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CN-122025763-A - All-solid electrolyte membrane, preparation method and application

CN122025763ACN 122025763 ACN122025763 ACN 122025763ACN-122025763-A

Abstract

The application provides an all-solid electrolyte membrane, a preparation method and application, wherein the all-solid electrolyte membrane comprises a first solid electrolyte layer, a second solid electrolyte layer and a third solid electrolyte layer, the second solid electrolyte layer is positioned between the first solid electrolyte layer and the third solid electrolyte layer, the first solid electrolyte layer comprises a first binder and a first solid electrolyte, the crystallinity of the first binder is 50-70%, the second solid electrolyte layer comprises a second binder and a second solid electrolyte, the crystallinity of the second binder is 96-99%, the third solid electrolyte layer comprises a third binder and a third solid electrolyte, and the crystallinity of the third binder is 50-70%. The all-solid electrolyte membrane provided by the application not only ensures good lithium ion interface transmission, but also has good mechanical strength and puncture resistance, and the electrochemical performance and safety of the lithium ion battery are obviously improved.

Inventors

  • YU LE
  • ZHENG DAWEI

Assignees

  • 远景动力技术(湖北)有限公司
  • 远景动力技术(江苏)有限公司
  • 远景睿泰动力技术(上海)有限公司

Dates

Publication Date
20260512
Application Date
20260303

Claims (10)

  1. 1. An all-solid electrolyte membrane characterized in that the all-solid electrolyte membrane comprises a first solid electrolyte layer, a second solid electrolyte layer and a third solid electrolyte layer, wherein the second solid electrolyte layer is positioned between the first solid electrolyte layer and the third solid electrolyte layer; Wherein the first solid electrolyte layer includes a first binder and a first solid electrolyte, the first binder having a crystallinity of 50% to 70%; The second solid state electrolyte layer includes a second binder and a second solid state electrolyte, the second binder having a crystallinity of 96% to 99%; the third solid electrolyte layer includes a third binder and a third solid electrolyte, the third binder having a crystallinity of 50% to 70%; The first binder, the second binder and the third binder are respectively and independently selected from any one or more of polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, ethylene-vinyl acetate copolymer, polypropylene, polyethylene, ethylene-octene copolymer and polyimide.
  2. 2. The all-solid electrolyte membrane according to claim 1, wherein: the content of the first binder in the first solid electrolyte layer is 1wt% to 2wt%; In the second solid electrolyte layer, the content of the second binder is 0.5wt% to 1wt%; In the third solid electrolyte layer, the content of the third binder is 1wt% to 2wt%.
  3. 3. The all-solid electrolyte membrane according to claim 1, wherein: The thickness ratio of the first solid electrolyte layer, the second solid electrolyte layer, and the third solid electrolyte layer is (0.8 to 1.2): 3 to 5): 0.8 to 1.2.
  4. 4. The all-solid electrolyte membrane according to claim 1, wherein: The first solid electrolyte, the second solid electrolyte, and the third solid electrolyte are each independently selected from at least one of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte.
  5. 5. A preparation method of an all-solid-state electrolyte membrane binder is characterized by comprising the following steps, Heating the binder raw material to 10-30 ℃ above the melting point of the binder raw material in an inert atmosphere, adjusting and controlling the heating rate to 5-10 ℃ per minute, and carrying out heat preservation treatment for a specific time to obtain the treated binder raw material; Preparing and obtaining a first adhesive based on the treated adhesive raw material, wherein the preparation method comprises the steps of adjusting and controlling the cooling rate to be 50-100 ℃ per minute, and cooling the temperature to room temperature to obtain the first adhesive, wherein the crystallinity of the first adhesive is 50-70%; The raw material of the adhesive is selected from any one or more of polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, ethylene-vinyl acetate copolymer, polypropylene, polyethylene, ethylene-octene copolymer and polyimide.
  6. 6. The method of manufacturing according to claim 5, wherein: The first binder has a standard specific gravity of 2.14g/cm3 to 2.16g/cm3, a bulk density of 350g/L to 400g/L, and a corresponding extrusion pressure of 20MPa to 40MPa at a temperature of 380 ℃ plus or minus 50 ℃.
  7. 7. A preparation method of an all-solid-state electrolyte membrane binder is characterized by comprising the following steps, Heating the binder raw material to 10-30 ℃ above the melting point of the binder raw material in an inert atmosphere, adjusting and controlling the heating rate to 5-10 ℃ per minute, and carrying out heat preservation treatment for a specific time to obtain the treated binder raw material; Preparing and obtaining a second binder based on the treated binder raw material, wherein the preparation method comprises the steps of adjusting and controlling the cooling rate to be 0.1-0.3 ℃ per minute, cooling the temperature to 350 ℃, adjusting and controlling the cooling rate to be 0.5-1 ℃ per minute, cooling the temperature to 300 ℃, and quenching to obtain the second binder, wherein the crystallinity of the second binder is 96-99%; The raw material of the adhesive is selected from any one or more of polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, ethylene-vinyl acetate copolymer, polypropylene, polyethylene, ethylene-octene copolymer and polyimide.
  8. 8. The method of manufacturing according to claim 7, wherein: The second binder has a standard specific gravity of 2.18g/cm3 to 2.20g/cm3, a bulk density of 450g/L to 550g/L, and a corresponding extrusion pressure of 80MPa to 120MPa at a temperature of 380 ℃ plus or minus 50 ℃.
  9. 9. A preparation method of an all-solid electrolyte membrane is characterized by comprising the following steps, Mixing a first solid electrolyte with a first binder to obtain a first mixed material, wherein the crystallinity of the first binder is 50-70%; mixing a second solid electrolyte with a second binder to obtain a second mixed material, wherein the crystallinity of the second binder is 96-99%; mixing a first solid electrolyte with a first binder to obtain a first mixed material, wherein the crystallinity of the first binder is 96-99%; Carrying out fibrosis treatment on the first mixed material and the second mixed material to obtain a first fibrillated material and a second fibrillated material respectively; crushing and granulating the first fibrillated material and the second fibrillated material to obtain a first electrolyte material and a second electrolyte material respectively; after the first electrolyte material is formed into a film, a first solid electrolyte layer and a third solid electrolyte layer are obtained through thinning operation; After the second electrolyte material is formed into a film, a second solid electrolyte layer is obtained through thinning operation; Placing the second solid electrolyte layer stack over the first solid electrolyte layer and placing the third solid electrolyte layer stack over the second solid electrolyte layer to form an all-solid electrolyte layer structure; and thinning the all-solid electrolyte layer structure to obtain the all-solid electrolyte membrane.
  10. 10. A lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte membrane, wherein the electrolyte membrane comprises the all-solid electrolyte membrane according to any one of claims 1 to 4 or the all-solid electrolyte membrane produced by the production method according to claim 9.

Description

All-solid electrolyte membrane, preparation method and application Technical Field The application belongs to the technical field of power batteries, and particularly relates to an all-solid electrolyte membrane, a preparation method and application thereof. Background The core of the all-solid-state battery as a next generation power battery system is that inflammable and easily-leaked organic liquid electrolyte in the traditional lithium ion battery is replaced by nonflammable inorganic solid-state electrolyte, so that the thermal safety of the battery is greatly improved from the source of materials. In all-solid-state batteries, the all-solid electrolyte membrane plays a crucial dual role of not only conducting lithium ions with high efficiency and constructing an ion transmission channel, but also isolating electrons effectively and preventing internal short circuits. However, during charge and discharge cycles, the electrode active material repeatedly expands and contracts in volume with the release and intercalation of lithium ions. This continuous deformation causes debonding of the interface between the all-solid electrolyte membrane and the electrode, which ultimately results in rapid decay of the cell capacity and deterioration of the cycle life. To improve the interface, the industry adopts a dry process to prepare a multilayer electrolyte membrane. However, the existing technology still has the defects that firstly, effective differentiation of mechanical properties between electrolyte layers is difficult to realize under the condition of not changing the types or the content of the binder, and the complexity of the technology is increased, secondly, the used binder easily causes the electrolyte layer to have over-high rigidity and insufficient flexibility, can not be tightly contacted with an electrode in the circulation process, and has insufficient interface stability, so that the electrochemical performance of the battery is deteriorated. Therefore, how to provide an all-solid electrolyte membrane with both optimized interface contact and rigidity is a development difficulty in the current energy storage lithium ion battery technology. Disclosure of Invention The application aims to provide an all-solid electrolyte membrane, a preparation method and application thereof, wherein the all-solid electrolyte membrane can be tightly contacted with an electrode in a circulating process, has good lithium ion interface transmission capacity, and also has good mechanical strength and puncture resistance, so that the electrochemical performance and safety of a lithium ion battery are effectively improved. In order to solve the technical problems, the application provides an all-solid electrolyte membrane, which comprises a first solid electrolyte layer, a second solid electrolyte layer and a third solid electrolyte layer, wherein the second solid electrolyte layer is positioned between the first solid electrolyte layer and the third solid electrolyte layer; Wherein the first solid electrolyte layer includes a first binder and a first solid electrolyte, the first binder having a crystallinity of 50% to 70%; The second solid state electrolyte layer includes a second binder and a second solid state electrolyte, the second binder having a crystallinity of 96% to 99%; the third solid electrolyte layer includes a third binder and a third solid electrolyte, the third binder having a crystallinity of 50% to 70%; The first binder, the second binder and the third binder are respectively and independently selected from any one or more of polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, ethylene-vinyl acetate copolymer, polypropylene, polyethylene, ethylene-octene copolymer and polyimide. In an embodiment of the present application, in the first solid electrolyte layer, the first binder is contained in an amount of 1wt% to 2wt%; In the second solid electrolyte layer, the content of the second binder is 0.5wt% to 1wt%; In the third solid electrolyte layer, the content of the third binder is 1wt% to 2wt%. In one embodiment of the present application, the thickness ratio of the first solid state electrolyte layer, the second solid state electrolyte layer, and the third solid state electrolyte layer is (0.8 to 1.2): 3 to 5): 0.8 to 1.2. In an embodiment of the present application, the first solid electrolyte, the second solid electrolyte, and the third solid electrolyte are each independently selected from at least one of an oxide solid electrolyte, a sulfide solid electrolyte, and a halide solid electrolyte. The application provides a preparation method of an adhesive for an all-solid electrolyte membrane, which comprises the following steps: Heating the binder raw material to 10-30 ℃ above the melting point of the binder raw material in an inert atmosphere, adjusting and controlling the heating rate to 5-10 ℃ per minute, and carrying out heat preservation treatment for a specific time to obtain the