1-6 wt%, preferably 1-4 wt%.
在本申请的一些实施方式中，所述硅基材料可以包括硅氧化物、硅、硅碳复合材料或硅合金中的至少一种。In some embodiments of the present application, the silicon-based material may include at least one of silicon oxide, silicon, silicon-carbon composite material, or silicon alloy.
在本申请的一些实施方式中，其中，所述硅氧化物表面具有含碳材料。In some embodiments of the present application, wherein the surface of the silicon oxide has a carbon-containing material.
在本申请的一些实施方式中，硅氧化物为以SiO x表示的材料，其中0<x<2，优选0.5≤x≤1.6。 In some embodiments of the present application, silicon oxide is a material represented by SiO x , where 0<x<2, preferably 0.5≤x≤1.6.
在本申请的一些实施方式中，所述纯硅包括硅微米颗粒、硅纳米颗粒、硅纳米线或硅纳米薄膜中的至少一种；In some embodiments of the present application, the pure silicon includes at least one of silicon microparticles, silicon nanoparticles, silicon nanowires, or silicon nanofilms;
所述硅合金包括硅铁合金、硅铝合金、硅镍合金或硅铁铝合金中的至少一种。The silicon alloy includes at least one of silicon-iron alloy, silicon-aluminum alloy, silicon-nickel alloy, or silicon-iron-aluminum alloy.
在本申请的一些实施方式中，硅氧化物的粒径范围为：1μm≤D50≤10μm。In some embodiments of the present application, the particle size range of the silicon oxide is: 1 μm≦D50≦10 μm.
在本申请的一些实施方式中，硅氧化物的比表面积小于10m 2/g。 In some embodiments of the present application, the specific surface area of silicon oxide is less than 10 m 2 /g.
在本申请的一些实施方式中，所述硅基材料表面具有金属硫化物。In some embodiments of the present application, the silicon-based material has metal sulfides on the surface.
在本申请的一些实施方式中，所述硅基材料为非多孔结构。In some embodiments of the present application, the silicon-based material has a non-porous structure.
本申请第二方面还提供了前述第一方面提供的负极材料的制备方法，其包括将硅基材料与金属硫化物进行混合。The second aspect of the present application also provides the preparation method of the negative electrode material provided in the foregoing first aspect, which includes mixing a silicon-based material with a metal sulfide.
在本申请的一些实施方式中，其中所述混合通过球磨进行。In some embodiments of the application, wherein the mixing is performed by ball milling.
本申请第三方面还提供了一种负极极片，其包括集流体以及涂覆在所述集流体的至少一个表面上的负极活性物质膜，所述负极活性物质膜包含上述负极材料。The third aspect of the present application also provides a negative pole piece, which includes a current collector and a negative active material film coated on at least one surface of the current collector, the negative active material film comprising the above-mentioned negative electrode material.
本申请第四方面还提供了一种电化学装置，其包含上述负极极片。The fourth aspect of the present application also provides an electrochemical device, which comprises the above-mentioned negative pole piece.
本申请第五方面还提供了一种电子设备，其包含上述电化学装置。The fifth aspect of the present application also provides an electronic device, which includes the electrochemical device described above.
本申请中所用的术语一般为本领域技术人员常用的术语，如果与常用术语不一致，以本申请中的术语为准。The terms used in this application are generally those commonly used by those skilled in the art. If they are inconsistent with the commonly used terms, the terms in this application shall prevail.
本文中，术语“硅碳复合材料”是指由硅和碳复合而成的材料，尤指颗粒状材料。其中硅可以是任意形貌的硅，碳可以是软碳或硬碳或石墨或其组合。复合后的硅碳材料形貌不受限制，可以是多孔的、球型的或无规则颗粒状的。Herein, the term "silicon-carbon composite material" refers to a material composed of silicon and carbon, especially a granular material. The silicon can be silicon with any morphology, and the carbon can be soft carbon or hard carbon or graphite or a combination thereof. The morphology of the composite silicon-carbon material is not limited, and it can be porous, spherical or random granular.
本文中，术语“硅合金”是指由硅与至少一种金属所形成的合金组合物；包括但不限于硅铁合金、硅铝合金、硅镍合金或硅铁铝合金等。Herein, the term "silicon alloy" refers to an alloy composition formed of silicon and at least one metal; including but not limited to silicon-iron alloy, silicon-aluminum alloy, silicon-nickel alloy, or silicon-iron-aluminum alloy.
本文中，术语“硅微米颗粒”是指粒径在微米级的硅颗粒，尤其是指粒径在1-100μm范围内的硅颗粒。Herein, the term "silicon microparticles" refers to silicon particles with a particle size in the micron range, especially silicon particles with a particle size in the range of 1-100 μm.
本文中，术语“硅纳米颗粒”是指粒径在纳米级的硅颗粒，尤其是指粒径在1-1000nm范围内的硅颗粒；Herein, the term "silicon nanoparticle" refers to silicon particles with a particle size in the nanometer range, especially silicon particles with a particle size in the range of 1-1000 nm;
本文中，术语“硅纳米球”是指形貌接近于球型的硅纳米颗粒。Herein, the term "silicon nanosphere" refers to a silicon nanoparticle with a morphology close to a spherical shape.
本文中，术语“硅纳米线”是指具有一维线性结构的硅纳米材料，其线体直径一般在1-1000nm范围内。Here, the term "silicon nanowire" refers to a silicon nanomaterial with a one-dimensional linear structure, and its wire diameter is generally in the range of 1-1000 nm.
本文中，术语“硅纳米薄膜”是指由大量的硅纳米颗粒构成的具有二维平面结构的硅纳米材料。Herein, the term "silicon nano-film" refers to a silicon nanomaterial with a two-dimensional planar structure composed of a large number of silicon nanoparticles.
本文中，术语“D50”表示颗粒累积分布为50％的粒径；即小于此粒径的颗粒体积含量占全部颗粒的50％。所述粒径用激光粒度仪进行测定。Herein, the term "D50" means the particle size at which the cumulative distribution of particles is 50%; that is, the volume content of particles smaller than this size accounts for 50% of all particles. The particle size is measured with a laser particle size analyzer.
本文中，术语“包覆”可以理解为至少部分包覆，也即可以部分包覆，也可以是全部包覆；例如，当描述硅基材料的外表面可以包覆有金属硫化物时，应理解为硅基材料的外表面可以部分包覆有金属硫化物，也可以完全包覆有金属硫化物。In this context, the term "coated" can be understood as at least partially coated, that is, it can be partially coated or fully coated; for example, when it is described that the outer surface of a silicon-based material can be coated with metal sulfide, it should be It is understood that the outer surface of the silicon-based material may be partially covered with metal sulfide or completely covered with metal sulfide.
有益效果Beneficial effect
如前所述，本申请提供的负极材料，通过引入金属硫化物，可以提高负极材料的循环性能。另外，本申请提供的负极材料制备方法，操作简便，易于工业化。此外，本申请提供的负极极片、电化学装置具有良好的循环性能。As mentioned above, the negative electrode material provided by the present application can improve the cycle performance of the negative electrode material by introducing metal sulfide. In addition, the method for preparing the negative electrode material provided in the present application is simple to operate and easy to industrialize. In addition, the negative pole piece and electrochemical device provided by the present application have good cycle performance.
附图说明Description of the drawings
为了更清楚地说明本申请实施例和现有技术的技术方案，下面对实施例和现有技术中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。In order to explain the embodiments of the present application and the technical solutions of the prior art more clearly, the following briefly introduces the drawings that need to be used in the embodiments and the prior art. Obviously, the drawings in the following description are merely the present invention. For some of the embodiments of the application, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.
图1示出实施例3制备的负极材料的SEM图；Figure 1 shows an SEM image of the negative electrode material prepared in Example 3;
图2示出实施例3制备的负极材料中的硅元素的SEM-EDS图；2 shows the SEM-EDS image of silicon in the anode material prepared in Example 3;
图3示出实施例3制备的负极材料中的硫元素的SEM-EDS图；3 shows the SEM-EDS image of sulfur in the anode material prepared in Example 3;
图4示出实施例3制备的负极材料中的锌元素的SEM-EDS图；4 shows a SEM-EDS image of zinc in the anode material prepared in Example 3;
图5示出实施例3和对比例1的嵌锂比容量曲线；Figure 5 shows the specific capacity curves of lithium intercalation in Example 3 and Comparative Example 1;
图6示出实施例3和对比例1的脱锂比容量曲线；Figure 6 shows the specific capacity curves for delithiation of Example 3 and Comparative Example 1;
图7示出实施例3和对比例1的循环容量保持率对比曲线。FIG. 7 shows a comparison curve of the cycle capacity retention rate of Example 3 and Comparative Example 1. FIG.
具体实施方式Detailed ways
以下对本申请的实施方式进行详细说明。The implementation of the present application will be described in detail below.
负极材料Anode material
本申请的负极材料是用于电化学元件制造的负极材料，主要用于锂离子电池、双电层电容器等电化学元件。本申请一个实施方式的负极材料包含硅基材料和金属硫化物；其中，金属硫化物的粒径范围为0.05μm≤D50≤10μm，优选为1μm≤D50≤8μm；更优选为2μm≤D50≤6μm。The negative electrode material of the present application is a negative electrode material used in the manufacture of electrochemical components, and is mainly used in electrochemical components such as lithium ion batteries and electric double layer capacitors. The negative electrode material of one embodiment of the present application includes silicon-based materials and metal sulfides; wherein the particle size range of the metal sulfides is 0.05μm≤D50≤10μm, preferably 1μm≤D50≤8μm; more preferably 2μm≤D50≤6μm .
本申请的发明人发现，通过在硅基材料中引入金属硫化物，可以有效地改善负极材料的循环性能。由于硅基材料在作为负极材料时，嵌锂脱锂过程中的膨胀收缩很大，在充放电过程中导致硅基材料的损坏，从而导致循环性能差。引入金属硫化物后，循环性能明显提高。不限于任何理论，可以认为，在首次嵌锂过程中，金属硫化物与锂离子反应产生金属单质和硫化锂。其中，硫化锂作为缓冲介质可以起到缓解负极嵌锂膨胀的作用；金属元素单质的存在可以增强负极活性膜片的导电性和导离子性，从而改善负极活性膜片的导 电网络，进而改善负极的循环性能。The inventor of the present application found that by introducing metal sulfide into the silicon-based material, the cycle performance of the negative electrode material can be effectively improved. When the silicon-based material is used as a negative electrode material, the expansion and contraction in the process of lithium insertion and removal is very large, which causes damage to the silicon-based material during the charge and discharge process, resulting in poor cycle performance. After the introduction of metal sulfide, the cycle performance is significantly improved. Not limited to any theory, it can be considered that during the first lithium insertion process, metal sulfide reacts with lithium ions to produce elemental metal and lithium sulfide. Among them, lithium sulfide as a buffer medium can play a role in alleviating the expansion of lithium insertion in the negative electrode; the presence of elemental metal elements can enhance the conductivity and ion conductivity of the negative electrode active membrane, thereby improving the conductive network of the negative electrode active membrane, thereby improving the negative electrode Cycle performance.
另外，本申请的发明人发现，当金属硫化物的粒径较大时，负极材料的放电比容量和循环性能会有所降低。而当金属硫化物的粒径过小时，会给负极材料的制备带来困难。In addition, the inventor of the present application found that when the particle size of the metal sulfide is large, the discharge specific capacity and cycle performance of the negative electrode material will be reduced. When the particle size of the metal sulfide is too small, it will bring difficulties to the preparation of the negative electrode material.
在本申请的一些实施方式中，金属硫化物包括硫化锌、硫化铜、硫化亚铜、硫化铁、硫化亚铁、硫化锰、硫化钾、硫化钠、硫化镁、硫化钙、硫化锶、硫化钡或硫化锡中的至少一种。其中，金属硫化物可以单独使用，也可以两种以上组合使用。In some embodiments of the present application, the metal sulfide includes zinc sulfide, copper sulfide, cuprous sulfide, iron sulfide, ferrous sulfide, manganese sulfide, potassium sulfide, sodium sulfide, magnesium sulfide, calcium sulfide, strontium sulfide, barium sulfide Or at least one of tin sulfide. Among them, the metal sulfide may be used alone or in combination of two or more.
本申请的发明人还发现，随着金属硫化物含量增大，首次库伦效率增大，达到峰值后开始减小。以硫化锌为例，当硫化锌含量为5重量％附近时出现该峰值。不限于任何理论，可以认为，这是由于金属硫化物的加入可以在一定程度上减小极化，详见图5和图6，尤其是可以在一定程度上减小脱锂过程中的极化，这在一定程度上可以提升脱锂容量，从而使首次库伦效率提高。The inventor of the present application also found that as the metal sulfide content increases, the first coulombic efficiency increases, and after reaching the peak value, it begins to decrease. Taking zinc sulfide as an example, this peak appears when the zinc sulfide content is around 5 wt%. Not limited to any theory, it can be considered that this is because the addition of metal sulfide can reduce the polarization to a certain extent, as shown in Figure 5 and Figure 6, especially it can reduce the polarization in the delithiation process to a certain extent. , This can increase the delithiation capacity to a certain extent, thereby increasing the first coulombic efficiency.
综合考虑硅负极的循环性能和首次库伦效率，应当控制金属硫化物的含量。在本申请的一些实施方式中，以负极材料的总重量为基准，金属硫化物的含量可以为0.5-12重量％，优选为1-10重量％，更优选为3-8重量％。金属硫化物的含量在上述范围内，电池循环特性明显得到改善。Considering the cycle performance of the silicon anode and the first coulombic efficiency, the content of metal sulfide should be controlled. In some embodiments of the present application, based on the total weight of the negative electrode material, the content of the metal sulfide may be 0.5-12% by weight, preferably 1-10% by weight, more preferably 3-8% by weight. When the content of the metal sulfide is within the above range, the battery cycle characteristics are significantly improved.
在本申请的一些实施方式中，以负极材料的总重量为基准，金属元素的含量可以为0.1-8重量％，优选为2-6重量％。In some embodiments of the present application, based on the total weight of the negative electrode material, the content of the metal element may be 0.1-8 wt%, preferably 2-6 wt%.
在本申请的一些实施方式中，以负极材料的总重量为基准，硫元素的含量可以为0.1-6重量％，优选为1-4重量％。In some embodiments of the present application, based on the total weight of the negative electrode material, the content of sulfur may be 0.1-6 wt%, preferably 1-4 wt%.
通过将金属硫化物含量以及金属元素含量和硫元素含量限定在上述范围内，所得的负极材料能够明显改善电池循环性能，并提高首次库伦效率。By limiting the content of the metal sulfide, the content of the metal element and the content of the sulfur element within the above ranges, the obtained negative electrode material can significantly improve the battery cycle performance and increase the first-time coulombic efficiency.
在本申请的一些实施方式中，硅基材料可以包括硅氧化物、硅、硅碳复合材料或硅合金中的至少一种。这些硅基材料可以单独使用，也可以两种以上组合使用。In some embodiments of the present application, the silicon-based material may include at least one of silicon oxide, silicon, silicon-carbon composite material, or silicon alloy. These silicon-based materials can be used alone or in combination of two or more.
本申请所采用的硅基材料均为本领域已知的材料；可以根据现有技术来 制备或者通过商业途径获得。The silicon-based materials used in this application are all materials known in the art; they can be prepared according to the prior art or obtained through commercial channels.
在本申请的一些实施方式中，所采用的硅基材料优选为非多孔结构。采用非多孔结构的硅基材料，可以提高所制成的负极极片的密度，可以进一步提高结构稳定性，耐受外界较大压力。In some embodiments of the present application, the silicon-based material used is preferably a non-porous structure. The use of non-porous silicon-based materials can increase the density of the produced negative pole piece, further improve the structural stability, and withstand greater external pressure.
在本申请的一些实施方式中，硅氧化物为以SiO x表示的材料，其中0<x<2，优选0.5≤x≤1.6。 In some embodiments of the present application, silicon oxide is a material represented by SiO x , where 0<x<2, preferably 0.5≤x≤1.6.
在本申请的一些实施方式中，硅氧化物表面具有碳材料，硅氧化物可以是用碳部分包覆的或全部包覆的。碳包覆可以提高硅氧化物的导电性，改善其电性能。碳包覆的硅氧化物为本领域已知的材料；可以根据现有技术来制备或者通过商业途径获得。In some embodiments of the present application, the silicon oxide has a carbon material on the surface, and the silicon oxide may be partially or completely coated with carbon. Carbon coating can increase the conductivity of silicon oxide and improve its electrical properties. Carbon-coated silicon oxide is a material known in the art; it can be prepared according to the prior art or obtained through commercial channels.
在本申请的一些实施方式中，硅氧化物的粒径范围优选为1μm≤D50≤10μm。In some embodiments of the present application, the particle size range of the silicon oxide is preferably 1 μm≦D50≦10 μm.
在本申请的一些实施方式中，硅氧化物的比表面积优选小于10m 2/g。 In some embodiments of the present application, the specific surface area of silicon oxide is preferably less than 10 m 2 /g.
此外，硅可以包括硅微米颗粒、硅纳米颗粒、硅纳米线或硅纳米薄膜中的至少一种，这些硅可以单独使用，也可以两种以上组合使用。In addition, silicon may include at least one of silicon microparticles, silicon nanoparticles, silicon nanowires, or silicon nanofilms. These silicons may be used alone or in combination of two or more.
进一步的，硅纳米颗粒可以为硅纳米球。Further, the silicon nanoparticles may be silicon nanospheres.
硅合金可以包括硅铁合金、硅铝合金、硅镍合金或硅铁铝合金中的至少一种。这些硅合金可以单独使用，也可以两种以上组合使用。The silicon alloy may include at least one of silicon-iron alloy, silicon-aluminum alloy, silicon-nickel alloy, or silicon-iron-aluminum alloy. These silicon alloys may be used alone or in combination of two or more kinds.
在本申请的一些实施方式中硅基材料表面具有金属硫化物，部分或全部金属硫化物可以是包覆在硅基材料的至少一部分表面上的。In some embodiments of the present application, the surface of the silicon-based material has metal sulfide, and part or all of the metal sulfide may be coated on at least a part of the surface of the silicon-based material.
在本申请的一些实施方式中，混合物中的硅基材料与金属硫化物处于彼此均匀分散的状态。在本申请的另一些实施方式中，至少部分的硅基材料的外表面可以包覆有金属硫化物；进一步地，不排除硅基材料与包覆的金属硫化物会产生化学反应。In some embodiments of the present application, the silicon-based material and the metal sulfide in the mixture are in a state of being uniformly dispersed with each other. In some other embodiments of the present application, at least part of the outer surface of the silicon-based material may be coated with metal sulfide; further, it is not excluded that the silicon-based material and the coated metal sulfide will have a chemical reaction.
负极材料的制备方法Preparation method of negative electrode material
本申请还提供了上述负极材料的制备方法，包括将硅基材料与金属硫化 物进行混合，得到本申请提供的上述负极材料。This application also provides a method for preparing the above-mentioned negative electrode material, which includes mixing a silicon-based material with a metal sulfide to obtain the above-mentioned negative electrode material provided in this application.
上述制备方法中的混合，可以用本领域技术人员已知的任何方法进行，没有特别限定，只要能将本申请的硅基材料和金属硫化物混合均匀即可，例如各种干法混合或湿法混合。混合可以用本领域技术人员已知的任何混合设备进行，没有特别限定，例如，可以采用球磨机、行星式球磨机、V型混料机、三维混料机、气流混料机或卧式搅拌机等本领域公知的混合设备进行混合。优选采用球磨机或行星式球磨机进行混合。在一些实施方式中，可以先用V型混料机、三维混料机、气流混料机或卧式搅拌机进行干法预混合，然后进行球磨。The mixing in the above preparation method can be carried out by any method known to those skilled in the art, and is not particularly limited, as long as the silicon-based material of the present application and the metal sulfide can be uniformly mixed, such as various dry mixing or wet mixing. Method mixing. The mixing can be carried out by any mixing equipment known to those skilled in the art, and is not particularly limited. For example, a ball mill, a planetary ball mill, a V-shaped mixer, a three-dimensional mixer, an airflow mixer, or a horizontal mixer can be used. Mixing equipment is known in the art for mixing. Preferably, a ball mill or a planetary ball mill is used for mixing. In some embodiments, a V-type mixer, a three-dimensional mixer, an airflow mixer, or a horizontal mixer may be used for dry premixing, and then ball milling.
在发明的一些实施方式中，混合时间没有特别限定，只要可以把本申请的负极材料混合均匀即可。In some embodiments of the invention, the mixing time is not particularly limited, as long as the negative electrode material of the present application can be mixed uniformly.
本申请提供的负极材料的制备方法，简便易行，易于工业化。The preparation method of the negative electrode material provided in this application is simple and easy to implement and easy to industrialize.
负极极片Negative pole piece
本申请提供了一种负极极片，其包括集流体以及涂覆在集流体的至少一个表面上的负极活性物质膜，负极活性物质膜包含本申请提供上述负极材料。The present application provides a negative electrode sheet, which includes a current collector and a negative active material film coated on at least one surface of the current collector, and the negative active material film includes the above-mentioned negative electrode material provided in the present application.
针对集流体没有特别限定，可以采用本领域技术人员公知的任何集流体。具体而言，例如，可以使用由铁、铜、铝、镍、不锈钢、钛、钽、金或铂等形成的集流体。其中，作为负极集流体，特别优选铜箔或铜合金箔。上述材料可以单独使用一种，也可以将两种以上以任意比例组合使用。The current collector is not particularly limited, and any current collector known to those skilled in the art can be used. Specifically, for example, a current collector formed of iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, platinum, or the like can be used. Among them, as the negative electrode current collector, copper foil or copper alloy foil is particularly preferred. The above-mentioned materials may be used singly or in combination of two or more in any ratio.
在本申请的一些实施方式中，负极活性物质膜还可以包含导电剂。针对导电剂没有特别限定，可以是本领域技术人员公知的任何导电剂或其组合，例如，可以采用零维导电剂、一维导电剂及二维导电剂中的至少一种。优选地，导电剂可以包括炭黑、导电石墨、碳纤维、碳纳米管、VGCF(气相法生长碳纤维)或石墨烯中的至少一种。导电剂的用量没有特别限定，可以根据本领域公知常识进行选择。上述导电剂可以单独使用一种，也可以将两种以上以任意比例组合使用。In some embodiments of the present application, the negative active material film may further include a conductive agent. The conductive agent is not particularly limited, and may be any conductive agent or a combination known to those skilled in the art. For example, at least one of a zero-dimensional conductive agent, a one-dimensional conductive agent, and a two-dimensional conductive agent may be used. Preferably, the conductive agent may include at least one of carbon black, conductive graphite, carbon fiber, carbon nanotube, VGCF (Vapour Grown Carbon Fiber) or graphene. The amount of the conductive agent is not particularly limited, and can be selected according to common knowledge in the art. The above-mentioned conductive agent may be used alone or in combination of two or more in any ratio.
在本申请的一些实施方式中，负极活性物质膜还可以包含粘合剂。针对粘合剂没有特别限定，可以是本领域技术人员公知的任何粘合剂或其组合， 例如可以使用聚乙烯醇、羧甲基纤维素、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1,1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂或尼龙等。这些粘合剂可以单独使用一种，也可以将两种以上以任意比例组合使用。In some embodiments of the present application, the negative active material film may further include a binder. The binder is not particularly limited, and it can be any binder or combination known to those skilled in the art. For example, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, and polyvinyl cellulose can be used. Vinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, Styrene butadiene rubber, acrylic (ester) styrene butadiene rubber, epoxy resin or nylon, etc. These binders may be used alone or in combination of two or more in any ratio.
负极极片的制备Preparation of negative pole piece
负极极片的制备对于本领域技术人员来说是熟知的；在本申请中，负极极片的制备过程包括：将本申请提供的负极材料、导电剂和粘结剂按一定的质量比分散于溶剂中充分搅拌混合均匀后，涂覆于集流体上，经过烘干、冷压，得到负极极片。所采用的溶剂没有特别的限定，例如，可以采用N-甲基吡咯烷酮，丙酮或水等。这些溶剂可以单独使用一种，也可以将两种以上以任意比例组合使用。The preparation of the negative pole piece is well known to those skilled in the art; in this application, the preparation process of the negative pole piece includes: dispersing the negative electrode material, conductive agent and binder provided in this application in a certain mass ratio After the solvent is fully stirred and mixed uniformly, it is coated on the current collector, dried, and cold pressed to obtain a negative pole piece. The solvent used is not particularly limited. For example, N-methylpyrrolidone, acetone or water can be used. These solvents may be used alone or in combination of two or more in any ratio.
电化学装置Electrochemical device
本申请的电化学装置包括但不限于：所有种类的一次电池、二次电池、燃料电池、太阳能电池或电容。一种典型的电化学装置就是锂离子电池，其是一种二次电池。电化学装置，例如锂离子电池一般包含有负极极片、正极极片、隔膜及电解液。The electrochemical device of the present application includes, but is not limited to: all kinds of primary batteries, secondary batteries, fuel cells, solar cells or capacitors. A typical electrochemical device is a lithium ion battery, which is a secondary battery. Electrochemical devices, such as lithium-ion batteries, generally include a negative pole piece, a positive pole piece, a separator, and an electrolyte.
本申请提供的电化学装置，其负极极片采用本申请提供的负极极片；而其它的组成部分，包括正极极片、隔膜及电解液等，没有特别的限定。示例性地，正极极片所包含的正极材料可以包括但不限于钴酸锂、锰酸锂、磷酸铁锂等。隔膜的材质可以包括但不限于玻璃纤维、聚酯、聚乙烯、聚丙烯、聚四氟乙烯或其组合。电解液一般包括有机溶剂、锂盐和添加剂。有机溶剂可以包括但不限于碳酸亚乙酯、碳酸亚乙烯酯、碳酸亚丙酯、碳酸二乙酯、碳酸甲乙酯、碳酸二甲酯或丙酸乙酯中的至少一种。锂盐可以包括有机锂盐或无机锂盐中的至少一种。具体地，锂盐可以包括六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、二氟磷酸锂(LiPO 2F 2)、双三氟甲烷磺酰亚胺锂LiN(CF 3SO 2) 2(LiTFSI)、双(氟磺酰)亚胺锂Li(N(SO 2F) 2)(LiFSI)、双草酸硼酸锂LiB(C 2O 4) 2(LiBOB)或二氟草酸硼酸锂LiBF 2(C 2O 4)(LiDFOB)中的至少一种。 In the electrochemical device provided in this application, the negative pole piece of the electrochemical device provided in this application adopts the negative pole piece provided in this application; and other components, including the positive pole piece, separator, electrolyte, etc., are not particularly limited. Exemplarily, the positive electrode material contained in the positive pole piece may include, but is not limited to, lithium cobaltate, lithium manganate, lithium iron phosphate, and the like. The material of the diaphragm may include, but is not limited to, glass fiber, polyester, polyethylene, polypropylene, polytetrafluoroethylene, or a combination thereof. The electrolyte generally includes organic solvents, lithium salts and additives. The organic solvent may include, but is not limited to, at least one of ethylene carbonate, vinylene carbonate, propylene carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl carbonate, or ethyl propionate. The lithium salt may include at least one of an organic lithium salt or an inorganic lithium salt. Specifically, the lithium salt may include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium bistrifluoromethanesulfonimide LiN (CF 3 SO 2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), lithium bisoxalate borate LiB(C 2 O 4 ) 2 (LiBOB) or lithium difluorooxalate LiBF 2 At least one of (C 2 O 4 ) (LiDFOB).
电化学装置的制备过程为本领域技术人员所熟识的，本申请没有特别的限定。例如二次电池可以通过以下过程制造：将正极和负极经由间隔件重叠，并根据需要将其卷绕、折叠等操作后放入电池容器，将电解液注入电池容器并封口，其中所用的负极为本申请提供的上述负极极片。此外，也可以根据需要将防过电流元件、导板等置于电池容器中，从而防止电池内部的压力上升、过充放电。The preparation process of the electrochemical device is familiar to those skilled in the art, and this application is not particularly limited. For example, a secondary battery can be manufactured by the following process: overlap the positive electrode and the negative electrode via spacers, and place them in the battery container after winding, folding and other operations as needed, and inject the electrolyte into the battery container and seal it. The negative electrode used is The above-mentioned negative pole piece provided in this application. In addition, an overcurrent prevention element, a guide plate, etc. can also be placed in the battery container as needed, so as to prevent the internal pressure of the battery from rising and overcharging and discharging.
本申请还提供了一种电子设备，其包含本申请提供的电化学装置。The application also provides an electronic device, which includes the electrochemical device provided in the application.
进一步，电化学装置可以是本申请提供的锂离子电池。Further, the electrochemical device may be a lithium ion battery provided in the present application.
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.
实施例1Example 1
原料raw material
实施例中所使用的SiOx(x＝0.8)，D50为6μm,比表面积为2m 2/g。 The SiOx (x=0.8) used in the examples has a D50 of 6 μm and a specific surface area of 2 m 2 /g.
实施例中所用的金属硫化物的D50为3μm。The D50 of the metal sulfide used in the examples is 3 μm.
负极材料的制备Preparation of anode material
将99重量份的SiO x与1重量份的硫化锌加入到行星式球磨机中球磨6小时，得到负极材料。 99 parts by weight of SiO x and 1 part by weight of zinc sulfide were added to a planetary ball mill and ball milled for 6 hours to obtain a negative electrode material.
负极极片的制备Preparation of negative pole piece
将负极材料：导电剂SuperP:羧甲基纤维素按8:1:1的重量比混合，加入水并混合作为分散介质，得到固相含量为40％的负极浆料。然后将上述负极浆料涂覆涂布在10μm的铜集流体上，使干燥后的膜厚为38μm；然后在110℃下烘干；然后使用辊式压制机压延，得到负极活性物质膜厚度为30μm负极极片。The negative electrode material: the conductive agent SuperP: carboxymethyl cellulose is mixed in a weight ratio of 8:1:1, and water is added and mixed as a dispersion medium to obtain a negative electrode slurry with a solid content of 40%. Then, the above-mentioned negative electrode slurry was coated on a 10μm copper current collector so that the film thickness after drying was 38μm; then it was dried at 110°C; then it was calendered using a roller press to obtain a negative electrode active material film thickness of 30μm negative pole piece.
半电池的组装Half-cell assembly
以金属锂作为对电极进行扣式半电池组装。The button half-cell assembly is carried out with metallic lithium as the counter electrode.
将锂盐LiPF 6与非水有机溶剂按重量比8：92配制而成的溶液作为锂离子电池的电解液，其中，非水有机溶剂是重量比为碳酸亚乙酯(EC)：碳酸二乙酯(DEC)：碳酸亚丙酯(PC)：丙酸丙酯(PP)：碳酸亚乙烯酯(VC)＝20:30:20:28:2的混合物。 A solution prepared by lithium salt LiPF 6 and non-aqueous organic solvent at a weight ratio of 8:92 is used as the electrolyte for lithium-ion batteries, where the non-aqueous organic solvent is ethylene carbonate (EC): diethyl carbonate in weight ratio Ester (DEC): propylene carbonate (PC): propyl propionate (PP): vinylene carbonate (VC) = a mixture of 20:30:20:28:2.
隔离膜采用陶瓷涂覆的聚乙烯(PE)材料隔离膜。The isolation membrane adopts a ceramic-coated polyethylene (PE) material isolation membrane.
将锂片、隔离膜、负极极片按顺序叠好，使隔离膜处于正负极中间起到隔离的作用。将电极组件置于包装壳中，注入电解液并封装。对组装后的电池进行化成，然后充放电实验。Lay the lithium sheet, the separator film, and the negative pole piece in order, so that the separator is in the middle of the positive and negative electrodes to play a role of isolation. Place the electrode assembly in the packaging case, inject electrolyte and package. The assembled battery is formed, and then charged and discharged.
充放电比容量测试Charge and discharge specific capacity test
以0.05C的倍率恒流放电至5mV，静止5分钟后，改为50uA的电流继续放电至5mV，再静止5分钟后，改用10uA的电流继续放电至5mV；再以0.05C的倍率恒流充电至2V，静止30分钟后即完成充放电比容量测试。结果列于表1。Discharge to 5mV at a constant current rate of 0.05C. After standing for 5 minutes, change to a current of 50uA and continue to discharge to 5mV. After standing still for 5 minutes, switch to a current of 10uA and continue to discharge to 5mV; then use a constant current of 0.05C. Charge to 2V and complete the charge-discharge specific capacity test after 30 minutes of inactivity. The results are shown in Table 1.
首次库伦效率First coulomb efficiency
首次库伦效率＝首次放电比容量/首次充电比容量。First Coulomb efficiency = first discharge specific capacity/first charge specific capacity.
循环测试Loop test
以0.05C的倍率恒流放电至5mV，静止5分钟后，改为50uA的电流继续放电至5mV，再静止5分钟后，改用10uA的电流继续放电至5mV；再以0.05C的倍率恒流充电至2V，静止30分钟后即完成1个充放电循环。重复进行上述充放电循环测试以测试锂离子电池的循环性能。表1列出了经过15个充放电循环后的容量保持率。Discharge to 5mV at a constant current rate of 0.05C. After standing for 5 minutes, change to a current of 50uA and continue to discharge to 5mV. After standing still for 5 minutes, switch to a current of 10uA and continue to discharge to 5mV; then use a constant current of 0.05C. Charge to 2V and complete a charge-discharge cycle after 30 minutes of inactivity. The above-mentioned charge-discharge cycle test was repeated to test the cycle performance of the lithium ion battery. Table 1 lists the capacity retention rate after 15 charge-discharge cycles.
实施例2Example 2
将实施例1中的材料比例变成97重量份SiO x和3重量份硫化锌，其余与实施例1相同。 The material ratio in Example 1 is changed to 97 parts by weight of SiO x and 3 parts by weight of zinc sulfide, and the rest is the same as in Example 1.
实施例3Example 3
将实施例1中的材料比例变成95重量份SiO x和5重量份硫化锌，其余与实施例1相同。 The material ratio in Example 1 is changed to 95 parts by weight of SiO x and 5 parts by weight of zinc sulfide, and the rest is the same as in Example 1.
图1示出了实施例3的负极材料的扫描电子显微镜照片，图2-4分别示出了图1区域中的硅元素、硫元素和锌元素的扫描电子显微镜能谱图。从图2-4中可以看出，硅基材料和硫化锌形成了均匀混合的材料。Fig. 1 shows a scanning electron micrograph of the negative electrode material of Example 3, and Figs. 2-4 show the scanning electron microscope energy spectra of the silicon element, the sulfur element and the zinc element in the area of Fig. 1 respectively. It can be seen from Figure 2-4 that the silicon-based material and zinc sulfide form a uniformly mixed material.
实施例4Example 4
将实施例1中的材料比例变成92重量份SiO x和8重量份硫化锌，其余与实施例1相同。 The material ratio in Example 1 is changed to 92 parts by weight of SiO x and 8 parts by weight of zinc sulfide, and the rest is the same as in Example 1.
实施例5Example 5
将实施例1中的材料比例变成90重量份SiO x和10重量份硫化锌，其余与实施例1相同。 The material ratio in Example 1 is changed to 90 parts by weight of SiO x and 10 parts by weight of zinc sulfide, and the rest is the same as in Example 1.
实施例6Example 6
将99重量份SiO x与1重量份硫化锌置于搅拌罐中干混1小时，得到负极材料。然后按负极材料：导电剂SuperP：粘结剂羧甲基纤维素为8：1：1的比例称量配料，加水混合得到负极浆料，其固体含量为40重量％。将上述负极浆料涂覆在铜集流体上，进行烘干并进行滚压，得到负极极片。与金属锂作为对电极进行扣式半电池组装，对组装后的电池进行充放电实验；其余与实施例1相同。 99 parts by weight of SiO x and 1 part by weight of zinc sulfide were dry-mixed in a stirring tank for 1 hour to obtain a negative electrode material. Then, the ingredients are weighed according to the ratio of the negative electrode material: the conductive agent SuperP: the binder carboxymethyl cellulose of 8:1:1, and water is added to mix to obtain the negative electrode slurry, the solid content of which is 40% by weight. The above-mentioned negative electrode slurry is coated on a copper current collector, dried and rolled to obtain a negative electrode piece. The button half-cell assembly was carried out with lithium metal as the counter electrode, and the charge and discharge experiment was carried out on the assembled battery; the rest was the same as in Example 1.
实施例7Example 7
将实施例6中的材料比例变成95重量份SiO x和5重量份硫化锌，其余与实施例6相同。 The material ratio in Example 6 is changed to 95 parts by weight of SiO x and 5 parts by weight of zinc sulfide, and the rest is the same as in Example 6.
实施例8Example 8
将实施例6中的材料比例变成90重量份SiO x和10重量份硫化锌，其余与实施例6相同。 The material ratio in Example 6 is changed to 90 parts by weight of SiO x and 10 parts by weight of zinc sulfide, and the rest is the same as in Example 6.
实施例9Example 9
将实施例3中的硫化锌替换为D50为3μm的硫化铜，其余与实施例3相同。The zinc sulfide in Example 3 is replaced with copper sulfide with a D50 of 3 μm, and the rest is the same as in Example 3.
实施例10Example 10
将实施例3中的硫化锌替换为D50为3μm的硫化铁，其余与实施例3相同。The zinc sulfide in Example 3 was replaced with iron sulfide with a D50 of 3 μm, and the rest was the same as in Example 3.
实施例11Example 11
将实施例3中的硫化锌替换为1:1的D50均为3μm的硫化锌和硫化铜，其余与实施例3相同。Replace the zinc sulfide in Example 3 with 1:1 zinc sulfide and copper sulfide whose D50 is 3 μm, and the rest is the same as in Example 3.
实施例12Example 12
将实施例1中的硅材料更换为硅微米颗粒，D50为4μm,比表面积为3m2/g，其余与实施例1相同。The silicon material in Example 1 is replaced with silicon micron particles, the D50 is 4 μm, the specific surface area is 3 m2/g, and the rest is the same as in Example 1.
实施例13Example 13
将实施例12中的材料比例变成97重量份硅微米颗粒和3重量份硫化锌，其余与实施例12相同。The material ratio in Example 12 is changed to 97 parts by weight of silicon micron particles and 3 parts by weight of zinc sulfide, and the rest is the same as in Example 12.
实施例14Example 14
将实施例12中的材料比例变成95重量份硅微米颗粒和5重量份硫化锌，其余与实施例12相同。The material ratio in Example 12 is changed to 95 parts by weight of silicon micron particles and 5 parts by weight of zinc sulfide, and the rest is the same as in Example 12.
实施例15Example 15
将实施例3中的硫化锌更换为D50为0.5μm的硫化锌，其余与实施例3相同。The zinc sulfide in Example 3 was replaced with zinc sulfide with a D50 of 0.5 μm, and the rest was the same as in Example 3.
实施例16Example 16
将实施例3中的硫化锌更换为D50为6μm的硫化锌，其余与实施例3相同。The zinc sulfide in Example 3 was replaced with zinc sulfide with a D50 of 6 μm, and the rest was the same as in Example 3.
实施例17Example 17
将实施例3中的硫化锌更换为D50为10μm的硫化锌，其余与实施例3相同。The zinc sulfide in Example 3 was replaced with zinc sulfide with a D50 of 10 μm, and the rest was the same as in Example 3.
对比例1Comparative example 1
直接使用SiO X作为负极材料，不进行球磨，其余与实施例1相同。 SiO X was used directly as the negative electrode material without ball milling, and the rest was the same as in Example 1.
对比例2Comparative example 2
直接使用SiO X作为负极材料，并且如实施例1所述进行球磨处理，其余与实施例1相同。 SiO X was directly used as the negative electrode material, and the ball milling treatment was performed as described in Example 1, and the rest was the same as in Example 1.
对比例3Comparative example 3
直接使用硅微米颗粒作为负极材料，不进行球磨，其余与实施例1相同。The silicon micron particles were directly used as the negative electrode material without ball milling, and the rest was the same as in Example 1.
对比例4Comparative example 4
直接使用硅微米颗粒作为负极材料，并且如实施例1所述进行球磨处理，其余与实施例1相同。The silicon micron particles were directly used as the negative electrode material, and the ball milling process was performed as described in Example 1, and the rest was the same as in Example 1.
表1-4列出了各实施例和比较例的成分以及放电比容量、首次库伦效率和容量保持率。Table 1-4 lists the components, discharge specific capacity, first coulombic efficiency and capacity retention rate of each embodiment and comparative example.
表1Table 1
Figure PCTCN2019124830-appb-000001
Figure PCTCN2019124830-appb-000001
表2Table 2
Figure PCTCN2019124830-appb-000002
Figure PCTCN2019124830-appb-000002
表3table 3
Figure PCTCN2019124830-appb-000003
Figure PCTCN2019124830-appb-000003
表4Table 4
Figure PCTCN2019124830-appb-000004
Figure PCTCN2019124830-appb-000004
从表1可以看出，在实施例1～5中，随着硫化锌含量增大，放电比容量依次降低，并且都低于对比例1和对比例2；首次库伦效率先增大，在硫化锌含量达到5％时最大，然后逐渐降低；与对比例1和对比例2相比，实施例1～5的负极材料的容量保持率显著提高。It can be seen from Table 1 that in Examples 1 to 5, as the zinc sulfide content increases, the discharge specific capacity decreases successively, and both are lower than Comparative Example 1 and Comparative Example 2. The first coulombic efficiency increases first, and after the vulcanization The zinc content reaches the maximum when it reaches 5%, and then gradually decreases; compared with Comparative Example 1 and Comparative Example 2, the capacity retention rate of the negative electrode materials of Examples 1 to 5 is significantly improved.
图5示出实施例3和对比例1的嵌锂比容量曲线。从图5可以看出，与对比例1相比，实施例3的初始嵌锂电位高，说明实施例3的嵌锂极化小于对比例1。FIG. 5 shows the lithium intercalation specific capacity curves of Example 3 and Comparative Example 1. It can be seen from FIG. 5 that compared with Comparative Example 1, the initial lithium insertion potential of Example 3 is higher, indicating that the lithium insertion polarization of Example 3 is lower than that of Comparative Example 1.
图6示出实施例3和对比例1的脱锂比容量曲线；从图6可以看出，与对比例1相比，实施例3脱锂静止后的电压降小，说明实施例3的脱锂极化小于对比例1。可见，硫化锌在嵌锂过程中形成的金属锌增加了极片整体的导电性，从而可以在一定程度上减小负极材料的极化，尤其是在一定程度上减小脱锂过程中负极材料的极化，这在一定程度上可以提升脱锂容量，从而使首次库伦效率提高。Figure 6 shows the delithiation specific capacity curves of Example 3 and Comparative Example 1. It can be seen from Figure 6 that, compared with Comparative Example 1, the voltage drop after delithiation in Example 3 is small, indicating the delithiation of Example 3 The lithium polarization is smaller than that of Comparative Example 1. It can be seen that the metallic zinc formed during the lithium insertion process of zinc sulfide increases the overall conductivity of the pole piece, which can reduce the polarization of the negative electrode material to a certain extent, especially to reduce the negative electrode material in the lithium removal process to a certain extent. Polarization, which can increase the delithiation capacity to a certain extent, thereby increasing the first coulombic efficiency.
图7示出使用实施例3和对比例1的循环容量保持率。从图7可以看出， 硫化锌的引入可以显著地改善硅基负极材料的循环性。不限于任何理论，可以认为，硫化锌嵌锂过程中形成的硫化锂可以作为缓冲相减缓硅的嵌锂膨胀。硫化锌的引入带来了良好的导电网络(金属锌)及缓冲相，从而可以显著地改善负极极片的循环性能。FIG. 7 shows the cycle capacity retention rate using Example 3 and Comparative Example 1. FIG. It can be seen from Figure 7 that the introduction of zinc sulfide can significantly improve the cycleability of the silicon-based negative electrode material. Without being limited to any theory, it can be considered that the lithium sulfide formed during the lithium intercalation process of zinc sulfide can serve as a buffer phase to slow down the lithium intercalation expansion of silicon. The introduction of zinc sulfide brings a good conductive network (metallic zinc) and buffer phase, which can significantly improve the cycle performance of the negative pole piece.
从表1还可以看出，实施例6，7，8具有相同的放电比容量和首次库伦效率变化规律。但是，仅经过干混，而没有经过球磨处理的实施例6、7、8的循环性能明显低于经过球磨处理的实施例1-5。不限于任何理论，可以认为，球磨处理会导致材料表面状态的改变，硅基材料外表面的至少一部分被硫化锌包覆，或者在球磨过程中，在机械力的作用下，硅基材料与硫化锌发生某种程度的化学反应，使得硅基材料颗粒的表面结构更加稳定，进一步提高了硅基负极材料的循环性能。It can also be seen from Table 1 that Examples 6, 7, and 8 have the same discharge specific capacity and first-time coulombic efficiency change law. However, the cycle performance of Examples 6, 7, and 8 that were only subjected to dry mixing without ball milling treatment was significantly lower than that of Examples 1-5 that were subjected to ball milling treatment. Not limited to any theory, it can be considered that the ball milling treatment will cause the change of the surface state of the material. At least a part of the outer surface of the silicon-based material is coated with zinc sulfide, or during the ball milling process, under the action of mechanical force, the silicon-based material and the vulcanization A certain degree of chemical reaction of zinc makes the surface structure of the silicon-based material particles more stable, and further improves the cycle performance of the silicon-based anode material.
从表2的实施例9，10，11还可以看出，与硫化锌类似，硫化铜或硫化铁或硫化锌与硫化铜的组合都能够明显提高硅基负极材料的循环性能。It can also be seen from Examples 9, 10, and 11 in Table 2 that, similar to zinc sulfide, copper sulfide or iron sulfide or the combination of zinc sulfide and copper sulfide can significantly improve the cycle performance of the silicon-based anode material.
从表3的实施例12，13，14还可以看出，与SiOx类似，硅材料更换为硅微米颗粒，硫化锌也能明显提高其作为负极材料的循环性能。It can also be seen from Examples 12, 13, and 14 in Table 3 that, similar to SiOx, the silicon material is replaced with silicon micron particles, and zinc sulfide can also significantly improve its cycle performance as a negative electrode material.
从表4的实施例3，16，17还可以看出，当增大所使用硫化锌的粒径(D50)时，放电比容量和循环性能都有所降低，这是由于硫化锌的颗粒过大会导致其对硅颗粒的表面附着能力变差，从而不能充分起到表面键合作用。而当所使用硫化锌的平均粒径较小时(如实施例15)，材料的性能变化不明显，说明继续减小硫化锌的粒径不能持续带来性能的进一步提升，反而可能会由于颗粒过小带来操作上的困难，颗粒过小会发生自身团聚。It can also be seen from Examples 3, 16, and 17 in Table 4 that when the particle size (D50) of the zinc sulfide used is increased, the specific discharge capacity and cycle performance are reduced. This is due to excessive zinc sulfide particles. As a result, its ability to adhere to the surface of silicon particles deteriorates, so that the surface bonding effect cannot be fully achieved. When the average particle size of zinc sulfide used is small (as in Example 15), the performance of the material does not change significantly, indicating that continuing to reduce the particle size of zinc sulfide cannot continue to bring further improvement in performance, but may be due to too small particles Bringing operational difficulties, particles that are too small will reunite themselves.
上述实施例的作用在于说明本申请的实质性内容，但并不以此限定本申请的保护范围。本领域的普通技术人员应当理解，可以对本申请的技术方案进行修改或者等同替换，而不脱离本申请技术方案的实质和保护范围。The function of the foregoing embodiments is to illustrate the substantive content of the application, but does not limit the scope of protection of the application. Those of ordinary skill in the art should understand that the technical solution of the present application can be modified or equivalently replaced without departing from the essence and protection scope of the technical solution of the present application.

Claims (10)

  1. 一种负极材料，其包含硅基材料和金属硫化物；其中，所述金属硫化物的粒径范围为0.05μm≤D50≤10μm。A negative electrode material comprising a silicon-based material and a metal sulfide; wherein the particle size range of the metal sulfide is 0.05 μm≦D50≦10 μm.
  2. 根据权利要求1所述的负极材料，其中，所述金属硫化物满足如下至少一项特征：The negative electrode material according to claim 1, wherein the metal sulfide satisfies at least one of the following characteristics:
    所述金属硫化物包括硫化锌、硫化铜、硫化亚铜、硫化铁、硫化亚铁、硫化锰、硫化钾、硫化钠、硫化镁、硫化钙、硫化锶、硫化钡或硫化锡中的至少一种；The metal sulfide includes at least one of zinc sulfide, copper sulfide, cuprous sulfide, iron sulfide, ferrous sulfide, manganese sulfide, potassium sulfide, sodium sulfide, magnesium sulfide, calcium sulfide, strontium sulfide, barium sulfide, or tin sulfide Species
    以所述负极材料的总重量为基准，所述金属硫化物的含量为0.5-12重量％；Based on the total weight of the negative electrode material, the content of the metal sulfide is 0.5-12% by weight;
    以所述负极材料的总重量为基准，金属元素的含量为0.1-8重量％；Based on the total weight of the negative electrode material, the content of the metal element is 0.1-8% by weight;
    以所述负极材料的总重量为基准，硫元素的含量为0.1-6重量％。Based on the total weight of the negative electrode material, the content of sulfur element is 0.1 to 6% by weight.
  3. 根据权利要求1所述的负极材料，其中，所述硅基材料包括硅氧化物、硅、硅碳复合材料或硅合金中的至少一种。The anode material according to claim 1, wherein the silicon-based material includes at least one of silicon oxide, silicon, silicon-carbon composite material, or silicon alloy.
  4. 根据权利要求3所述的负极材料，其中，所述硅基材料满足如下至少一项特征：The anode material according to claim 3, wherein the silicon-based material satisfies at least one of the following characteristics:
    所述硅氧化物表面具有含碳材料；The surface of the silicon oxide has a carbon-containing material;
    所述硅氧化物的粒径范围为1μm≤D50≤10μm；比表面积小于10m 2/g； The particle size range of the silicon oxide is 1μm≤D50≤10μm; the specific surface area is less than 10m 2 /g;
    所述硅包括硅微米颗粒、硅纳米颗粒、硅纳米线或硅纳米薄膜中的至少一种；The silicon includes at least one of silicon micro-particles, silicon nanoparticles, silicon nanowires, or silicon nano-films;
    所述硅合金包括硅铁合金、硅铝合金、硅镍合金或硅铁铝合金中的至少一种。The silicon alloy includes at least one of silicon-iron alloy, silicon-aluminum alloy, silicon-nickel alloy, or silicon-iron-aluminum alloy.
  5. 根据权利要求3所述的负极材料，其中，所述硅基材料为硅氧化物SiO x，其中，0<x<2。 The negative electrode material according to claim 3, wherein said silicon-based material is a silicon oxide SiO x, where, 0 <x <2.
  6. 根据权利要求1所述的负极材料，其中，所述硅基材料表面具有金属硫化物。The negative electrode material according to claim 1, wherein the silicon-based material has a metal sulfide on the surface.
  7. 权利要求1-6中任一项所述的负极材料的制备方法，其包括将硅基材料与金属硫化物进行混合。The method for preparing a negative electrode material according to any one of claims 1 to 6, which comprises mixing a silicon-based material with a metal sulfide.
  8. 一种负极极片，其包含集流体和涂覆在所述集流体的至少一个表面上的负极活性物质膜；所述负极活性物质膜包含权利要求1-6中任一项所述的负极材料。A negative pole piece comprising a current collector and a negative active material film coated on at least one surface of the current collector; the negative active material film comprises the negative electrode material according to any one of claims 1-6 .
  9. 一种电化学装置，其包含权利要求8所述的负极极片。An electrochemical device comprising the negative pole piece of claim 8.
  10. 一种电子设备，其包含权利要求9所述的电化学装置。An electronic device comprising the electrochemical device according to claim 9.
PCT/CN2019/124830 2019-12-12 2019-12-12 Negative electrode material, preparation method therefor, negative electrode piece, and electrochemical apparatus WO2021114172A1 (en)

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CN102412394A (en) * 2011-10-20 2012-04-11 浙江大学 Preparation method of lamellar stannic sulfide/silicon oxide nuclear shell nanorod for lithium battery
CN107240688A (en) * 2017-06-15 2017-10-10 山东大学 A kind of silicium cathode material of sulfenyl solid electrolyte cladding and preparation method thereof
CN108963204A (en) * 2018-06-11 2018-12-07 华南师范大学 Silicon substrate/sulfide cathode material preparation method of one type graphene interlayers structure
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102412394A (en) * 2011-10-20 2012-04-11 浙江大学 Preparation method of lamellar stannic sulfide/silicon oxide nuclear shell nanorod for lithium battery
CN107240688A (en) * 2017-06-15 2017-10-10 山东大学 A kind of silicium cathode material of sulfenyl solid electrolyte cladding and preparation method thereof
CN109560247A (en) * 2017-09-26 2019-04-02 宁德新能源科技有限公司 Lithium ion battery and its cathode pole piece
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