CN-121983551-A - Negative electrode slurry, composite negative electrode and sulfide all-solid-state battery

Abstract

The invention discloses a cathode slurry, a composite cathode and a sulfide all-solid-state battery, belonging to the technical field of battery materials; according to the invention, the composite negative electrode plate is prepared from the adhesive, the metal particles and the silicon particles, and in the working process of the battery, the metal particles and lithium elements can form lithium-containing alloy, so that the particle diffusion coefficient of lithium ions is enhanced, and the electron conduction capacity and the ion conduction capacity of the silicon-based negative electrode are further improved. The composite negative electrode effectively improves the electronic conductivity and the ionic conductivity of the whole negative electrode, can keep higher capacity play under the conditions of high loading and high current density, and has good multiplying power performance and long-cycle stability.

Inventors

• SONG JIANGXUAN
• Luan Shuyang

Assignees

• 西安交通大学

Dates

Publication Date

20260505

Application Date

20260224

Claims (10)

1. 1. The negative electrode slurry is characterized by comprising silicon particles, metal particles and a binder, wherein the metal particles are simple substance metal particles or alloy particles; In the charging process, the metal particles are used for reacting with lithium ions to generate the lithium-containing alloy.
2. 2. The negative electrode slurry according to claim 1, wherein the mass ratio of the silicon particles, the metal particles and the binder is (40-90): (5-50): (5-15).
3. 3. A negative electrode slurry according to claim 1 or 2, wherein the metal particles comprise at least one or more elements selected from the group consisting of zinc, magnesium, aluminum, indium, tin, silver, copper, gallium and nickel.
4. 4. A negative electrode slurry according to claim 3, characterized in that the metal particles comprise at least one or more elements of zinc, magnesium, aluminum, indium, tin, silver, copper.
5. 5. The anode slurry according to claim 4, wherein the metal particles are elemental metal particles.
6. 6. A negative electrode slurry according to claim 1 or 2, characterized in that the metal particles are nano-, sub-or micro-particles.
7. 7. The negative electrode slurry according to claim 1, wherein the binder is any one or more of polyacrylic acid, polyvinylidene fluoride and sodium alginate.
8. 8. The negative electrode slurry of claim 1, wherein the silicon particles are nano-silicon, sub-micron silicon or micron silicon.
9. 9. A composite anode comprising a current collector and an anode active layer disposed on the current collector, wherein the anode active layer is prepared by drying the anode slurry of claim 1.
10. 10. A sulfide all-solid-state battery comprising a positive electrode, a sulfide solid-state electrolyte layer, and a composite negative electrode according to claim 9, wherein the positive electrode comprises at least lithium element.

Description

Negative electrode slurry, composite negative electrode and sulfide all-solid-state battery Technical Field The invention belongs to the technical field of battery materials, and particularly relates to a negative electrode slurry, a composite negative electrode and a sulfide all-solid-state battery. Background With the continuous improvement of the performance requirements of the energy storage batteries in the civil and military fields, the lithium ion batteries face higher challenges in terms of safety and energy density. However, the organic liquid electrolyte adopted by the current mainstream liquid lithium ion battery system is flammable and explosive, and has obvious potential safety hazard. Meanwhile, the energy density of the material is limited by the intrinsic characteristics of the material of the liquid system, which is close to the theoretical limit, so that the material is difficult to meet the increasing application demands. Therefore, all-solid-state battery systems having both high safety and high energy density potential are important developments. The sulfide all-solid-state battery uses the sulfide solid-state electrolyte which has high thermal stability and is nonflammable to replace the organic liquid electrolyte, so that the safety problem of the battery is essentially solved. By matching the high voltage positive electrode material with the high capacity density negative electrode material, increasing the proportion of active materials, the system exhibits great potential for achieving higher energy density. The performance of the negative electrode material is particularly critical among the key elements of achieving high energy density of the sulfide all-solid state battery. Although the lithium metal anode has the lowest electrochemical potential, the problem of dendrite growth which is difficult to inhibit in the circulation process is extremely easy to cause the internal short circuit failure of the battery, and the bottleneck which has not been effectively overcome so far. Based on the method, the silicon negative electrode is introduced to replace the lithium metal negative electrode, and the pure silicon negative electrode is regarded as an ideal negative electrode material for realizing the high-energy-density all-solid-state battery due to the advantages of ultrahigh theoretical specific capacity, proper low lithium intercalation potential, lower cost and the like. And especially, the pure silicon negative electrode is introduced into a sulfide all-solid-state battery system, so that the energy density of the battery can be remarkably improved. However, the silicon material is a semiconductor, and has low intrinsic electronic conductivity and ionic conductivity, so that the capacity exertion under high load and high current density is restricted, and the challenges in the aspect of conductivity severely restrict the practical application of the pure silicon cathode in the sulfide all-solid-state battery. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a negative electrode slurry, a composite negative electrode and a sulfide all-solid-state battery, so as to solve the problem that capacity is difficult to develop under high load and high current density when a silicon material is applied to the negative electrode material of the sulfide all-solid-state battery in the prior art. In order to achieve the purpose, the invention is realized by adopting the following technical scheme: the negative electrode slurry comprises silicon particles, metal particles and a binder, wherein the metal particles are simple substance metal particles or alloy particles; In the charging process, the metal particles are used for reacting with lithium ions to generate the lithium-containing alloy. The invention further improves that: preferably, the mass ratio of the silicon particles to the metal particles to the binder is (40-90)/(5-50)/(5-15). Preferably, the metal particles comprise at least one or more elements selected from zinc, magnesium, aluminum, indium, tin, silver, copper, gallium and nickel. Preferably, the metal particles comprise at least one or more elements selected from zinc, magnesium, aluminum, indium, tin, silver, and copper. Preferably, the metal particles are elemental metal particles. Preferably, the metal particles are nanoparticles, submicron particles or microparticles. Preferably, the adhesive is any one or more of polyacrylic acid, polyvinylidene fluoride or sodium alginate. Preferably, the silicon particles are nano-silicon, sub-micron silicon or micron silicon. The composite anode comprises a current collector and an anode active layer arranged on the current collector, wherein the anode active layer is prepared by drying the anode slurry. A sulfide all-solid-state battery comprises a positive electrode, a sulfide solid-state electrolyte layer and one of the composite negative electrodes, wherein the positive electrode