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CN-122025542-A - Negative electrode plate and preparation method and application thereof

CN122025542ACN 122025542 ACN122025542 ACN 122025542ACN-122025542-A

Abstract

The invention relates to the technical field of solid lithium ion battery electrode materials, in particular to a negative electrode plate and a preparation method and application thereof. The first lamination structure of the negative electrode plate comprises a current collector, an amorphous carbon material layer, a metal lithium layer, a silicon material layer and a lithium alloy layer which are sequentially laminated, and the second lamination structure comprises the current collector, the metal lithium layer, the amorphous carbon material layer, the silicon material layer and the lithium alloy layer which are sequentially laminated. According to the negative electrode plate, by providing two equivalent lamination structure arrangement modes, the amorphous carbon layer is used as a buffer matrix, the metal lithium layer compensates irreversible capacity, the silicon layer is used as a capacity main body, the lithium alloy layer is used as an interface stabilizing and dendrite resisting functional layer, and the partition synergy and interface stress regulation and control of each functional component are realized, so that the whole volume expansion of the electrode is obviously inhibited, the first-week coulomb efficiency is improved, the growth of lithium dendrite is effectively prevented, and the structural stability and the cycle life of the negative electrode are enhanced while the high specific capacity is ensured.

Inventors

  • WEI SAIQI
  • ZHAI XIMIN
  • LOU SHUAIFENG
  • WANG QI
  • SUN XUEYING
  • NING YANBIN
  • SUN HUANLI
  • YANG FENG

Assignees

  • 中国第一汽车股份有限公司
  • 哈尔滨工业大学

Dates

Publication Date
20260512
Application Date
20260302

Claims (10)

  1. 1. The negative electrode plate is characterized by comprising a first laminated structure or a second laminated structure: the first lamination structure comprises a current collector, an amorphous carbon material layer, a metal lithium layer, a silicon material layer and a lithium alloy layer which are sequentially laminated; The second lamination structure comprises the current collector, the metal lithium layer, the amorphous carbon material layer, the silicon material layer and the lithium alloy layer which are sequentially laminated.
  2. 2. The negative electrode tab of claim 1, wherein the amorphous carbon material layer comprises amorphous carbon, a doping material, and a binder.
  3. 3. The negative electrode tab of claim 2, wherein the doping material comprises carbon nanotubes or silicon; Preferably, the mass ratio of the amorphous carbon, the carbon nano tube and the binder is 80-89:1-10:10; preferably, the mass ratio of the amorphous carbon, the silicon and the binder is 45-55:45-55:10.
  4. 4. The negative electrode tab of claim 1, wherein the amorphous carbon material layer has a thickness of 15-25 μm.
  5. 5. The negative electrode tab of claim 1, wherein the metallic lithium layer has a thickness of 5-8 μm.
  6. 6. The negative electrode plate according to claim 2, wherein the silicon material layer comprises silicon powder, carbon nanotubes and the binder in a mass ratio of 75-85:5-15:10.
  7. 7. The negative electrode tab of claim 1, wherein the silicon material layer has a thickness of 10-15 μm.
  8. 8. The negative electrode tab of claim 1, wherein the lithium alloy layer comprises at least one of a lithium tin alloy, a lithium indium alloy, or a lithium aluminum alloy; and/or the thickness of the lithium alloy layer is 3-5 mu m.
  9. 9. A method for producing the negative electrode sheet according to any one of claims 1 to 8, comprising the steps of: The respective structural layers are combined in the lamination order of the first lamination structure or the second lamination structure.
  10. 10. A solid-state battery comprising the negative electrode tab of any one of claims 1 to 8.

Description

Negative electrode plate and preparation method and application thereof Technical Field The invention relates to the technical field of solid lithium ion battery electrode materials, in particular to a negative electrode plate and a preparation method and application thereof. Background With the rapid development of electric vehicles and energy storage technologies, the demand for batteries with high energy density and high safety is increasingly urgent. Solid-state batteries are considered as an important direction of the next-generation battery technology because of the advantages of high energy density, good safety, long cycle life and the like due to the fact that the solid electrolyte is adopted to replace the traditional liquid electrolyte. In solid state batteries, the choice of the negative electrode material directly affects the overall performance of the battery, especially the energy density, cycling stability and safety. Currently, research on solid-state battery anode materials is mainly focused on three types of materials, silicon-based, carbon-based and lithium-based. Silicon materials are widely focused because of the theoretical specific capacity of up to 4200mAh/g, but the volume expansion exceeding 300% in the lithium intercalation and deintercalation process is easy to cause electrode structure damage and interface failure, carbon-based materials (such as graphite) have stable structures and good conductivity, but the theoretical specific capacity is only 372mAh/g, the requirement of high energy density is difficult to meet, and metallic lithium has extremely high theoretical specific capacity (3860 mAh/g) and low electrode potential, but lithium dendrites are easy to form in the circulation process, and potential safety hazards of short circuit caused by electrolyte penetration exist. In order to achieve both high capacity and structural stability, researchers have attempted to combine silicon with carbon or lithium to form silicon/carbon or silicon/lithium composite cathodes. However, most of the existing composite structures are simple double-layer or non-gradient designs, and lack of effective stress matching and interface regulation among the components, so that the problems of volume expansion of silicon, dendrite growth of lithium and interface compatibility among materials cannot be solved at the same time. In addition, the existing composite negative electrode has complex preparation process and poor compatibility with large-scale production equipment, and restricts the industrialization process. Therefore, developing a composite negative electrode material capable of cooperatively realizing high capacity, low expansion, dendrite resistance and good interface stability, and having process suitability and large-scale production potential becomes a key problem to be solved in the field of solid-state battery negative electrode materials. In view of this, the present invention has been made. Disclosure of Invention Aiming at the defects of the existing solid-state battery anode material in the aspects of capacity, structural stability, interface compatibility, process suitability and the like, the invention provides an anode piece, a preparation method and application thereof. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: The invention relates to a negative electrode plate, which comprises a first laminated structure or a second laminated structure, wherein the first laminated structure comprises a current collector, an amorphous carbon material layer, a metal lithium layer, a silicon material layer and a lithium alloy layer which are laminated in sequence, and the second laminated structure comprises the current collector, the metal lithium layer, the amorphous carbon material layer, the silicon material layer and the lithium alloy layer which are laminated in sequence. According to the negative electrode plate, by providing two equivalent lamination structure arrangement modes, an amorphous carbon layer is used as a buffer matrix, a metal lithium layer compensates irreversible capacity, a silicon layer is used as a capacity main body, a lithium alloy layer is used as an interface stabilization and dendrite resistance functional layer, and the partition coordination and interface stress regulation of each functional component are realized, so that the high specific capacity is ensured, the overall volume expansion of the electrode is obviously inhibited, the first-week coulomb efficiency is improved, the growth of lithium dendrite is effectively prevented, and the structural stability and the cycle life of the negative electrode in a solid-state battery system are enhanced. The invention also relates to a preparation method of the negative electrode plate, which comprises the following steps of compositing the structural layers according to the lamination sequence of the first lamination structure or the