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CN-122000469-A - Thermal response interface passivating agent composition, electrolyte and lithium ion battery

CN122000469ACN 122000469 ACN122000469 ACN 122000469ACN-122000469-A

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a thermal response interface passivating agent composition, electrolyte and a lithium ion battery. The thermal response interface passivating agent composition comprises a silane component and a sulfur system component, wherein the silane component is selected from any one or more of 3-mercaptopropyl trimethoxy silane, gamma-aminopropyl triethoxy silane or gamma-methacryloxypropyl trimethoxy silane, and the sulfur system component is selected from diisopropyl xanthogenate disulfide and/or diphenyl disulfide. The thermal response interface passivating agent composition provided by the invention does not influence the electrochemical performance of the battery under the conventional running condition of the battery, and can spontaneously polymerize on the surface of the negative electrode to form a stable and compact passivating layer at the high temperature of 100-120 ℃, namely an effective thermal barrier is formed before the rupture of the diaphragm, so that the electron leakage and the decomposition of electrolyte are effectively blocked, and the thermal safety of the battery is obviously improved.

Inventors

  • WU CHUANPING
  • ZHAO YALI
  • LIU YUTAO
  • WANG JIANGFENG
  • Chen kuo
  • CHEN BAOHUI

Assignees

  • 国网湖南省电力有限公司防灾减灾中心
  • 国网湖南省电力有限公司
  • 国家电网有限公司

Dates

Publication Date
20260508
Application Date
20260205

Claims (10)

  1. 1. A thermally responsive interface deactivator composition comprising a silane-based component and a sulfur-based component; the silane component is selected from any one or more of 3-mercaptopropyl trimethoxy silane, gamma-aminopropyl triethoxy silane or gamma-methacryloxypropyl trimethoxy silane; The sulfur component is selected from diisopropyl xanthogen disulfide and/or diphenyl disulfide.
  2. 2. The thermally responsive interface passivation composition of claim 1, wherein the mass ratio of the silane-based component to the sulfur-based component is 1 (0.5-2).
  3. 3. The thermally responsive interface passivation composition of claim 1 or 2, wherein the silane-based component is selected from the group consisting of gamma-aminopropyl triethoxysilane; and/or the thio component is selected from diisopropyl xanthogenate disulfide.
  4. 4. An electrolyte comprising the thermally responsive interface passivation composition of any one of claims 1-3.
  5. 5. Electrolyte according to claim 4, characterized in that the thermally responsive interface passivating agent composition is present in an amount of 1-4%, preferably 2.5-4%, based on 100% of the total mass of the electrolyte.
  6. 6. The electrolyte of claim 4 or 5, wherein the electrolyte further comprises a lithium salt, an additive, and a carbonate-based organic solvent.
  7. 7. The electrolyte according to claim 6, wherein the carbonate-based organic solvent is selected from any one or more of ethylene carbonate, ethylmethyl carbonate, dimethyl carbonate, and diethyl carbonate; and/or the content of the carbonate organic solvent is 77-84% based on 100% of the total mass of the electrolyte.
  8. 8. The electrolyte according to claim 6 or 7, wherein the additive is selected from any one or more of vinylene carbonate, fluoroethylene carbonate, lithium difluorophosphate, vinyl sulfate or lithium difluorooxalato borate; and/or the content of the additive is 2-5% based on 100% of the total mass of the electrolyte.
  9. 9. Electrolyte according to any one of claims 6 to 8, characterized in that the lithium salt is selected from lithium hexafluorophosphate and/or lithium bis-fluorosulfonyl imide; and/or the content of the lithium salt is 9-16% based on 100% of the total mass of the electrolyte.
  10. 10. A lithium ion battery comprising the thermally responsive interface passivating agent composition of any one of claims 1-3 or the electrolyte of any one of claims 4-9.

Description

Thermal response interface passivating agent composition, electrolyte and lithium ion battery Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a thermal response interface passivating agent composition, electrolyte and a lithium ion battery. Background Lithium ion batteries are widely used in the fields of electric automobiles, energy storage, consumer electronics and the like due to high energy density and long cycle life. However, as energy density continues to increase, battery safety issues become more pronounced. Especially, the battery cell is easy to induce chain exothermic reaction inside the battery under extreme thermal, electric and mechanical factors to cause thermal runaway of the battery, and finally fires and even explosions are caused. The existing electrolyte is based on a carbonate system, has low flash point and poor thermal stability, and is one of important causes of thermal runaway chain reaction. The existing lithium ion battery thermal safety protection technology is mainly realized through a high flash point solvent, a flame retardant additive or a gelled electrolyte and other approaches, wherein the thermal response additive has the functions of environmental perception and interface regulation and control. The material can block electrode side reaction through spontaneous polymerization or film formation under high temperature condition, thereby inhibiting thermal runaway chain reaction. However, the conventional thermal response additive has the defects that firstly, the response temperature is too high, the polymerization reaction temperature of typical silane, benzoxazole and phosphorus-containing self-polymerization additives is generally higher than 150 ℃, and the melting fracture temperature of a commercial polyolefin diaphragm is only about 120 ℃, so that the thermal response is delayed to the failure of the diaphragm, secondly, the film forming quality is poor, the interface polymerization is not uniform due to the insufficient dispersion of electrolyte, a passivation layer with a loose structure is formed by partial additive, and the electron conduction cannot be effectively blocked, thirdly, the system compatibility is poor, the high-reactivity additive is easy to generate side reaction with the surface of lithium salt or an electrode, and the electrochemical performance is degraded at normal temperature. It is therefore desirable to provide a new thermally responsive additive and electrolyte. Disclosure of Invention In order to solve the technical problems, the invention provides a thermally responsive interface passivating agent composition, electrolyte and a lithium ion battery. The thermal response interface passivating agent composition provided by the invention does not influence the electrochemical performance of the battery under the conventional running condition of the battery, and can spontaneously polymerize on the surface of the negative electrode to form a stable and compact passivating layer at the high temperature of 100-120 ℃, namely an effective thermal barrier is formed before the rupture of the diaphragm, so that the electron leakage and the decomposition of electrolyte are effectively blocked, and the thermal safety of the battery is obviously improved. In a first aspect, the present invention provides a thermally responsive interface deactivator composition comprising a silane-based component and a sulfur-based component; the silane component is selected from any one or more of 3-mercaptopropyl trimethoxy silane, gamma-aminopropyl triethoxy silane or gamma-methacryloxypropyl trimethoxy silane; The sulfur component is selected from diisopropyl xanthogen disulfide and/or diphenyl disulfide. The thermal response interface passivating agent composition provided by the invention comprises silane components and a sulfur system component, has the condensation polymerization film forming capability of silane molecules and the low-temperature free radical induction characteristic of sulfur system compounds, is applied to electrolyte without influencing the electrochemical performance of a battery under the normal running condition of the battery, and forms a stable and compact passivation layer on the surface of a negative electrode through the synergistic effect of the silane components and the silane components through a free radical induction polymerization mechanism under the high temperature of 100-120 ℃, thereby realizing rapid interface passivation under the low response temperature, inhibiting the decomposition and HF generation of the electrolyte, preventing the thermal runaway of the battery, remarkably reducing the response temperature (30-50 ℃ in advance) compared with the traditional additive, being far lower than the melting threshold of a diaphragm, and overcoming the problems of high response temperature, slow film forming rate, insufficient interface stability and the like of the traditi