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CN-122025770-A - Tough solid polymer electrolyte membrane and preparation method and application thereof

CN122025770ACN 122025770 ACN122025770 ACN 122025770ACN-122025770-A

Abstract

The invention discloses a tough solid polymer electrolyte membrane and a preparation method and application thereof, wherein the tough solid polymer electrolyte membrane comprises a polyvinylidene fluoride matrix, and poly (2-cyano-p-phenylene terephthalamide) and lithium salt which are dispersed in the polyvinylidene fluoride matrix, wherein the mass ratio of the poly (2-cyano-p-phenylene terephthalamide) to the polyvinylidene fluoride matrix is 5% -15%. The solid polymer electrolyte membrane aims to solve the technical problems of low ionic conductivity, poor mechanical property and unstable electrolyte/electrode interface of the existing polyvinylidene fluoride solid polymer electrolyte membrane, and the tough solid polymer electrolyte membrane has high mechanical property, high ionic conductivity and wide electrochemical stability window.

Inventors

  • WU DINGCAI
  • ZHENG LINYING
  • LU YUHENG

Assignees

  • 中山大学

Dates

Publication Date
20260512
Application Date
20251223

Claims (10)

  1. 1. A tough solid polymer electrolyte membrane is characterized by comprising a polyvinylidene fluoride matrix, and poly (2-cyano-p-phenylene terephthalamide) and lithium salt dispersed in the polyvinylidene fluoride matrix, wherein the mass ratio of the poly (2-cyano-p-phenylene terephthalamide) to the polyvinylidene fluoride matrix is 5% -15%.
  2. 2. The tough solid polymer electrolyte membrane according to claim 1, characterized in that the intrinsic viscosity of the poly (2-cyano-paraphenylene terephthalamide) is 1.5 to 8.0 dL/g, and/or the tough solid polymer electrolyte membrane has a thickness of 20 to 30 μm.
  3. 3. A method of making the tough solid polymer electrolyte membrane according to claim 1 comprising: dispersing 2, 5-diaminobenzonitrile and a neutralizing agent in an organic solvent under the condition of inert low temperature to obtain a2, 5-diaminobenzonitrile solution; adding a polybasic acyl chloride monomer into the 2, 5-diaminobenzonitrile solution in batches, standing at room temperature, and regulating to be neutral by using a neutralizing agent; treating the polymer with deionized water and methanol to adjust to a neutral system, precipitating the polymer, carrying out suction filtration, collecting a solid phase, washing and drying to obtain poly (2-cyano-p-phenylene terephthalamide); and mixing the poly (2-cyano-p-phenylene terephthalamide), polyvinylidene fluoride and lithium salt in a solvent to obtain a blending system, and volatilizing the solvent to form a film to obtain the tough solid polymer electrolyte membrane.
  4. 4. The method according to claim 3, wherein the inert low temperature is at a temperature of 0-2 ℃ under an inert atmosphere, and/or the neutralizing agent is one or more of lithium carbonate, calcium carbonate and lithium hydroxide, and/or the polybasic acyl chloride monomer is phthaloyl chloride.
  5. 5. The method according to claim 3, wherein the mass ratio of the 2, 5-diaminobenzonitrile to the polybasic acyl chloride monomer is 5 (7-8).
  6. 6. The method according to claim 3, wherein the step of adding the polybasic acyl chloride monomer in batches comprises dividing the polybasic acyl chloride monomer into two parts according to mass average, adding the first part of polybasic acyl chloride monomer into the 2, 5-diaminobenzonitrile solution, and adding the second part of polybasic acyl chloride monomer at intervals of 1-2 minutes.
  7. 7. The method according to claim 3, wherein the mass ratio of the poly (2-cyano-paraphenylene terephthalamide), polyvinylidene fluoride and lithium salt is (1-3) 20:16.
  8. 8. The method according to claim 3, wherein the step of volatilizing the solvent to form a film comprises dripping the blend onto a glass plate, doctor-blading the blend at room temperature to form a film, and drying the film to obtain the tough solid polymer electrolyte film.
  9. 9. The method according to claim 8, wherein the thickness of the obtained tough solid polymer electrolyte membrane is 20-30 μm, and the doctor blade speed is controlled to be 5-20 mm/s.
  10. 10. Use of the tough solid polymer electrolyte membrane according to claim 1 in lithium metal batteries.

Description

Tough solid polymer electrolyte membrane and preparation method and application thereof Technical Field The invention belongs to the technical field of lithium metal batteries, and particularly relates to a tough solid polymer electrolyte membrane, a preparation method and application thereof. Background Compared with the traditional liquid organic electrolyte, the solid electrolyte has good thermal stability and is nonflammable, can effectively avoid the problems of liquid leakage, fire and the like, and has obviously improved safety. Among them, solid polymer electrolyte membranes are attracting attention by virtue of their light weight, low cost, good flexibility, easy processing, and the like. The solid polymer electrolyte membrane is generally composed of a polymer matrix (such as PVDF, PEO, PMMA, PAN and the like) and lithium salt (such as LiTFSI, liClO 4), but due to the limitation of a polymer molecular structure, the room-temperature ion conductivity and the mechanical strength of most polymer electrolytes are low, and the corresponding lithium metal batteries are difficult to meet the industrial electrochemical performance requirements. In the prior art, functional fillers such as inorganic fillers SiO 2、Al2O3 or LLZO are generally introduced into a polymer matrix, and lithium ion transmission is guided by constructing an organic-inorganic interface, a solid polymer electrolyte membrane added with the inorganic fillers has enhanced mechanical properties and can resist the growth of lithium dendrites, or porous organic fillers (such as COFs or MOFs) are added, so that ion high-speed selective conduction is realized through regular pore channels, interface contact is improved to a certain extent, interface impedance is reduced, and lithium ion transmission is accelerated. However, the filler and the polymer matrix have the defects of poor interfacial compatibility, uneven distribution of lithium ion flow, incapability of effectively inhibiting growth of lithium dendrites and the like. Patent application 201910024056.3 discloses a technical solution for preparing a solid polymer electrolyte by using ethylene carbonate, lithium salt and a porous support material, wherein the polymer electrolyte realizes remarkable improvement of ion conductivity at room temperature, but has low mechanical property and electrochemical window. In carrying out the present invention, the inventors have found that there are at least problems in the prior art in that in solid-state batteries, three parameters of ionic conductivity, electrochemical window and mechanical properties are mutually constrained, and improvement of one property tends to face a decrease in the other property. Accordingly, it remains quite challenging to provide a novel functional filler that can simultaneously enhance the mechanical properties of the polymer electrolyte and the uniform and efficient lithium ion transport, while improving the interfacial compatibility between the filler and the polymer matrix. Disclosure of Invention The invention aims to solve the technical problems of low ionic conductivity, poor mechanical property and unstable electrolyte/electrode interface of the traditional polyvinylidene fluoride-based solid polymer electrolyte membrane, and provides a tough solid polymer electrolyte membrane with high mechanical property, high ionic conductivity and wide electrochemical stability window. In order to solve the technical problems, the invention adopts the following technical scheme: In one aspect, a tough solid polymer electrolyte membrane is provided comprising a polyvinylidene fluoride matrix and poly (2-cyano-paraphenylene terephthalamide) and lithium salts dispersed in the polyvinylidene fluoride matrix; the mass ratio of the poly (2-cyano-paraphenylene terephthalamide) to the polyvinylidene fluoride matrix is 5% -15%. On the other hand, the preparation method of the tough solid polymer electrolyte membrane comprises the following steps: dispersing 2, 5-diaminobenzonitrile and a neutralizing agent in an organic solvent under the condition of inert low temperature to obtain a2, 5-diaminobenzonitrile solution; adding a polybasic acyl chloride monomer into the 2, 5-diaminobenzonitrile solution in batches, standing at room temperature, and regulating to be neutral by using a neutralizing agent; treating the polymer with deionized water and methanol to adjust to a neutral system, precipitating the polymer, carrying out suction filtration, collecting a solid phase, washing and drying to obtain poly (2-cyano-p-phenylene terephthalamide); And mixing the poly (2-cyano-p-phenylene terephthalamide), polyvinylidene fluoride and lithium salt in a solvent to obtain a blending system, and volatilizing the solvent to form a film to obtain the tough solid polymer electrolyte membrane. In still another aspect, there is provided an application of the tough solid polymer electrolyte membrane described above or the tough solid polymer electrol