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CN-121983653-A - All-solid electrolyte membrane and preparation method and application thereof

CN121983653ACN 121983653 ACN121983653 ACN 121983653ACN-121983653-A

Abstract

The invention belongs to the technical field of all-solid electrolyte materials, and discloses an all-solid electrolyte membrane with a three-layer structure, wherein a sulfide intermediate electrolyte layer is prepared by slurry wet coating, and an ultrathin elastic electrolyte layer is formed by spraying or spin coating on two sides of the sulfide intermediate electrolyte layer, so that the preparation of the all-solid electrolyte membrane is realized; the all-solid electrolyte membrane has the composite structural characteristics of high ion conductivity of sulfide solid electrolyte and high flexibility of ultrathin elastic electrolyte layer, has excellent interface adaptability and room-temperature ion conductivity, can obviously reduce interface impedance and inhibit space charge layer effect, and has higher cycle stability and multiplying power performance, thus having important industrial application value of power batteries and energy storage.

Inventors

  • LIU LIWEN
  • WANG CHENG
  • LIU JINYUN
  • ZHU LINGYUN
  • HUANG XIUYING

Assignees

  • 芜湖天弋能源科技有限公司

Dates

Publication Date
20260505
Application Date
20260130

Claims (10)

  1. 1. The all-solid electrolyte membrane is characterized by being divided into an upper layer, an intermediate layer and a lower layer, wherein the intermediate layer is a sulfide solid electrolyte membrane, and the upper layer and the lower layer are ultrathin elastic electrolyte layers.
  2. 2. The all-solid electrolyte membrane according to claim 1, wherein the sulfide solid electrolyte membrane has a thickness of 10 to 50 μm and the ultrathin elastic electrolyte layer has a thickness of 1 to 10 μm.
  3. 3. A method for producing the all-solid electrolyte membrane according to claim 1 or 2, comprising the steps of: S1, uniformly mixing sulfide solid electrolyte, a binder and a solvent, coating to obtain an electrolyte membrane intermediate, and drying and hot-pressing the electrolyte membrane intermediate to obtain a sulfide solid electrolyte membrane; S2, coating a lithium-conducting crystal material on the surface of a sulfide solid electrolyte to obtain a core-shell structure electrolyte material, mixing the core-shell structure electrolyte material, a binder, a high-elasticity nanofiber material and a solvent, and performing vacuum defoaming to obtain ultrathin elastic electrolyte layer slurry; s3, respectively spraying the ultrathin elastic electrolyte layer slurry on two sides of the sulfide solid electrolyte membrane, and drying to obtain a three-layer solid electrolyte membrane; And S4, carrying out vacuum drying and hot pressing on the three-layer solid electrolyte membrane to obtain the all-solid electrolyte membrane.
  4. 4. The method according to claim 3, wherein in the step S1, the sulfide solid electrolyte is one or more of a sulfide silver germanium ore type sulfide solid electrolyte, a lithium sulfide super-ion conductor type sulfide solid electrolyte, a glassy sulfide solid electrolyte or a crystalline sulfide solid electrolyte, the sulfide silver germanium ore type sulfide solid electrolyte has a chemical formula of Li 7-(a+b) PS 6-(a+b) X a Y b , wherein X and Y are one or two of Cl or Br, and 0≤a+b≤1.7, the lithium sulfide super-ion conductor type sulfide solid electrolyte has a chemical formula of one of Li 10 SnP 2 S 12 or Li 10 GeP 2 S 12 , the glassy sulfide solid electrolyte has a chemical formula of one of Li 3 PS 4 or Li 3.2 PS 4 I 0.2 , and the crystalline sulfide solid electrolyte has a chemical formula of Li 7 P 3 S 11 .
  5. 5. The method for producing an all-solid electrolyte membrane according to claim 3 or 4, wherein in step S1, the mass ratio of the sulfide solid electrolyte, the binder and the solvent is 1:0.001 to 0.1:0.3 to 5.
  6. 6. The method according to claim 4, wherein in the step S2, the lithium-conducting crystal material is one or more of Li 7 La 3 Zr 2 O 12 、Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 、Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 、Li 3 InCl 6 、Li 3 YCl 6 、Li 2 ZrCl 6 、Li 6 PS 5 Cl、Li 6 PS 5 Br、Li 2 ZrF 6 、LiNbO 3 、Li 3 BO 3 and Li 3 PO 4 , and the D50 particle size of the lithium-conducting crystal material is 0.1-0.5 μm.
  7. 7. The method for preparing an all-solid electrolyte membrane according to any one of claims 3, 4 and 6, wherein in step S2, the mass ratio of the lithium-conducting crystal material to the sulfide solid electrolyte in the core-shell structure electrolyte material is 1:9-100.
  8. 8. The method for preparing an all-solid electrolyte membrane according to claim 3, wherein in the step S2, the material of the high-elasticity nanofiber material is one or more of thermoplastic polyurethane, thermoplastic polyamide, polycaprolactone or polylactic acid, the fiber diameter of the high-elasticity nanofiber material is 30-1000 nm, and the fiber length is 100-30000 nm.
  9. 9. The method for preparing an all-solid electrolyte membrane according to claim 3, wherein in step S2, the mass ratio of the amounts of the core-shell structure electrolyte material, the binder, the high-elasticity nanofiber material and the solvent in the ultra-thin elastic electrolyte layer slurry is 90-99.9:0.1-10:0.1-1:50-1000.
  10. 10. Use of the all-solid electrolyte membrane according to claim 1 or 2 in a solid state battery.

Description

All-solid electrolyte membrane and preparation method and application thereof Technical Field The invention relates to the field of all-solid electrolyte membranes, in particular to an all-solid electrolyte membrane and a preparation method and application thereof. Background With the rapid development of new energy automobiles, the requirements on the energy density and the safety performance of the automobile energy storage device are continuously improved, and the lithium ion battery with the advantages of high specific energy, high specific power, good circularity, no environmental pollution and the like is considered as the best choice. By 2030, power cell energy densities above 500Wh/kg are expected. Because the all-solid-state battery has the problems of poor solid/solid interface contact, lithium dendrite, a space charge layer, large interface impedance and the like, in order to improve the interface contact problem, particularly, larger assembly pressure is needed, the interface contact is improved, and the practical application of the all-solid-state battery is severely limited by high pressure. An all-solid electrolyte membrane is one of key components of an all-solid battery, and the intrinsic properties such as mechanical strength, stability or ion conductivity of the electrolyte membrane are important to the influence of the all-solid battery. It is necessary to prepare a thinner electrolyte membrane of high ion conductivity while ensuring a certain strength and toughness of the electrolyte membrane. In addition, the interface problem of the electrolyte membrane and the positive and negative electrode sheets is one of the key factors limiting the application of all-solid-state batteries. The repeated shrinkage and expansion of the active material accompanied during the charge-discharge cycle is liable to cause mechanical failure at the interface, and the impedance is remarkably increased. Particularly, in the low-pressure and high-rate charge-discharge process, the space point charge effect is obvious, the ion transmission is blocked, and the performance of the solid-state battery is reduced. Disclosure of Invention The invention aims to provide an all-solid electrolyte membrane and a preparation method thereof, wherein a slurry wet coating is adopted to prepare an intermediate electrolyte layer, and two sides of the intermediate electrolyte layer are respectively coated with an ultrathin elastic electrolyte layer by adopting a spray coating or spin coating method to obtain the all-solid electrolyte membrane. The invention provides an all-solid electrolyte membrane which is divided into an upper layer, an intermediate layer and a lower layer, wherein the intermediate layer is a sulfide solid electrolyte membrane, and the upper layer and the lower layer are ultrathin elastic electrolyte layers. In the all-solid electrolyte membrane, the thickness of the sulfide solid electrolyte membrane is 10-50 microns, and the thickness of the ultrathin elastic electrolyte layer is 1-10 microns. The invention provides a preparation method of an all-solid electrolyte membrane, which comprises the following steps: S1, uniformly mixing sulfide solid electrolyte, a binder and a solvent, coating to obtain an electrolyte membrane intermediate, and drying and hot-pressing the electrolyte membrane intermediate to obtain a sulfide solid electrolyte membrane; S2, coating a lithium-conducting crystal material on the surface of a sulfide solid electrolyte to obtain a core-shell structure electrolyte material, mixing the core-shell structure electrolyte material, a binder, a high-elasticity nanofiber material and a solvent, and performing vacuum defoaming to obtain ultrathin elastic electrolyte layer slurry; s3, respectively spraying the ultrathin elastic electrolyte layer slurry on two sides of the sulfide solid electrolyte membrane, and drying to obtain a three-layer solid electrolyte membrane; And S4, carrying out vacuum drying and hot pressing on the three-layer solid electrolyte membrane to obtain the all-solid electrolyte membrane. In step S1 of the above preparation method, the thickness of the electrolyte membrane intermediate is 20 to 200 μm, and preferably, the thickness of the electrolyte membrane intermediate is 30 to 150 μm. In step S1 of the above preparation method, the mixing method is one of double-planetary vacuum stirring mixing, single-shaft paddle mixing or ball milling mixing. In the step S1 of the preparation method, the mass ratio of the sulfide solid electrolyte to the binder to the solvent is 1:0.001-0.1:0.3-5. In the steps S1 and S2 of the preparation method, the D50 particle size of the sulfide solid electrolyte is 1-10 mu m, preferably the D50 particle size of the sulfide solid electrolyte is 5 mu m, the sulfide solid electrolyte is one or more of a silver sulfide germanium sulfide type sulfide solid electrolyte, a lithium sulfide super-ion conductor type sulfide solid electrolyte, a glass st