CN-121983644-A - Flame-retardant composite solid electrolyte and preparation method and application thereof

CN121983644ACN 121983644 ACN121983644 ACN 121983644ACN-121983644-A

Abstract

The invention relates to the technical field of solid-state batteries, in particular to a flame-retardant composite solid-state electrolyte, a preparation method and application thereof, wherein the preparation method of the flame-retardant composite solid-state electrolyte comprises the steps of mixing carbonate polymer monomers, amide group-containing polymer monomers and lithium salt to obtain a monomer solution; mixing the monomer solution with inorganic electrolyte and initiator to obtain composite electrolyte precursor solution, loading the composite electrolyte precursor solution on polyimide porous membrane, and curing in situ to obtain the flame-retardant composite solid electrolyte. The polyimide porous membrane is used as a matrix, an organic network is formed by copolymerization of a carbonate polymer monomer and a polymer monomer containing an amide group, organic-inorganic synergistic flame retardance is realized by compounding lithium salt serving as lithium ion transmission with an inorganic oxide solid electrolyte, and the inorganic electrolyte and a polymer chain form a three-dimensional framework structure and are anchored by oxygen vacancies to form a stable composite system.

Inventors

WANG JUN
YU KAI
XU XIAOXIONG
CHI SHANGSEN
DENG YONGHONG
Wei Zhenyao

Assignees

南方科技大学

Dates

Publication Date: 20260505
Application Date: 20260108

Claims (10)

1. The preparation method of the flame-retardant composite solid electrolyte is characterized by comprising the following steps: Mixing a carbonate type polymerization monomer, an amide group-containing polymerization monomer and lithium salt to obtain a monomer solution; mixing the monomer solution with an inorganic electrolyte and an initiator to obtain a composite electrolyte precursor solution; And loading the composite electrolyte precursor solution on a polyimide porous membrane, and performing in-situ curing treatment to obtain the flame-retardant composite solid electrolyte.
2. The method for preparing the flame-retardant composite solid electrolyte according to claim 1, wherein the carbonic ester type polymer monomer is one or more selected from vinylene carbonate, vinyl ethylene carbonate and methyl acrylate, and the amide group-containing polymer monomer is one or more selected from N, N' -methylenebisacrylamide, N-vinylformamide and methacrylamide.
3. The method for preparing a flame retardant composite solid electrolyte according to claim 1, wherein the lithium salt is one or more selected from the group consisting of lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis (difluorosulfonimide), lithium bis (trifluoromethylsulfonimide), lithium bis (oxalato) borate, and lithium difluorooxalato borate.
4. The method of preparing a flame retardant composite solid electrolyte according to claim 1, wherein the inorganic electrolyte comprises one of an inorganic oxide electrolyte, a sulfide electrolyte, and a halide electrolyte; preferably, the inorganic oxide electrolyte is selected from one or more of NASICON type electrolyte, perovskite type electrolyte, garnet type electrolyte and LISIICON type electrolyte, and the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptonitrile and benzoyl peroxide.
5. The method for producing a flame-retardant composite solid electrolyte according to claim 1, wherein the molar ratio of the carbonate-based polymer monomer to the amide group-containing polymer monomer is (1-50): 1, and the molar fraction of the lithium salt in the monomer solution is 0.1mol/L to 4mol/L.
6. The method for preparing a flame retardant composite solid electrolyte according to claim 1, wherein the addition amount of the inorganic electrolyte is 1% -80% of the total mass of the composite electrolyte precursor solution.
7. The method for preparing a flame retardant composite solid electrolyte according to claim 1, wherein the initiator is added in an amount of 0.01% -1% of the total mass of the composite electrolyte precursor solution.
8. The method for preparing a flame retardant composite solid electrolyte according to claim 1, wherein the temperature of the in-situ curing treatment is 30 ℃ to 100 ℃, and the time of the in-situ curing treatment is 1h to 24h.
9. A flame retardant composite solid electrolyte prepared by the method of preparing a flame retardant composite solid electrolyte according to any one of claims 1 to 8.
10. Use of the flame retardant composite solid state electrolyte of claim 9 in an all solid state lithium metal battery.

Description

Flame-retardant composite solid electrolyte and preparation method and application thereof Technical Field The invention relates to the technical field of solid-state batteries, in particular to a flame-retardant composite solid-state electrolyte, and a preparation method and application thereof. Background The traditional liquid lithium ion battery has the safety accident frequently caused by the inflammable electrolyte, the thermal runaway temperature is lower than 100 ℃, and the combustion risk can be fundamentally eliminated by replacing a liquid system with a solid electrolyte, but the commercialization of the all-solid-state battery has two main challenges that the inorganic electrolyte has high brittleness and high interface impedance, the polymer electrolyte has low room temperature conductivity and inflammability, so that the safety is insufficient, and the traditional flame retardant is easy to cause interface side reaction and cannot inhibit the thermal runaway chain reaction, so that the flame retardant performance is lost. The existing flame-retardant solid electrolyte technology has obvious defects: 1. The inorganic flame retardant additive (such as silicon dioxide, aluminum oxide and the like) is only used for physically isolating and inhibiting combustion, and cannot block free radical combustion chain reaction, so that the flame retardant effect is general, the quality of more inactive substances can be increased, and the energy density of the battery is reduced; 2. Inherently flame retardant polymers (e.g., polyphosphazenes) are complex to synthesize, costly (> 500 dollars/kg), and have insufficient room temperature conductivity (< 10 -5 S/cm), limited in practical applications; 3. the flame retardant coating electrolyte has poor coating effect, the coating layer is easy to crack and fail, and the multi-step process is difficult to be applied in large-scale industrialization. Accordingly, the prior art is still in need of improvement and development. Disclosure of Invention In view of the defects in the prior art, the invention aims to provide a flame-retardant composite solid electrolyte, a preparation method and application thereof, and aims to solve the problems of insufficient ion conductivity and defects in flame retardant performance of the conventional solid electrolyte. The technical scheme of the invention is as follows: a preparation method of a flame-retardant composite solid electrolyte comprises the following steps: Mixing a carbonate type polymerization monomer, an amide group-containing polymerization monomer and lithium salt to obtain a monomer solution; mixing the monomer solution with an inorganic electrolyte and an initiator to obtain a composite electrolyte precursor solution; And loading the composite electrolyte precursor solution on a polyimide porous membrane, and performing in-situ curing treatment to obtain the flame-retardant composite solid electrolyte. The preparation method of the flame-retardant composite solid electrolyte comprises the steps that the carbonic ester type polymer monomer is selected from one or more of ethylene carbonate, ethylene vinyl carbonate and methyl acrylate, and the amide group-containing polymer monomer is selected from one or more of N, N' -methylene bisacrylamide, N-vinyl formamide and methacrylamide. The preparation method of the flame-retardant composite solid electrolyte comprises the step of preparing a flame-retardant composite solid electrolyte, wherein the lithium salt is one or more selected from lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis (difluoro) sulfonimide, lithium bis (trifluoromethyl) sulfonimide, lithium bis (oxalato) borate and lithium difluoro (oxalato) borate. The preparation method of the flame-retardant composite solid electrolyte comprises the step of preparing the flame-retardant composite solid electrolyte, wherein the inorganic electrolyte comprises one of inorganic oxide electrolyte, sulfide electrolyte and halide electrolyte; preferably, the inorganic oxide electrolyte is selected from one or more of NASICON type electrolyte, perovskite type electrolyte, garnet type electrolyte and LISIICON type electrolyte, and the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptonitrile and benzoyl peroxide. The preparation method of the flame-retardant composite solid electrolyte comprises the steps of (1-50) enabling the molar ratio of the carbonate polymer monomer to the amide group-containing polymer monomer to be 1, and enabling the molar fraction of the lithium salt in the monomer solution to be 0.1-4 mol/L. The preparation method of the flame-retardant composite solid electrolyte comprises the step of adding the inorganic electrolyte in an amount which is 1-80% of the total mass of the composite electrolyte precursor solution. The preparation method of the flame-retardant composite solid electrolyte comprises the step of adding th