CN-121983513-A - Negative electrode plate, preparation method thereof and solid-state battery

CN121983513ACN 121983513 ACN121983513 ACN 121983513ACN-121983513-A

Abstract

The application discloses a negative electrode plate, a preparation method thereof and a solid-state battery, and belongs to the technical field of batteries. The third functional layer in the negative electrode plate is used as an electronic insulation-ion conducting layer and is made of an electronic insulation but ion conducting material, so that the transmission of electrons between the negative electrode and the solid electrolyte can be effectively isolated, and side reactions such as decomposition of the solid electrolyte are avoided, and the cycling stability of the battery is improved. The second functional layer is used as a lithium-philic induction-diffusion promoting layer, the adopted nano metal particles have extremely strong lithium-philic property, can be used as uniform lithium deposition induction sites, and can promote lithium diffusion and inhibit growth of lithium dendrites by combining with high conductivity of nano carbon black, so that the safety of the battery is ensured. The first functional layer is used as a core lithium storage layer, the silicon-based material provides basic lithium storage capacity, the second functional layer guides lithium to be stably deposited in a metal form, and the lithium storage capacity of the battery can be greatly improved by combining the high ion conductivity of sulfide electrolyte and the high conductivity of vapor grown carbon fiber.

Inventors

WANG ZHIXUAN
XU FANGLIN
Sun Meici
LI QIUFEN
GUO WEN
LI YANGJIE
Lv Kexuan

Assignees

奇瑞汽车股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260130

Claims (10)

1. The negative electrode plate is characterized by comprising a negative electrode current collector and a negative electrode functional layer arranged on at least one side surface of the negative electrode current collector; The negative electrode functional layer sequentially comprises a first functional layer, a second functional layer and a third functional layer from the direction close to the negative electrode current collector to the direction far away from the negative electrode current collector; the first functional layer comprises a silicon-based material, a sulfide electrolyte and vapor grown carbon fibers; the second functional layer comprises nano carbon black and nano metal particles; the third functional layer comprises at least one of lithium lanthanum zirconium oxide, lithium phosphorus oxygen nitrogen, lithium fluoride and lithium nitride.
2. The negative electrode tab of claim 1 wherein the first functional layer further comprises a first binder; The mass fraction of the silicon-based material in the first functional layer is 60% -80%, the mass fraction of the sulfide electrolyte is 15% -30%, the mass fraction of the vapor grown carbon fiber is 3% -6%, and the mass fraction of the first binder is 2% -4%.
3. The negative electrode tab of claim 2, wherein the sulfide electrolyte is selected from at least one of Li 6 PS 5 Cl、Li 3 PS 4 、Li 10 GeP 2 S 12 、Li 7 P 3 S 11 .
4. The negative electrode tab of claim 2, wherein the silicon-based material is selected from at least one of micro-silicon, nano-silicon, silicon-carbon materials.
5. The negative electrode sheet according to claim 1, wherein the mass ratio of the nano carbon black to the nano metal particles is 1:1-5:1.
6. The negative electrode tab of claim 1, wherein the nano-metal particles are selected from at least one of silver, aluminum, tin, zinc, indium, magnesium.
7. The negative electrode sheet according to claim 1, wherein the particle diameter of the nano carbon black is 20nm to 50nm, and the particle diameter of the nano metal particles is 10nm to 30nm.
8. The negative electrode tab of claim 1, wherein the first functional layer has a thickness of 20 μm to 30 μm, the second functional layer has a thickness of 4 μm to 6 μm, and the third functional layer has a thickness of 50nm to 200nm.
9. A method of producing a negative electrode sheet according to any one of claims 1 to 8, comprising: Providing a negative current collector, first slurry corresponding to the first functional layer and second slurry corresponding to the second functional layer; Coating the first slurry on the surface of the negative electrode current collector, and forming the first functional layer on the surface of the negative electrode current collector to obtain a substrate pole piece; Coating the second slurry on the surface of the substrate pole piece, and forming the second functional layer on the surface of the first functional layer to obtain a pre-composite pole piece; and depositing a material corresponding to a third functional layer on the surface of the pre-composite pole piece, and forming the third functional layer on the surface of the second functional layer to obtain the negative pole piece.
10. A solid-state battery comprising a solid-state electrolyte, a positive electrode tab and a negative electrode tab disposed on both sides of the solid-state electrolyte, wherein the negative electrode tab is as claimed in any one of claims 1 to 8.

Description

Negative electrode plate, preparation method thereof and solid-state battery Technical Field The application relates to the technical field of batteries, in particular to a negative electrode plate, a preparation method thereof and a solid-state battery. Background All-solid-state batteries are regarded as the core development direction of next-generation power batteries because of the advantages of high energy density and excellent safety due to the adoption of solid-state electrolytes instead of liquid electrolytes. The cathode pole piece is used as a key component of the all-solid-state battery, and directly influences the safety, lithium storage capacity and cycling stability of the battery. Disclosure of Invention The embodiment of the application provides a negative electrode plate, a preparation method thereof and a solid-state battery, which can improve the cycling stability of the battery, improve the lithium storage capacity of the battery and ensure the safety of the battery. The technical scheme is as follows: In one aspect, a negative electrode plate is provided, which comprises a negative electrode current collector and a negative electrode functional layer arranged on at least one side surface of the negative electrode current collector; The negative electrode functional layer sequentially comprises a first functional layer, a second functional layer and a third functional layer from the direction close to the negative electrode current collector to the direction far away from the negative electrode current collector; the first functional layer comprises a silicon-based material, a sulfide electrolyte and vapor grown carbon fibers; the second functional layer comprises nano carbon black and nano metal particles; the third functional layer comprises at least one of lithium lanthanum zirconium oxide, lithium phosphorus oxygen nitrogen, lithium fluoride and lithium nitride. In one possible implementation, the first functional layer further includes a first adhesive; The mass fraction of the silicon-based material in the first functional layer is 60% -80%, the mass fraction of the sulfide electrolyte is 15% -30%, the mass fraction of the vapor grown carbon fiber is 3% -6%, and the mass fraction of the first binder is 2% -4%. In another possible implementation, the sulfide electrolyte is selected from at least one of Li6PS5Cl、Li3PS4、Li10GeP2S12、Li7P3S11. In another possible implementation, the silicon-based material is selected from at least one of micro silicon, nano silicon, silicon carbon materials. In another possible implementation manner, the mass ratio of the nano carbon black to the nano metal particles is 1:1-5:1. In another possible implementation, the nano-metal particles are selected from at least one of silver, aluminum, tin, zinc, indium, magnesium. In another possible implementation manner, the particle size of the nano carbon black is 20 nm-50 nm, and the particle size of the nano metal particles is 10 nm-30 nm. In another possible implementation manner, the thickness of the first functional layer is 20 μm to 30 μm, the thickness of the second functional layer is 4 μm to 6 μm, and the thickness of the third functional layer is 50nm to 200nm. In another aspect, there is provided a method for preparing a negative electrode sheet, the negative electrode sheet being as described in any one of the above, the method comprising: Providing a negative current collector, first slurry corresponding to the first functional layer and second slurry corresponding to the second functional layer; Coating the first slurry on the surface of the negative electrode current collector, and forming the first functional layer on the surface of the negative electrode current collector to obtain a substrate pole piece; Coating the second slurry on the surface of the substrate pole piece, and forming the second functional layer on the surface of the first functional layer to obtain a pre-composite pole piece; and depositing a material corresponding to a third functional layer on the surface of the pre-composite pole piece, and forming the third functional layer on the surface of the second functional layer to obtain the negative pole piece. In another aspect, a solid-state battery is provided, the solid-state battery comprising a solid-state electrolyte, a positive electrode tab and a negative electrode tab disposed on both sides of the solid-state electrolyte, wherein the negative electrode tab is as described in any one of the above. The embodiment of the application provides a negative electrode plate, wherein a third functional layer in the negative electrode plate is used as an electronic insulation-ion conducting layer and is made of an electronic insulation but ion conducting material, so that the transmission of electrons between a negative electrode and a solid electrolyte can be effectively isolated, and side reactions such as decomposition of the solid electrolyte are avoided, and the cycling stabi