CN118588943A - All-solid-state composite negative electrode plate and all-solid-state battery - Google Patents
All-solid-state composite negative electrode plate and all-solid-state battery Download PDFInfo
- Publication number
- CN118588943A CN118588943A CN202411075289.3A CN202411075289A CN118588943A CN 118588943 A CN118588943 A CN 118588943A CN 202411075289 A CN202411075289 A CN 202411075289A CN 118588943 A CN118588943 A CN 118588943A
- Authority
- CN
- China
- Prior art keywords
- solid
- negative electrode
- composite negative
- state
- fibrous
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002131 composite material Substances 0.000 title claims abstract description 119
- 239000005038 ethylene vinyl acetate Substances 0.000 claims abstract description 114
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims abstract description 114
- 239000007784 solid electrolyte Substances 0.000 claims abstract description 60
- 239000011230 binding agent Substances 0.000 claims abstract description 52
- 239000006258 conductive agent Substances 0.000 claims abstract description 42
- 239000007787 solid Substances 0.000 claims abstract description 32
- 239000007773 negative electrode material Substances 0.000 claims abstract description 29
- 239000002245 particle Substances 0.000 claims description 50
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 28
- 239000006183 anode active material Substances 0.000 claims description 28
- 239000002134 carbon nanofiber Substances 0.000 claims description 26
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 claims description 22
- 229910002804 graphite Inorganic materials 0.000 claims description 21
- 239000010439 graphite Substances 0.000 claims description 21
- 239000000835 fiber Substances 0.000 claims description 20
- 238000002844 melting Methods 0.000 claims description 18
- 230000008018 melting Effects 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 16
- 239000002210 silicon-based material Substances 0.000 claims description 10
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical class C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 9
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 8
- 239000004917 carbon fiber Substances 0.000 claims description 8
- 238000009825 accumulation Methods 0.000 claims description 6
- 239000000853 adhesive Substances 0.000 claims description 6
- 230000001070 adhesive effect Effects 0.000 claims description 6
- 150000004820 halides Chemical class 0.000 claims description 5
- 239000002203 sulfidic glass Substances 0.000 claims description 5
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 4
- 229910021383 artificial graphite Inorganic materials 0.000 claims description 4
- 239000002041 carbon nanotube Substances 0.000 claims description 4
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 4
- 229910021419 crystalline silicon Inorganic materials 0.000 claims description 4
- 229910021382 natural graphite Inorganic materials 0.000 claims description 4
- 239000006250 one-dimensional material Substances 0.000 claims description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 claims description 2
- 239000010703 silicon Substances 0.000 claims description 2
- 238000000034 method Methods 0.000 abstract description 18
- 230000008859 change Effects 0.000 abstract description 17
- 230000008569 process Effects 0.000 abstract description 12
- 239000006182 cathode active material Substances 0.000 abstract description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 35
- 229910001416 lithium ion Inorganic materials 0.000 description 35
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 30
- 238000002360 preparation method Methods 0.000 description 29
- 238000000498 ball milling Methods 0.000 description 28
- 230000000052 comparative effect Effects 0.000 description 28
- 229910010848 Li6PS5Cl Inorganic materials 0.000 description 24
- 238000002156 mixing Methods 0.000 description 15
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 13
- 239000004810 polytetrafluoroethylene Substances 0.000 description 13
- 239000003792 electrolyte Substances 0.000 description 10
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 7
- 239000005977 Ethylene Substances 0.000 description 7
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 6
- 239000011324 bead Substances 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 6
- 229910052726 zirconium Inorganic materials 0.000 description 6
- 239000010405 anode material Substances 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000002033 PVDF binder Substances 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229920005596 polymer binder Polymers 0.000 description 4
- 239000002491 polymer binding agent Substances 0.000 description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 229910000846 In alloy Inorganic materials 0.000 description 3
- -1 Polytetrafluoroethylene Polymers 0.000 description 3
- NPYPAHLBTDXSSS-UHFFFAOYSA-N Potassium ion Chemical compound [K+] NPYPAHLBTDXSSS-UHFFFAOYSA-N 0.000 description 3
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 239000011888 foil Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- LHJOPRPDWDXEIY-UHFFFAOYSA-N indium lithium Chemical group [Li].[In] LHJOPRPDWDXEIY-UHFFFAOYSA-N 0.000 description 3
- 230000037427 ion transport Effects 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- 229910001414 potassium ion Inorganic materials 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 230000002441 reversible effect Effects 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 229910001415 sodium ion Inorganic materials 0.000 description 3
- 230000008093 supporting effect Effects 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 229910018540 Si C Inorganic materials 0.000 description 2
- 239000012300 argon atmosphere Substances 0.000 description 2
- 239000007767 bonding agent Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000000713 high-energy ball milling Methods 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- KZKGLGIVGQYOTG-UHFFFAOYSA-N [F].[Au] Chemical compound [F].[Au] KZKGLGIVGQYOTG-UHFFFAOYSA-N 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 239000002706 dry binder Substances 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- 239000011244 liquid electrolyte Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
- 229920000428 triblock copolymer Polymers 0.000 description 1
Classifications
-
- 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
Landscapes
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The application provides an all-solid-state composite negative electrode piece and an all-solid-state battery, wherein the all-solid-state composite negative electrode piece comprises: the cathode active material, the solid electrolyte, the conductive agent and the binder, wherein the binder is fibrous ethylene-vinyl acetate copolymer, and the mass ratio of the fibrous ethylene-vinyl acetate copolymer to the all-solid composite cathode pole piece is 3-15: 70-115, wherein the fibrous ethylene-vinyl acetate copolymer forms a three-dimensional crosslinked network inside the all-solid-state composite negative electrode plate. The all-solid-state composite negative electrode plate provided by the application utilizes the fibrous ethylene-vinyl acetate copolymer to relieve the volume change of the negative electrode active material of the all-solid-state composite negative electrode plate in the charge and discharge process, and enhances the interface contact of all components in the all-solid-state composite negative electrode plate, thereby improving the cycle performance of the all-solid-state battery.
Description
Technical Field
The application relates to the field of batteries, in particular to an all-solid-state composite negative electrode plate and an all-solid-state battery.
Background
In the rapid development of new energy fields, battery development such as lithium ion batteries is particularly important, and all-solid-state batteries are regarded as one of the final forms of commercial lithium ion batteries, and by replacing flammable liquid electrolytes with solid electrolytes, it is possible to provide users with safer next-generation power batteries having higher energy density and better long-term cycle performance. It is difficult to maintain intimate contact between the inorganic solid-state electrolyte and the electrode particles, and whether or not the solid-state contact is good determines the reversible capacity and capacity retention rate of the all-solid-state battery, so it is critical to optimize these solid-state interfaces in the all-solid-state battery. The composite negative electrode generally comprises a negative electrode active material, a solid electrolyte, a conductive agent and a polymer binder, wherein the polymer binder can connect all solid components, keep good solid-solid interface close contact, and further realize high reversible capacity and capacity retention rate of the all-solid-state battery.
The prior art has the defects that:
during charge and discharge cycles of the battery, the volume of the negative electrode active material changes along with the intercalation and deintercalation of lithium ions, and particularly, the volume of the silicon material tends to change by 120 to 300 percent or even more than 300 percent, which deteriorates interface contact and thus causes the performance of the battery to be reduced.
The current dry binder Polytetrafluoroethylene (PTFE) can react with lithium ions on the surface of the negative electrode to generate lithium fluoride, so that the bonding effect is weakened and the capacity is reduced.
Accordingly, there is a need to provide a new adhesive to solve the above-mentioned problems.
Disclosure of Invention
The application avoids the side reaction of PTFE to the negative electrode by using the fibrous EVA (ethylene-vinyl acetate copolymer) of the elastic polymer binder, and the fibrous EVA of the elastic polymer binder can relieve the volume change of the negative electrode active material of the all-solid-state composite negative electrode plate in the charge and discharge process, enhance the interface contact of all components in the all-solid-state composite negative electrode plate, and develop the practical lithium ion battery with long cycle life. In the present application, EVA (ethylene-vinyl acetate Copolymer/ethylene-vinyl acetate Copolymer, ETHYLENE VINYL ACETATE Copolymer) is copolymerized with ethylene and vinyl acetate, in which VA (vinyl acetate) is one of the components of EVA.
Some embodiments of the present application provide an all-solid-state composite negative electrode sheet comprising: the cathode active material, the solid electrolyte, the conductive agent and the binder, wherein the binder is fibrous ethylene-vinyl acetate copolymer, and the mass ratio of the fibrous ethylene-vinyl acetate copolymer to the all-solid composite cathode pole piece is 3-15: 70-115. In the all-solid-state composite anode sheet, EVA (ethylene-vinyl acetate copolymer) can suppress the volume change of the anode active material, especially in the all-solid-state composite anode sheet. Specifically, fibrous EVA forms a three-dimensional cross-linked network inside the all-solid-state composite negative electrode plate so as to effectively fix each component and effectively inhibit stress accumulation caused by volume change of the negative electrode active material.
In some embodiments, the mass ratio of the fibrous ethylene-vinyl acetate copolymer to the all-solid-state composite negative electrode sheet is 3-10: 98-115, wherein the mass ratio of the anode active material to the solid electrolyte to the conductive agent to the binder is 50-70: 10-30: 5-10: 3-10.
In some embodiments, the mass content of vinyl acetate in the fibrous ethylene-vinyl acetate copolymer is between 10% -30% based on the mass of the fibrous ethylene-vinyl acetate copolymer.
In some embodiments, the ethylene-vinyl acetate copolymer has a melting point between 60 ℃ and 100 ℃.
In some embodiments, the fibrous ethylene-vinyl acetate copolymer has a fiber diameter in the range of 100nm to 200nm, and the fibrous ethylene-vinyl acetate copolymer forms a three-dimensional cross-linked network inside the all-solid-state composite negative electrode sheet. In this range, the ethylene chain segment in the fibrous EVA provides an overall network supporting effect, and the softer vinyl acetate chain segment enables the fibrous EVA to have high elasticity, and benefits from the synergistic effect between ethylene and the vinyl acetate chain segment, so that the all-solid-state composite negative electrode plate can adapt to volume change in the circulation process and effectively lighten internal stress. The stable mechanical interface formed by the fibrous EVA cross-linked network is beneficial to the diffusion kinetics of lithium ions and can improve the rate capability of the composite anode.
In some embodiments, in the volume-based particle size distribution, the particle size of the anode active material from the small particle size side up to 50% by volume is 5 μm to 10 μm.
In some embodiments, the solid electrolyte has a particle size of 2 μm to 4 μm from a small particle size side up to 50% by volume in a volume-based particle size distribution.
In some embodiments, the negative electrode active material is a graphite-based material, a silicon material, or a composite material of both.
In some embodiments, the graphite-based material includes natural graphite and artificial graphite, and the silicon material includes crystalline silicon, amorphous silicon, and silicone.
In some embodiments, the conductive agent is a one-dimensional material including one or more of carbon fibers and carbon nanotubes, wherein the carbon fibers are at least one of Carbon Nanofibers (CNF), vapor Grown Carbon Fibers (VGCF), vapor Grown Carbon Nanofibers (VGCNF), and the solid state electrolyte is one or more of an oxide solid state electrolyte, a sulfide solid state electrolyte, and a halide solid state electrolyte.
Other embodiments of the present application provide an all-solid-state battery comprising the above all-solid-state composite negative electrode tab.
In summary, the fibrous EVA is utilized to relieve the volume change of the negative electrode active material of the all-solid-state composite negative electrode plate in the charge and discharge process, and the interface contact of all components in the all-solid-state composite negative electrode plate is enhanced, so that the cycle performance of the all-solid-state battery is improved.
Detailed Description
Batteries such as lithium ion batteries, sodium ion batteries, and potassium ion batteries are increasingly challenging for new energy applications. In general, in a battery, a volume change of a negative electrode active material occurs during a cycle, and particularly, a volume change of 120% to 300% or even more than 300% of a silicon material tends to occur, which results in poor cycle performance of the battery. However, EVA (ethylene-vinyl acetate copolymer)) can suppress the volume change of the anode active material, especially in all-solid-state composite anode sheets. Specifically, fibrous EVA forms a three-dimensional cross-linked network inside the all-solid-state composite negative electrode plate so as to effectively fix each component and effectively inhibit stress accumulation caused by volume change of the negative electrode active material. The ethylene chain segment in the fibrous EVA provides an integral network supporting effect, the softer vinyl acetate chain segment enables the fibrous EVA to have high elasticity, and the fibrous EVA benefits from the synergistic effect between ethylene and the vinyl acetate chain segment, so that the all-solid-state composite negative electrode plate can adapt to volume change in the circulation process and effectively lighten internal stress. The stable mechanical interface formed by the fibrous EVA cross-linked network is beneficial to the diffusion kinetics of lithium ions and can improve the rate capability of the composite anode. And meanwhile, the fibrous EVA used for the all-solid-state composite negative electrode plate can avoid side reaction of the traditional dry adhesive PTFE on the negative electrode. The beneficial effects are benefited, and all components in the all-solid-state composite negative electrode plate can still keep close contact after long-time circulation, so that the long-circulation performance and the rate performance of the all-solid-state battery operated under low pressure are improved.
In some embodiments, the low melting point EVA is more susceptible to mechanical deformation and fiber after ball milling mixing with the negative electrode active material, solid electrolyte and conductive agent under certain conditions to obtain the desired fiber EVA.
Specifically, the application provides an all-solid-state composite negative electrode plate, which comprises: a negative active material, a solid electrolyte, a conductive agent, and a binder. In some embodiments, the solid-state electrolyte enhances ion transport of the all-solid composite negative electrode sheet, the conductive agent enhances electron transport of the all-solid composite negative electrode sheet, and the binder enhances adhesion of the components of the all-solid composite negative electrode sheet, and the binder is a polymeric compound for binding the electrode negative electrode active material, the solid-state electrolyte, and the conductive agent together while adhering to the current collector. In a further embodiment, the binder is a fibrous ethylene-vinyl acetate copolymer, and the mass ratio of the fibrous ethylene-vinyl acetate copolymer (EVA) to the all-solid-state composite negative electrode sheet is 3-15: 70-115. In the all-solid-state composite anode sheet, EVA (ethylene-vinyl acetate copolymer) can suppress the volume change of the anode active material, especially in the all-solid-state composite anode sheet. Specifically, fibrous EVA forms a three-dimensional cross-linked network inside the all-solid-state composite negative electrode plate so as to effectively fix each component and effectively inhibit stress accumulation caused by volume change of the negative electrode active material.
In some embodiments, the mass ratio of fibrous EVA to the all-solid-state composite negative electrode sheet is 3-10: 98-115, in this range, the stable mechanical interface formed by the crosslinked network of the EVA binder is beneficial to maintaining the internal ion and electron transmission of the all-solid composite negative electrode plate, and can improve the rate capability of the all-solid composite negative electrode plate. In addition, the mass ratio of the anode active material, the solid electrolyte, the conductive agent and the binder is 50-70: 10-30: 5-10: 3-10. Within this range, the components within the all-solid-state composite negative electrode tab can remain in intimate contact after long-term cycling, thereby improving the long-cycle performance and rate capability of an all-solid-state battery operating at low pressures.
In some embodiments, the mass content of vinyl acetate in the fibrous ethylene-vinyl acetate copolymer is between 10% and 30% based on the mass of the fibrous ethylene-vinyl acetate copolymer. In some embodiments, the ethylene-vinyl acetate copolymer has a melting point between 60 ℃ and 100 ℃. In some embodiments, the fibrous ethylene-vinyl acetate copolymer has a fiber diameter in the range of 100nm to 200nm and forms a three-dimensional cross-linked network within the all-solid-state composite negative electrode sheet. In this range, the ethylene chain segment in the fibrous EVA provides an overall network supporting effect, and the softer vinyl acetate chain segment enables the fibrous EVA to have high elasticity, and benefits from the synergistic effect between ethylene and the vinyl acetate chain segment, so that the all-solid-state composite negative electrode plate can adapt to volume change in the circulation process and effectively lighten internal stress. The stable mechanical interface formed by the fibrous EVA cross-linked network is beneficial to the diffusion kinetics of lithium ions and can improve the rate capability of the composite anode.
In some other embodiments, in the volume-based particle size distribution, the particle diameter (D50) of the anode active material from the small particle diameter side up to 50% by volume is 5 μm to 10 μm, and the particle diameter (D50) of the solid electrolyte from the small particle diameter side up to 50% by volume is 2 μm to 4 μm. The applicant finds in the study that by controlling the particle sizes of the anode active material and the solid electrolyte in the corresponding ranges, the porosity of the all-solid composite anode piece can be reduced to the greatest extent, and an ion transmission path is increased, and optionally, the performance of the all-solid composite anode piece can be improved to the greatest extent when the anode active material and the solid electrolyte are compounded with a one-dimensional conductive agent and a fibrous EVA binder with high viscoelasticity for use.
In an embodiment, the anode active material may be a graphite-based material including, but not limited to, natural graphite (bulk graphite, flake graphite, earth-like graphite), artificial graphite (single crystal graphite, polycrystalline graphite, pyrolytic graphite, graphite fibers, etc.), or a silicon material including, but not limited to, crystalline silicon, amorphous silicon, and organic silicon, or a composite material of both.
In some embodiments, the conductive agent is a one-dimensional material including one or more of carbon fibers and carbon nanotubes, wherein the carbon fibers are at least one of Carbon Nanofibers (CNF), vapor Grown Carbon Fibers (VGCF), vapor Grown Carbon Nanofibers (VGCNF). The applicant finds that the problems of loosening and falling off of the zero-dimensional conductive agent and the like are caused by the fact that the nano-size particle size of the zero-dimensional conductive agent cannot be completely bound by the fibrous EVA adhesive in the research, the electron transmission is hindered, and the problem can be effectively avoided by adopting the one-dimensional conductive agent with a larger length-diameter ratio.
Further, in the above-described embodiments, the solid electrolyte is one or more of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.
Still further embodiments of the present application provide an all-solid-state battery including an all-solid composite negative electrode tab according to the above, wherein the operating pressure of the all-solid-state battery is lower than the pressure of the external environment.
In the embodiment, the three-position cross-linked network formed by the fibrous EVA adhesive in the all-solid-state composite negative electrode plate can effectively inhibit stress accumulation caused by volume change of the negative electrode active material, so that the long-cycle performance and the rate performance of the all-solid-state battery operated under low pressure are improved.
In addition, still other embodiments of the present application also provide a preparation method of the above all-solid-state composite negative electrode sheet, including the following steps:
S1, mixing a corresponding amount of anode active material, solid electrolyte, a conductive agent and a binder in a glove box to form a mixture, wherein the mass ratio of the anode active material to the solid electrolyte to the conductive agent to the binder is 50-70: 10-30: 5-10: 3-10;
S2, performing ball milling treatment on the mixture to obtain a bulk all-solid-state composite anode material;
S3, repeatedly rolling the bulk all-solid-state composite anode material to a certain thickness at a preset temperature, and compositing the material with an anode current collector to obtain the all-solid-state composite anode piece.
In the preparation method, the rotating speed is 50-200 rpm during ball milling and mixing in the step S2, the mixing time is 0.1-0.5 h, the diameter of ball milling zirconium beads is 5 mm-20 mm, and the ball-to-material ratio is (20-50): 1. the applicant finds in the research process that the adoption of the ball milling conditions can lead the raw materials to be mixed more uniformly so as to improve the interface compatibility among the components; meanwhile, after high-energy ball milling and mixing, the heat generated by the high-energy ball milling and mixing can enable the EVA adhesive with low melting point to be more easily subjected to mechanical deformation and fiber shape, and the fiber EVA forms a three-dimensional cross-linked network inside the all-solid-state composite negative electrode plate so as to effectively fix all components. Meanwhile, the ball milling conditions can lead the fibrous EVA fiber diameter to be concentrated in the range of 100 nm-200 nm, other composite anode components can be well wrapped while the fibrous EVA fiber has good viscoelasticity, and if the ball milling parameters exceed the range, the EVA fiber diameter deviates from a normal value, so that the performance of the composite anode is affected.
Optionally, in the step S2, the rotation speed is 100rpm during ball milling and mixing, the ball milling time is 0.2 h, the diameter of ball milling zirconium beads is 10mm, and the ball-to-material ratio is 30:1.
Optionally, in the step S3, the rolling temperature ranges from 100 ℃ to 150 ℃, the current collector is carbon-coated aluminum foil, the thickness of the current collector is 6 μm to 20 μm, and the final composite negative surface load is 1 mAh cm -2.
The following takes all-solid-state lithium ion battery as an example
All-solid-state composite negative pole piece
The all-solid-state composite negative electrode plate in the all-solid-state battery provided by the application comprises a negative electrode current collector commonly used in the field, and a negative electrode active material, a solid electrolyte, a conductive agent and a binder which are arranged on the negative electrode current collector. The negative electrode active material may be a graphite-based material, which may include, but is not limited to, natural graphite (bulk graphite, flake graphite, earth graphite), or artificial graphite (single crystal graphite, polycrystalline graphite, pyrolytic graphite, graphite fibers, etc.), a silicon material, or a composite material of both, and the silicon material includes, but is not limited to, crystalline silicon, amorphous silicon, and organosilicon. The solid electrolyte is one or more of oxide solid electrolyte, sulfide solid electrolyte and halide solid electrolyte, the binder is fibrous EVA, the mass content of VA in the fibrous EVA is 10% -30% based on the mass of the fibrous EVA, and the melting point of the EVA is 60 ℃ -100 ℃. In some embodiments, the fibrous EVA has a fiber diameter in the range of 100nm to 200 nm. In some embodiments, the conductive agent is a one-dimensional material including one or both of carbon fibers and carbon nanotubes. The carbon fiber is at least one of Carbon Nanofiber (CNF), vapor Grown Carbon Fiber (VGCF) and Vapor Grown Carbon Nanofiber (VGCNF).
In addition, the negative electrode current collector may be a carbon-coated aluminum foil current collector, however, other negative electrode current collectors commonly used in the art may be employed.
Counter electrode pole piece
The active material of the counter electrode sheet may also be an alloy comprising indium, lithium, indium, aluminum or at least two of the foregoing metals.
Solid electrolyte layer
The solid electrolyte layer consists of solid electrolyte and a binder, wherein the solid electrolyte is one or more of oxide solid electrolyte, sulfide solid electrolyte and halide solid electrolyte, the binder is one or more of nitrile rubber, styrene-butadiene rubber, linear triblock copolymer, polyvinylidene fluoride or Polytetrafluoroethylene (PTFE), and optionally, the mass ratio of the solid electrolyte to the binder in the solid electrolyte layer is 90-100: 0.5 to 10.
All-solid-state battery
Sequentially placing the all-solid-state composite anode pole piece, the solid electrolyte layer and the counter electrode pole piece into a mould for assembly; and pressurizing after assembly, and screwing up nuts at the top ends of the stand columns to obtain the all-solid-state lithium ion battery under constant pressure.
Note that: the assembly process was completed in an argon atmosphere glove box.
It should be noted that the all-solid-state battery prepared by the above method is an all-solid-state lithium ion battery. But the battery prepared by the application can also be an all-solid-state sodium ion battery or a potassium ion battery.
Those skilled in the art will appreciate that the above-described methods of preparing a battery are merely examples. Other methods commonly used in the art may be employed without departing from the present disclosure.
The reagents and materials used in the present invention are commercially available.
The present invention is not particularly limited to the above-described battery assembly method, and may be applied to an assembly method known to those skilled in the art. In addition, the technical scheme can be applied to all-solid-state lithium ion batteries which are commonly used, all-solid-state sodium ion batteries, all-solid-state potassium ion batteries and other various kinetic batteries.
The following examples and comparative examples are set forth to better illustrate the present application.
Example 1
All-solid-state composite negative pole piece
The all-solid-state composite negative electrode sheet comprises a negative electrode active material, a solid electrolyte, a conductive agent and a binder, wherein in the embodiment, the mass ratio of the negative electrode active material to the solid electrolyte to the conductive agent to the binder is 60:30:5:5.
The binder was fibrous EVA (ethylene-vinyl acetate copolymer) with a VA mass content of 18% and an EVA melting point of 84℃and a melt index of 2.5, based on the mass of fibrous EVA.
The negative electrode active material is silicon carbon particles, specifically Si-C, and is derived from Shenzhen Yue chemical Co., ltd, model number BSC390, and D50 of 8.5 μm.
The solid electrolyte is sulfide solid electrolyte, specifically Li 6PS5 Cl, which is sourced from Shandong Xinjie lithium electric Co Ltd, and has the model number of LPSCl-M and the D50 of 3 mu M.
The conductive agent was VGCF, available from Showa Denko Co., ltd., model VGCF-H.
The preparation method of the all-solid-state composite negative electrode plate comprises the following steps:
S1, mixing the following components in mass ratio of 60:30:5:5, mixing silicon carbon particles, li 6PS5 Cl, a conductive agent VGCF and a binder EVA in a glove box to form a mixture;
s2, performing ball milling treatment on the mixture to obtain a bulk all-solid-state composite anode material;
S3, repeatedly rolling the bulk all-solid-state composite anode material at 100 ℃ until the surface capacity is 2 mAh cm -2, and compositing the composite anode material with a 12-mu m carbon-coated aluminum foil current collector to obtain the all-solid-state composite anode piece.
The rotational speed of ball milling treatment in the step S2 is 100 rpm, the ball milling time is 0.2 h, the diameter of ball milling zirconium beads is 10 mm, and the ball-to-material ratio is 30:1.
Counter electrode pole piece
The counter electrode sheet is a lithium indium alloy sheet (corresponding diameter phi=10 mm).
Solid electrolyte layer
Consists of a solid electrolyte (Li 6PS5 Cl) and a binder (PTFE); the mass ratio of the two is 99:1.
All-solid-state lithium ion battery
The all-solid-state lithium ion battery consists of the all-solid-state composite negative electrode plate, the counter electrode plate and the solid electrolyte layer, and the preparation steps are as follows:
Sequentially placing the all-solid-state composite negative electrode plate, the solid electrolyte layer and the lithium indium alloy plate into a die for assembly; and pressurizing to 100MPa after assembling, and screwing up nuts at the top ends of the stand columns to obtain the all-solid-state lithium ion battery under constant pressure. It should be noted that the assembly process was completed in an argon atmosphere glove box, and the diameters of the all-solid composite negative electrode tab, the solid electrolyte layer, and the lithium indium alloy sheet were all 10 mm.
Example 2
In accordance with the preparation method of example 1, except that the mass ratio of the anode active material, the solid electrolyte, the conductive agent, and the binder in example 2 was 60:30:5:3.
Example 3
In accordance with the preparation method of example 1, except that the mass ratio of the anode active material, the solid electrolyte, the conductive agent, and the binder in example 3 was 60:30:5:7.
Example 4
In accordance with the preparation method of example 1, except that the mass ratio of the anode active material, the solid electrolyte, the conductive agent, and the binder in example 4 was 60:30:5:10.
Example 5
In accordance with the preparation method of example 1, except that the mass ratio of the anode active material, the solid electrolyte, the conductive agent, and the binder in example 5 was 70:15:8:5.
Example 6
In accordance with the preparation method of example 1, except that the mass ratio of the anode active material, the solid electrolyte, the conductive agent, and the binder in example 6 was 70:30:10:5.
Example 7
In accordance with the preparation method of example 1, except that the mass ratio of the anode active material, the solid electrolyte, the conductive agent, and the binder in example 7 was 50:10:5:5.
Example 8
Consistent with the preparation method of example 1, except that the D50 of the anode active material in example 8 was 5 μm and the D50 of the solid-state electrolyte was 2 μm.
Example 9
Consistent with the preparation method of example 1, except that the D50 of the anode active material in example 9 was 10 μm and the D50 of the solid-state electrolyte was 4 μm.
Example 10
The preparation method of example 1 was identical, except that the VA content was 10% by mass and the EVA melting point was 97℃in example 10.
Example 11
The preparation process was identical to that of example 1, except that the VA content was 25% by mass and the EVA melting point was 70℃in example 11.
Example 12
The preparation process was identical to that of example 1, except that the VA content was 30% by mass and the EVA melting point was 62℃in example 12.
Example 13
Consistent with the preparation method of example 1, except that the pressurization of the assembled all-solid-state lithium ion battery in example 13 was reduced from 100 MPa to 5 MPa.
Example 14
Consistent with the preparation method of example 1, except that the melt index of EVA in the all-solid composite positive electrode sheet in example 14 was increased from 2.5 of example 1 to 400. Accordingly, the melting point of EVA is reduced from 84 ℃ to 76 ℃ under the condition that the VA content is 18%.
Example 15
In accordance with the preparation method of example 1, except that the mass ratio of the anode active material, the solid electrolyte, the conductive agent, and the binder in example 15 was 60:30:5:15.
Example 16
The same preparation method as in example 1 was followed, except that the conductive agent in the all-solid-state composite negative electrode sheet in example 16 was zero-dimensional conductive agent Super P (Super P, tianjin you chemical industry Co., ltd.).
Example 17
The preparation method of example 1 was identical, except that the negative electrode active material of example 17 used small-sized silicon carbon particles instead of the original silicon carbon particles.
The small-size silicon-carbon particles are specifically Si-C, and are derived from Shenzhen Zhongyue chemical Co., ltd, and are model BSC400, and D50 is 3.5 μm.
Example 18
Consistent with the preparation method of example 12, except that the melt index of EVA in the all-solid composite positive electrode sheet in example 18 was increased from 2.5 of example 12 to 400. Accordingly, the melting point of EVA is reduced from 62 ℃ to 58 ℃ under the condition that the VA content is 30%.
Comparative example 1
In agreement with the preparation method of example 1, except that the all-solid composite anode sheet in comparative example 1 does not contain fibrous EVA as a binder, i.e., the mass ratio of anode active material, solid electrolyte, conductive agent and binder in comparative example 1 is 60:30:5:0, and the mass of the obtained all-solid composite anode powder was 99% of the mass of the all-solid composite anode powder in example 1.
Comparative example 2
The same preparation method as in example 1 was followed, except that PVDF was used as the binder in the all-solid-state composite negative electrode sheet of comparative example 2, which was derived from Acomax and was designated as Film 302 PGM TR.
Comparative example 3
The same preparation method as in example 1 was followed, except that PTFE was used as the binder in the all-solid-state composite negative electrode sheet in comparative example 3, which was derived from Dajinfu chemical Co., ltd., model M-392.
Comparative example 4
The same preparation method as in example 1 was followed, except that the binder in the all-solid-state composite negative electrode sheet in comparative example 4 was PTFE, which was derived from large gold fluorine chemical industry (china) limited, model M-392, and the pressurization of the assembled all-solid-state lithium ion battery was reduced from 100 MPa to 5 MPa.
Comparative example 5
Consistent with the preparation method of example 1, except that the ball milling conditions in the preparation of the all-solid composite negative electrode sheet in comparative example 5 were: the rotation speed is 30 rpm during ball milling and mixing, the mixing time is 0.1 h, the diameter of ball milling zirconium beads is 10mm, and the ball-to-material ratio is 30:1.
Comparative example 6
Consistent with the preparation method of example 1, except that the ball milling conditions in the preparation of the all-solid composite negative electrode sheet in comparative example 6 were: the rotation speed during ball milling and mixing is 1500 rpm, the mixing time is 6h, the diameter of ball milling zirconium beads is 10mm, and the ball-to-material ratio is 30:1.
Performance test method
1. The average diameter was obtained by observing the diameter of EVA fibers in the composite anode using a Scanning Electron Microscope (SEM) and arbitrarily extracting 50 EVA fiber images.
2. Performing long-cycle charge and discharge on the all-solid-state lithium ion batteries prepared in examples 1-18 and comparative examples 1-6 after constant volume in a 25 ℃ environment, and measuring the normal-temperature cycle number of the all-solid-state lithium ion batteries; the test condition is that the battery is subjected to long-cycle charge and discharge test after the constant volume, and the first-cycle constant volume discharge specific capacity and the normal-temperature cycle number when the SOH is 50% are recorded in the process; the working voltage range is-0.615-1.4V, the constant volume multiplying power is 0.1C, and the normal temperature cycle testing multiplying power is 0.3C.
The test results are shown in Table 1 below.
TABLE 1 all solid state lithium ion battery Performance test results for examples 1-18 and comparative examples 1-6
| Group of | Mass ratio of negative electrode active material, solid electrolyte, conductive agent and binder | Negative active material (D50) | Solid electrolyte (D50) | VA content/EVA melting Point | Average diameter (nm) of fibrous EVA fibers | First-turn discharge specific capacity (mAh/g) | Circulation performance normal temperature cycle number (50% SOH) |
| Example 1 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 153 | 372 | 186 |
| Example 2 | 60：30：5：3 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 145 | 378 | 154 |
| Example 3 | 60：30：5：7 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 150 | 365 | 173 |
| Example 4 | 60：30：5：10 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 157 | 355 | 158 |
| Example 5 | 70：15：8：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 151 | 352 | 164 |
| Example 6 | 70：30：10：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 148 | 385 | 172 |
| Example 7 | 50：10：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 147 | 359 | 156 |
| Example 8 | 60：30：5：5 | Silicon carbon particles (5 μm) | Li6PS5Cl(2μm) | 18%/84℃ | 155 | 368 | 179 |
| Example 9 | 60：30：5：5 | Silicon carbon particles (10 μm) | Li6PS5Cl(4μm) | 18%/84℃ | 153 | 374 | 183 |
| Example 10 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 10%/97℃ | 190 | 382 | 174 |
| Example 11 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 25%/70℃ | 133 | 361 | 189 |
| Example 12 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 30%/62℃ | 118 | 355 | 182 |
| Example 13 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 166 | 336 | 131 |
| Example 14 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/76℃ | 141 | 366 | 185 |
| Example 15 | 60：30：5：15 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 153 | 274 | 118 |
| Example 16 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 148 | 332 | 136 |
| Example 17 | 60：30：5：5 | Silicon carbon particles (3.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 136 | 298 | 104 |
| Example 18 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/58℃ | 192 | 325 | 147 |
| Comparative example 1 | 60：30：5：0 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | NA | NA | 397 | 26 |
| Comparative example 2 | The binder adopts PVDF60:30:5:5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | NA | NA | 374 | 35 |
| Comparative example 3 | The bonding agent adopts PTFE60:30:5:5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | NA | NA | 363 | 68 |
| Comparative example 4 | The bonding agent adopts PTFE60:30:5:5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | NA | NA | 186 | 15 |
| Comparative example 5 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 510 | 339 | 92 |
| Comparative example 6 | 60：30：5：5 | Silicon carbon particles (8.5 μm) | Li6PS5Cl(3μm) | 18%/84℃ | 20 | 307 | 137 |
As can be seen from examples 1 and 13, all-solid lithium ion batteries employing fibrous EVA as the binder in all-solid composite negative electrode sheets still have relatively good reversible capacity and cycling performance when the operating pressure is reduced from 100 MPa to a lower operating pressure of 5 MPa. That is, with the all-solid-state lithium ion battery provided by the application, the battery can be operated at a lower operating pressure of 5 MPa without affecting the performance thereof. While it is known from comparative examples 3 and 4 that when the operating pressure is reduced from 100 MPa to lower operating pressure 5 MPa, the performance of all solid state lithium ion batteries employing PTFE as the binder in the composite negative electrode sheet is deteriorated because of the poor viscoelasticity of PTFE, it is seen that the battery formed from non-fibrous EVA as the binder does not work well at lower operating pressure 5 MPa. Based on the above, comparing examples 1-19 with comparative examples 1-4, it is known that fibrous EVA is used as the binder in the all-solid-state composite negative electrode sheet, and the mass ratio of fibrous EVA to all-solid-state composite negative electrode sheet is 3-15: 70-115, so that the all-solid-state composite positive electrode plate has high interfacial adhesion and high elasticity, and can effectively improve the normal-temperature cycle number of the battery, thereby improving the cycle performance and the multiplying power performance of the all-solid-state lithium ion battery, especially in the embodiments shown in embodiments 1-14, the improvement effect is obvious, and the performance of the all-solid-state lithium ion battery is improved to a certain extent for embodiments 15-19, but the effect is limited (refer to the analysis below in particular). When no binder or other types of binders such as PTFE or PVDF are used, the cycle performance of the battery is deteriorated, and the number of cycles at normal temperature is significantly reduced, especially at a lower pressure of 5 MPa. This is because the adhesion effect of PTFE is poor; and PVDF has a high melting point, cannot be mechanically deformed and fibrous after ball milling, and cannot function to adhere a negative electrode active material, a solid electrolyte and a conductive agent, so that the battery cycle performance is poor.
Specifically, as can be seen from examples 1 to 7, example 15 and comparative example 1, when fibrous EVA is used as the binder in the all-solid-state composite negative electrode sheet, the cycle performance and rate performance of the all-solid-state lithium ion battery can be effectively improved. As can be seen by comparing examples 1 to 7 with example 15, when the mass ratio of the anode active material, the solid electrolyte, the conductive agent, and the binder (fibrous EVA) is satisfied, it is 50 to 70: 10-30: 5-10: and when the conditions are 3-10, the normal-temperature cycle number of the battery can be effectively improved, so that the cycle performance and the rate capability of the all-solid-state lithium ion battery are improved. In contrast, as can be seen from example 15, when the mass ratio of the fibrous EVA binder to the negative electrode active material, the solid electrolyte, and the conductive agent is not within the above range, the cycle performance of the all-solid lithium ion battery is affected, a certain degree of degradation occurs, and the number of cycles at normal temperature is also reduced. Further, as can be seen from examples 1-6, when the mass ratio of fibrous EVA to all-solid composite negative electrode sheet is about 3 to 10: and when 98-115, the improved performance of the all-solid-state lithium ion battery is better, and the better cycle performance and rate capability of the all-solid-state lithium ion battery can be obtained. The mass ratio of the fibrous ethylene-vinyl acetate copolymer (EVA) to the all-solid-state composite positive electrode plate is in the range, so that a stable mechanical interface formed by a crosslinked network of the EVA binder is beneficial to maintaining the internal ion and electron transmission of the all-solid-state composite negative electrode plate, and the rate capability of the all-solid-state composite negative electrode plate can be improved.
As can be seen from examples 1 and examples 8 to 9, the all-solid-state lithium ion battery also has good cycle performance and rate performance when the D50 of the anode active material is in the range of 5 to 10 μm and the D50 of the solid-state electrolyte is in the range of 2 to 4 μm.
As can be seen from examples 1, 10-12 and 18, the fibrous EVA has a VA content of 10% -30% by mass, and the EVA has a melting point of 60 ℃ -100 ℃ and the all-solid-state lithium ion battery has good cycle performance and rate performance. Further, it can be seen from example 18 that when the EVA melting point is lower than 60 ℃, the first-turn specific capacity and cycle performance of the battery are affected, probably because, when the EVA melting point is lower than 60 ℃, ion transport performance is affected in the interior of the negative electrode material layer in which it participates, thereby affecting cycle performance and rate performance of the composite negative electrode.
From examples 1 and 14, it can be seen that the melting point of EVA correlates with both VA content and melt index.
Further, as can be seen from examples 1 to 18 and comparative examples 5 to 6, although fibrous EVA formed by ball milling contributes to improvement of cycle performance and rate performance of the formed all-solid lithium ion battery, the improvement effect in examples 16 to 17 is limited. It can be seen that when the ball milling conditions are satisfied: the rotating speed is 50-200 rpm during ball milling and mixing, the mixing time is 0.1-0.5 h, the diameter of ball milling zirconium beads is 5-20 mm, and the ball-material ratio is (20-50): 1, the fiber diameter of the fibrous EVA can be concentrated in the range of 100-200 nm, and other composite anode components can be well wrapped while the fibrous EVA has good viscoelasticity. If the ball milling parameters exceed the above range, the fiber diameter of the fibrous EVA deviates from the normal value, and the performance of the all-solid-state composite negative electrode plate is affected to a certain extent. For comparative example 5, the ball milling conditions lead to larger fiber diameter of the formed fibrous EVA, so that the limited amount of binder can not well tie up silicon carbon particles, and further cause the partial material of the all-solid-state composite negative electrode plate to fall off and powder, thus reducing the structural stability of the all-solid-state composite negative electrode plate; and for comparative example 6, the ball milling conditions of the catalyst lead to smaller fiber diameter of the fibrous EVA, so that the contact area of the insulating EVA binder, the anode active material and the solid electrolyte is increased, the ion transmission path is blocked, and the battery performance is further affected.
As can be seen from examples 1 and 16, when the one-dimensional conductive agent is replaced with the zero-dimensional conductive agent, the nano-size thereof cannot maintain good contact with other composite anode components during the cycle, and thus the battery performance is affected, thereby being disadvantageous in improving the all-solid-state lithium ion battery.
As can be seen from examples 1 and 17, when D50 of the anode active material and the solid electrolyte are not in the corresponding range of the present invention (D50 of the anode active material is in the range of 5 μm to 10 μm and D50 of the solid electrolyte is in the range of 2 μm to 4 μm), the porosity of the composite anode is high, thereby reducing the ion transport path to some extent.
In summary, the fibrous EVA is utilized to relieve the volume change of the negative electrode active material of the all-solid-state composite negative electrode plate in the charge and discharge process, and the interface contact of all components in the all-solid-state composite negative electrode plate is enhanced, so that the cycle performance and the multiplying power performance of the all-solid-state battery are improved.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present invention. Those skilled in the art will appreciate that they may readily use the present invention as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the invention.
Claims (10)
1. An all-solid-state composite negative electrode sheet, comprising: a negative active material, a solid electrolyte, a conductive agent, and a binder,
The adhesive is a fibrous ethylene-vinyl acetate copolymer, and the mass ratio of the fibrous ethylene-vinyl acetate copolymer to the all-solid-state composite negative electrode plate is 3-15: 70 to 115 of the total number of the components,
Wherein the fiber diameter of the fibrous ethylene-vinyl acetate copolymer is within the range of 100nm to 200 nm.
2. The all-solid-state composite negative electrode sheet according to claim 1, wherein the mass ratio of the fibrous ethylene-vinyl acetate copolymer to the all-solid-state composite negative electrode sheet is 3-10: 98-115, wherein the mass ratio of the anode active material to the solid electrolyte to the conductive agent to the binder is 50-70: 10-30: 5-10: 3-10.
3. The all-solid-state composite negative electrode tab of claim 1, wherein,
Based on the mass of the fibrous ethylene-vinyl acetate copolymer, the mass content of vinyl acetate in the fibrous ethylene-vinyl acetate copolymer is between 10% and 30%; and/or the number of the groups of groups,
The melting point of the ethylene-vinyl acetate copolymer is 60-100 ℃.
4. The all-solid-state composite negative electrode tab of claim 1, wherein the fibrous ethylene-vinyl acetate copolymer forms a three-dimensional cross-linked network inside the all-solid-state composite negative electrode tab.
5. The all-solid-state composite negative electrode sheet according to claim 1, wherein in the volume-based particle size distribution, the particle diameter of the negative electrode active material reaching 50% of the volume accumulation from the small particle diameter side is 5 μm to 10 μm.
6. The all-solid-state composite negative electrode sheet according to claim 1, wherein in the volume-based particle size distribution, the particle size of the solid electrolyte from the small particle size side up to 50% by volume accumulation is 2 μm to 4 μm.
7. The all-solid-state composite negative electrode sheet according to claim 1, wherein the negative electrode active material is a graphite-based material, a silicon material, or a composite material formed by combining the graphite-based material and the silicon material.
8. The all-solid-state composite negative electrode tab of claim 7, wherein the graphite-based material comprises natural graphite and artificial graphite, and the silicon material comprises crystalline silicon, amorphous silicon, and organic silicon.
9. The all-solid-state composite negative electrode tab of claim 1, wherein the conductive agent is a one-dimensional material comprising one or more of carbon fibers and carbon nanotubes, wherein the carbon fibers are at least one of Carbon Nanofibers (CNF), vapor Grown Carbon Fibers (VGCF), vapor Grown Carbon Nanofibers (VGCNF), and the solid electrolyte is one or more of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.
10. An all-solid-state battery characterized by comprising an all-solid composite negative electrode tab according to any one of the preceding claims 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202411075289.3A CN118588943A (en) | 2024-08-07 | 2024-08-07 | All-solid-state composite negative electrode plate and all-solid-state battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202411075289.3A CN118588943A (en) | 2024-08-07 | 2024-08-07 | All-solid-state composite negative electrode plate and all-solid-state battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118588943A true CN118588943A (en) | 2024-09-03 |
Family
ID=92526961
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202411075289.3A Pending CN118588943A (en) | 2024-08-07 | 2024-08-07 | All-solid-state composite negative electrode plate and all-solid-state battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118588943A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1247640A (en) * | 1997-12-16 | 2000-03-15 | 松下电器产业株式会社 | Non-aqueous electrolyte secondary cell, negative electrode therefor, and method of producing negative electrode |
| CN103022414A (en) * | 2012-12-30 | 2013-04-03 | 无锡富洪科技有限公司 | Lithium ion battery and negative pole piece thereof |
| CN104659412A (en) * | 2015-01-29 | 2015-05-27 | 中国科学院物理研究所 | Lithium-carbon-boron oxide solid electrolyte material containing plane triangle group and battery |
| CN112086645A (en) * | 2020-09-21 | 2020-12-15 | 河南英能新材料科技有限公司 | Lithium battery negative pole piece |
| CN118039793A (en) * | 2024-03-15 | 2024-05-14 | 浙江大学 | Composite positive electrode material of all-solid-state lithium-sulfur battery, preparation method of composite positive electrode material and battery |
| CN118054066A (en) * | 2022-11-10 | 2024-05-17 | 北京车和家信息技术有限公司 | All-solid-state battery, preparation method thereof and vehicle |
-
2024
- 2024-08-07 CN CN202411075289.3A patent/CN118588943A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1247640A (en) * | 1997-12-16 | 2000-03-15 | 松下电器产业株式会社 | Non-aqueous electrolyte secondary cell, negative electrode therefor, and method of producing negative electrode |
| CN103022414A (en) * | 2012-12-30 | 2013-04-03 | 无锡富洪科技有限公司 | Lithium ion battery and negative pole piece thereof |
| CN104659412A (en) * | 2015-01-29 | 2015-05-27 | 中国科学院物理研究所 | Lithium-carbon-boron oxide solid electrolyte material containing plane triangle group and battery |
| CN112086645A (en) * | 2020-09-21 | 2020-12-15 | 河南英能新材料科技有限公司 | Lithium battery negative pole piece |
| CN118054066A (en) * | 2022-11-10 | 2024-05-17 | 北京车和家信息技术有限公司 | All-solid-state battery, preparation method thereof and vehicle |
| CN118039793A (en) * | 2024-03-15 | 2024-05-14 | 浙江大学 | Composite positive electrode material of all-solid-state lithium-sulfur battery, preparation method of composite positive electrode material and battery |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Kamali et al. | Review on carbon and silicon based materials as anode materials for lithium ion batteries | |
| CN108963187B (en) | Silicon-carbon cathode, preparation method thereof, lithium ion battery and electric vehicle | |
| CN110546788A (en) | Polymer binder for lithium battery and manufacturing method | |
| US20110163274A1 (en) | Electrode composite, battery electrode formed from said composite, and lithium battery comprising such an electrode | |
| Cho et al. | Anomalous Si-based composite anode design by densification and coating strategies for practical applications in Li-ion batteries | |
| TWI686001B (en) | Polymer-modified silicon-carbon composite and use thereof | |
| KR102241403B1 (en) | Electrode for an electric energy storage battery comprising a graphite/silicon/carbon fibre composite material | |
| CN113193196B (en) | Multifunctional water-based adhesive for sodium ion battery and application thereof | |
| CN115036471A (en) | Silicon-based composite material and preparation method thereof, negative electrode material of lithium battery and preparation method thereof, and lithium battery | |
| CN117374373A (en) | All-solid-state soft-package battery | |
| CN111384370A (en) | High-capacity density lithium ion battery cathode | |
| CN109817984B (en) | Preparation method of high-power graphite cathode slurry | |
| CN118588943A (en) | All-solid-state composite negative electrode plate and all-solid-state battery | |
| CN118588867A (en) | All-solid-state composite positive electrode plate and all-solid-state battery | |
| KR20220059928A (en) | Slurry composition for negative electrode of lithium secondary battery | |
| CN118588938B (en) | All-solid-state battery positive plate, preparation method thereof and all-solid-state battery | |
| CN118610364B (en) | All-solid-state battery pole piece, preparation method thereof and all-solid-state battery | |
| CN118588941A (en) | All-solid dry method cathode Pole piece and all-solid-state battery | |
| CN116779777B (en) | Lithium iron phosphate positive electrode active material, preparation method thereof, positive electrode plate and lithium ion battery | |
| CN219303702U (en) | Lithium ion battery and negative plate thereof | |
| CN116022783B (en) | Modified graphite negative electrode material and preparation method and application thereof | |
| KR102677989B1 (en) | Method for manufacturing coating solution for secondary battery anode containing carbon-based nanocomposite | |
| US12126004B2 (en) | Fabrication of Si-MWCNT nanocomposites (SMC) as anodes for lithium-ion batteries | |
| TWI756982B (en) | Secondary granulated silicon carbon base battery negative electrode material and preparation method thereof | |
| CN118588942A (en) | All-solid dry method positive electrode plate and all-solid battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |