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CN-122025644-A - Lithium ion battery additive, preparation method thereof, positive electrode slurry, positive electrode plate and lithium battery

CN122025644ACN 122025644 ACN122025644 ACN 122025644ACN-122025644-A

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery additive, a preparation method thereof, positive electrode slurry, a positive electrode plate and a lithium battery. The preparation raw materials comprise, by weight, 10-20% of a first dispersing agent, 5-15% of a second dispersing agent, 5-15% of a stabilizing agent, 1% of a defoaming agent and the balance of a solvent, wherein the first dispersing agent is a C 6 -C 16 phosphate compound containing at least one acidic hydroxyl group, and the second dispersing agent comprises at least one of polyetheramine with a number average molecular weight of 2000-4000 and polyethyleneimine ethoxylate with a number average molecular weight of 10000-15000. The lithium ion battery additive for the lithium-supplementing agent system prepared by adopting specific raw material selection can not only effectively solve the problems of low solid content, easy gelation and poor stability of the positive electrode slurry of the lithium-supplementing agent system, but also reduce the resistance of a pole piece, reduce the polarization of the battery and improve the capacity of the lithium-supplementing agent.

Inventors

  • Geng Yuekai
  • JING XIWEI
  • HAO RUIWEN
  • QI WENGANG
  • WANG ZHENGZHENG

Assignees

  • 江苏一特新材料股份有限公司

Dates

Publication Date
20260512
Application Date
20260416

Claims (10)

  1. 1. The lithium ion battery additive is characterized by comprising, by weight, 10-20% of a first dispersing agent, 5-15% of a second dispersing agent, 5-15% of a stabilizing agent, 1% of a defoaming agent and the balance of a solvent; The first dispersing agent is a C 6 -C 16 phosphate compound containing at least one acidic hydroxyl group; The second dispersant comprises at least one of polyetheramine with a number average molecular weight of 2000-4000 and polyethyleneimine ethoxylate with a number average molecular weight of 10000-15000.
  2. 2. The lithium ion battery additive of claim 1, wherein the first dispersant comprises at least one of nonylphenol polyoxyethylene ether phosphate, dinonylphenol polyoxyethylene ether phosphate, octylphenol polyoxyethylene ether phosphate, isomeric tridecyl alcohol phosphate, dodecyl polyoxyethylene ether phosphate, isomeric dodecyl alcohol polyoxyethylene ether phosphate, isomeric dodecyl alcohol phosphate, isomeric diisooctyl phosphate, di-n-octyl phosphate, isooctyl alcohol phosphate, dihexyl phosphate.
  3. 3. The lithium ion battery additive according to claim 1, wherein the stabilizer is a hydrazine compound.
  4. 4. The lithium ion battery additive according to claim 3, wherein the hydrazine compound comprises at least one of phenylhydrazine, acetylhydrazine, acethydrazide, ohydrazide, methyl hydrazineformate, hydrazinoethanol, adipic acid dihydrazide.
  5. 5. The lithium ion battery additive of claim 1, wherein the defoamer comprises a fatty alcohol.
  6. 6. The lithium ion battery additive of claim 5, wherein the fatty alcohol comprises at least one of isopropanolamine, 1, 3-butanediol, 1, 4-butanediol, 1, 2-propanediol, 1, 3-propanediol, 2-amino-2 methyl-1-propanol.
  7. 7. A method of preparing a lithium ion battery additive according to any one of claims 1-6, comprising at least the steps of: And heating and dissolving the solvent, the first dispersing agent and the second dispersing agent under the protection of inert atmosphere, cooling to below 40 ℃, adding the stabilizing agent and the defoaming agent, and continuously stirring to obtain the lithium ion battery additive.
  8. 8. A positive electrode slurry, wherein the preparation raw material comprises the lithium ion battery additive according to any one of claims 1 to 6, or the lithium ion battery additive prepared by the preparation method according to claim 7.
  9. 9. A positive electrode sheet comprising a positive electrode current collector, the surface of which is coated with the positive electrode slurry according to claim 8.
  10. 10. A lithium battery comprising the positive electrode sheet according to claim 9.

Description

Lithium ion battery additive, preparation method thereof, positive electrode slurry, positive electrode plate and lithium battery Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery additive, a preparation method thereof, positive electrode slurry, a positive electrode plate and a lithium battery. Background With the rapid development of electric vehicles and electrochemical energy storage, conventional lithium ion battery systems have difficulty meeting the increasing energy density requirements. In practical application, only improving the energy density of the positive electrode has limited effect on the whole battery, because the negative electrode consumes a large amount of active lithium ions when forming a solid electrolyte interface in the first cycle, and reduces the energy density of the whole battery. Therefore, the development of the positive electrode lithium supplementing technology to supplement the active lithium loss of the negative electrode is important to the construction of the next-generation high-specific-energy lithium ion battery. The sacrificial positive electrode lithium supplementing agent is widely researched in academia and industry by virtue of the characteristics of in-situ addition, high stability and safety. The lithium-rich metal oxide such as Li 5FeO4、Li6CoO4、Li2NiO2、Li5MnO4 has higher lithium supplementing capacity and moderate working voltage, can compensate lithium loss in the process of charging and discharging to a great extent, and for example, the Chinese patent application CN115425279A provides a sacrificial positive electrode lithium supplementing additive and a preparation method thereof, but the problems of unstable surface residual alkali content, large polarization, abnormal gas production caused by side reaction with electrolyte, easy oxidation in air, lithium hydroxide caused by reaction with water in air, gelation of slurry in the process of coating positive electrode materials caused by the excessive content of lithium hydroxide, incapability of coating and the like exist, and the large-scale application of the lithium-ion battery is limited. Therefore, there is an urgent need to develop a new lithium ion battery additive for a lithium-supplementing agent system, which solves the problem of poor stability of the positive electrode slurry of the lithium-supplementing agent system. Disclosure of Invention In order to solve the technical problems, the first aspect of the invention provides a lithium ion battery additive, which comprises, by weight, 10-20% of a first dispersing agent, 5-15% of a second dispersing agent, 5-15% of a stabilizing agent, 1% of a defoaming agent and the balance of a solvent; The first dispersing agent is a C 6-C16 phosphate compound containing at least one acidic hydroxyl group; The second dispersant comprises at least one of polyetheramine with a number average molecular weight of 2000-4000 and polyethyleneimine ethoxylate with a number average molecular weight of 10000-15000. The current lithium supplementing additive is easy to cause the gel phenomenon of slurry in actual use, and the normal use of the slurry is affected. The invention selects long-chain phosphate with a specific structure, the phosphate group is anionic groups and can be effectively adsorbed on the surfaces of positive electrode active substances, conductive agents and lithium supplementing agent particles to form an electrostatic repulsive layer, agglomeration among the particles is prevented, a protective layer is formed on the outer layer of the lithium supplementing agent particles, the reaction of the inner core of the lithium supplementing agent with moisture and carbon dioxide can be effectively isolated, the problem of poor air stability of the lithium supplementing agent is solved, in addition, the outer coating layer has good conductivity, the resistivity of the lithium supplementing agent can be effectively reduced, a more excellent lithium supplementing effect is exerted, the long chain generates a steric hindrance effect in a solution, the particles are uniformly dispersed, secondary agglomeration is prevented, the moisture and the particles are isolated by the hydrophobic groups, the deterioration of materials is delayed, and the anti-gel effect is achieved, in addition, the introduction of acidic hydroxyl groups can neutralize residual alkali on the surfaces of the lithium supplementing agent, the carbon reduction reaction caused by a CVD method is effectively blocked, PVDF is also protected from alkaline hydrolysis crosslinking in an overbased environment, and the structure is destroyed, so that the slurry is unstable. The second dispersant is an N-containing polyether copolymer, wherein the hydrophilic and lipophilic groups of the polyether segments can form effective steric hindrance and prevent particles from settling, and the hydroxyl groups and the amino groups form w