CN-122025638-A - Solid electrolyte interface material, preparation method thereof and negative electrode plate

Abstract

The application discloses a solid electrolyte interface material, a preparation method thereof and a negative electrode plate, and belongs to the technical field of secondary batteries. The preparation raw materials of the solid electrolyte interface material comprise a silicon-containing material and a silane coupling agent, wherein the structural formula of the silane coupling agent is shown as formula I: In the formula I, X and Y are respectively and independently methoxy or ethoxy, R 1 is imino or oxyylene, R 2 is any one of substituted or unsubstituted C1-C6 alkylene and substituted or unsubstituted C6-C20 arylene, and R 3 and R 4 are respectively and independently any one of substituted or unsubstituted C1-C6 alkylene. The negative electrode material prepared from the solid electrolyte interface material has good cycle stability and specific capacity.

Inventors

• ZHU XINGBAO
• CHEN KAI
• ZHANG WENQIANG
• LI XIAOLONG
• ZHOU XUEFENG

Assignees

• 合肥国轩高科动力能源有限公司

Dates

Publication Date

20260512

Application Date

20260211

Claims (10)

1. 1. The solid electrolyte interface material is characterized in that the preparation raw materials of the solid electrolyte interface material comprise a silicon-containing material and a silane coupling agent, and the structural formula of the silane coupling agent is shown as formula I: A formula I; In the formula I, X and Y are respectively and independently methoxy or ethoxy, R 1 is imino or oxyylene, R 2 is any one of substituted or unsubstituted C1-C6 alkylene and substituted or unsubstituted C6-C20 arylene, and R 3 and R 4 are respectively and independently any one of substituted or unsubstituted C1-C6 alkylene.
2. 2. The solid electrolyte interface material of claim 1, wherein at least one of the following conditions is satisfied: (1) R 2 is any one of substituted or unsubstituted C2-C4 alkylene and substituted or unsubstituted phenylene; (2) R 3 and R 4 are each independently any one of substituted or unsubstituted C2-C4 alkylene.
3. 3. The solid electrolyte interface material of claim 2, wherein at least one of the following conditions is satisfied: (1) The X and the Y are methoxy; (2) R 2 is any one of unsubstituted C2-C4 alkyl and unsubstituted phenylene; (3) R 3 and R 4 are each independently any one of unsubstituted C2-C4 alkylene groups.
4. 4. The solid electrolyte interface material of claim 3 wherein the silane coupling agent is selected from one or more of the following compounds of formulas II to V: A formula II, A formula III, A formula IV, Formula V.
5. 5. The solid electrolyte interface material of any one of claims 1 to 4 wherein the silicon-containing material comprises at least one of crystalline silicon, amorphous silicon, silicon oxide, a silicon alloy, and a silicon-carbon composite.
6. 6. The solid electrolyte interface material according to claim 5, wherein the mass ratio of the silicon-containing material to the silane coupling agent is 1 (0.01 to 0.5).
7. 7. A method for producing the solid electrolyte interface material according to any one of claims 1 to 6, comprising the steps of: dispersing a silicon-containing material into an organic solvent to obtain a suspension; Adding a silane coupling agent and water into the suspension, and performing condensation reflux treatment to obtain a mixture; And filtering and drying the mixture to obtain the solid electrolyte interface material.
8. 8. The method for producing a solid electrolyte interface material according to claim 7, wherein at least one of the following conditions is satisfied: (1) The organic solvent is at least one selected from toluene, tetrahydrofuran, acetonitrile, dimethylformamide and absolute ethyl alcohol; (2) The mass volume ratio of the silicon-containing material to the organic solvent is 1g (8-15) mL; (3) The mass volume ratio of the silane coupling agent to the water is (3-7) g/1 mL.
9. 9. The method for producing a solid electrolyte interface material according to claim 7 or 8, characterized in that at least one of the following conditions is satisfied: (1) The temperature of the condensation reflux treatment is 60-100 ℃; (2) The time of the condensation reflux treatment is 2-8 hours; (3) The filtering method is centrifugal filtering; (4) The drying is carried out under vacuum condition, and the temperature of the drying is 20-60 ℃.
10. 10. A negative electrode sheet, characterized in that the negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer positioned on at least one side of the negative electrode current collector, the negative electrode active material layer comprises a negative electrode active material, a conductive agent, a binder and a solid electrolyte interface material, and the solid electrolyte interface material is the solid electrolyte interface material according to any one of claims 1 to 6 or the solid electrolyte interface material prepared by the preparation method according to any one of claims 7 to 8.

Description

Solid electrolyte interface material, preparation method thereof and negative electrode plate Technical Field The application relates to the technical field of secondary batteries, in particular to a solid electrolyte interface material, a preparation method thereof and a negative electrode plate. Background With the increasing demands of consumers for high-energy density and high-safety lithium ion batteries, the conventional graphite anode materials cannot meet the demands of consumers. The silicon-based material has extremely high application potential in the lithium ion battery anode material due to high theoretical specific capacity, and the current commercial silicon-based anode material is a composite anode material of graphite and silicon derivatives. Because the silicon derivatives have large volume changes, the structure and interface stability of the anode material are poor, solid Electrolyte Interfaces (SEI) are easy to repeatedly crush and generate in the battery cycle process, and a large amount of electrolyte is consumed, therefore, the silicon content in the composite anode material is often limited to be less than 10%, the specific capacity of the composite anode material is usually less than 650mAh/g, and further pursuing high silicon content and high specific capacity is extremely challenging. Disclosure of Invention The application mainly aims to provide a solid electrolyte interface material, a preparation method thereof and a negative electrode plate, so as to solve the problem that the negative electrode material in the prior art is difficult to have good specific capacity and cycle stability. In order to achieve the above object, according to a first aspect of the present application, there is provided a solid electrolyte interface material, the preparation raw materials of which include a silicon-containing material and a silane coupling agent, wherein the silane coupling agent has a structural formula as shown in formula I: A formula I; In the formula I, X and Y are respectively and independently methoxy or ethoxy, R 1 is imino or oxyylene, R 2 is any one of substituted or unsubstituted C1-C6 alkylene and substituted or unsubstituted C6-C20 arylene, and R 3 and R 4 are respectively and independently any one of substituted or unsubstituted C1-C6 alkylene. In the embodiment of the application, the types of the silane coupling agent are selected, so that a uniform coating layer is formed on the surface of the silicon-containing material, silicon agglomeration in the subsequent slurry mixing process can be effectively prevented, si-OH generated after alkoxy in the silane coupling agent is hydrolyzed can be dehydrated and condensed with hydroxyl on the surface of the silicon-containing material, the binding force between SEI and the silicon-containing material is effectively enhanced, and silicon expansion is inhibited. In addition, the N-H bond can be used as a hydrogen bond donor, and the oxygen atom in C=O can be used as a hydrogen bond acceptor, so that the silane coupling agent has the function of generating a plurality of hydrogen bonds, is favorable for forming a hydrogen bond network in the solid electrolyte interface material, and meanwhile, disulfide bonds in the structure can be complementary with the hydrogen bonds, so that the solid electrolyte interface material is endowed with excellent self-repairing performance, and further the cycle stability of the silicon-based anode material is favorable for being improved. In some embodiments, R 2 is any one of a substituted or unsubstituted C2-C4 alkylene group, a substituted or unsubstituted phenylene group, and R 3 and R 4 are each independently any one of a substituted or unsubstituted C2-C4 alkylene group. The optimization of the type of R 2 ensures that the silane coupling agent and the surface of the silicon-containing material form a stable chemical bond, and meanwhile, the solid electrolyte interface material has certain flexibility, so that the stress in the cathode material in the battery cycle process is relieved, and the cycle life of the silicon-based cathode material is prolonged. The optimization of the types of R 3 and R 4 is helpful for optimizing the binding force between the silane coupling agent and the silicon-containing material, maintaining the ionic conductivity of the solid electrolyte interface material and improving the comprehensive electrochemical performance of the cathode material. Further, R 2 is any one of unsubstituted C2-C4 alkylene and unsubstituted phenylene, and R 3 and R 4 are each independently any one of unsubstituted C2-C4 alkylene. In some embodiments, X and Y are methoxy. The optimization of the types of X and Y is favorable for improving the reactivity of the silane coupling agent and the silicon-containing material, and further favorable for enhancing the modification effect of the silane coupling agent on the silicon-containing material, so that the cycling stability of the anode mate