CN-121983656-A - Lithium ion halide solid electrolyte material, preparation method and application thereof

Abstract

The invention discloses a lithium ion halide solid electrolyte material, a preparation method and application thereof, wherein the chemical general formula of the halide solid electrolyte is Li x MCl 4‑y F x+y , x is more than or equal to 0 and less than or equal to 2, y is more than or equal to x, and M is one or two of transition metal elements Hf and Zr. A method for preparing lithium ion halide solid electrolyte material. The halide solid electrolyte is used for preparing a solid electrolyte or a composite positive electrode of a lithium ion all-solid battery. According to the invention, F is introduced to promote the amorphization of the electrolyte, which is the reason for remarkably improving the conductivity of the electrolyte, and F has high electronegativity to enhance the high-voltage stability of the electrolyte, so that the provided lithium ion halide solid electrolyte has high ion conductivity, good high-voltage stability and mechanical stability in a solid battery system.

Inventors

• LV YINGCHUN
• XU SIQI
• ZHOU JINGJING
• LU SHIGANG

Assignees

• 上海大学

Dates

Publication Date

20260505

Application Date

20260304

Claims (8)

1. 1. A lithium ion halide solid electrolyte material is characterized in that the chemical general formula of the halide solid electrolyte is Li x MCl 4-y F x+y , wherein x is more than or equal to 0 and less than or equal to 2, x is more than or equal to y and less than or equal to x, and M is one or two of transition metal elements Hf and Zr.
2. 2. The lithium-ion halide solid electrolyte material of claim 1, wherein the halide solid electrolyte has an amorphous or low crystallinity structure.
3. 3. The lithium-ion halide solid electrolyte material of claim 2, wherein the halide solid electrolyte has a room temperature ionic conductivity of greater than 0.05 mS/cm.
4. 4. The method for preparing the lithium ion halide solid electrolyte material according to claim 3, wherein the reaction equation is xLiF +MCl 4 =Li x MCl 4 F x , the precursors LiF and MCl 4 are weighed according to the stoichiometric ratio of the structural general formula of the electrolyte, and the precursors and ball-milling beads are mixed and ball-milled at room temperature under an inert atmosphere to obtain the lithium ion halide solid electrolyte powder.
5. 5. The method for preparing a lithium ion halide solid electrolyte material according to claim 3, wherein the method is characterized in that precursors LiF and MCl 4 、LiCl、MF 4 are weighed according to the stoichiometric ratio of the structural general formula of the electrolyte, and the precursors and ball-milling beads are mixed and ball-milled at room temperature under inert atmosphere to obtain lithium ion halide solid electrolyte powder, and the reaction equation is as follows: xLiF+MCl 4 +4/yMF 4 =Li x MCl 4-y F x+y or (x+y) LiF+MCl 4 +(-y)LiCl=Li x MCl 4-y F x+y Or (x-4+y) LiF+ (4-y) LiCl+MF 4 =Li x MCl 4-y F x+y Or xLiCl + (1-x/4-y/4) MCl 4 +(x/4+y/4)MF 4 =Li x MCl 4-y F x+y .
6. 6. The method for preparing the lithium-ion halide solid electrolyte material according to claim 4 or 5, wherein the ball milling speed is 400-600 rpm, the ball milling time is 5-15 h, and the mass ratio of the precursor mixture to the ball milling beads is 1 (20-60).
7. 7. The method for preparing a lithium-ion halide solid electrolyte material according to claim 6, wherein the ball milling speed is 500 rpm, the ball milling time is 10-15 h, and the mass ratio of the precursor mixture to the ball milling beads is 1:52.
8. 8. The method according to claim 1, wherein the halide solid electrolyte is used for preparing a solid electrolyte or a composite positive electrode of a lithium ion all-solid battery.

Description

Lithium ion halide solid electrolyte material, preparation method and application thereof Technical Field The invention relates to a lithium ion halide solid electrolyte material, in particular to a lithium ion halide solid electrolyte material, a preparation method and application thereof, and belongs to the technical field of solid electrolytes. Background The rapid development of electric vehicles and energy storage systems has put higher demands on secondary batteries in terms of safety, energy density and service reliability. Conventional lithium ion batteries generally adopt organic liquid electrolytes, and the electrolytes are easy to leak, burn and even explode under the conditions of overcharge, high temperature or mechanical damage, so that the electrolytes become one of important factors for limiting the lithium batteries to further improve the safety performance and the energy density. Therefore, the construction of lithium solid-state batteries using solid-state electrolytes instead of liquid electrolytes is considered as an important technical route for improving the intrinsic safety of batteries and achieving high energy density. The existing solid electrolyte mainly comprises a sulfide system, an oxide system, a halide system and the like. The sulfide solid electrolyte has high lithium ion conductivity, but is sensitive to water and air, has the problem of insufficient stability in the preparation, storage and application processes, and has high chemical stability, but has the defects of high sintering temperature, low lithium ion conductivity at room temperature, poor interface contact with electrode materials and the like. In contrast, a halide solid electrolyte has been attracting attention in recent years because of its high lithium ion conductivity, relatively good air stability, and suitability for high-voltage positive electrode materials. The formation of fluorine-containing solid electrolytes by the introduction of fluorine elements in halogen solid electrolyte systems is considered to be an effective way to improve the overall properties of the materials. Related researches show that the introduction of fluorine element can adjust the composition and structural characteristics of the solid electrolyte to a certain extent and has influence on the electrochemical stability, mechanical property and interface compatibility of the solid electrolyte, thereby providing possibility for improving the overall performance of the lithium solid battery. However, the existing fluorine-containing solid electrolyte still faces a plurality of problems in practical application, for example, while part of the fluorine-containing solid electrolyte improves the structural stability, the lithium ion migration performance may be adversely affected, so that the ion conductivity is difficult to further improve. In addition, a large interface impedance may still exist between the fluorine-containing solid electrolyte and the high-voltage positive electrode active material, which affects the cycle stability and the rate performance of the battery. Therefore, how to realize effective regulation and control of the composition of the fluorine-containing solid electrolyte on the premise of ensuring the structural stability and electrochemical stability of the material, and to give consideration to higher lithium ion conductivity and good electrode interface compatibility, is still a technical problem to be solved in the technical field of lithium solid batteries. Disclosure of Invention In order to solve the defects of the technology, the invention provides a lithium ion halide solid electrolyte material, and a preparation method and application thereof. In order to solve the technical problems, the technical scheme adopted by the invention is that the lithium ion halide solid electrolyte material has a chemical general formula of Li xMCl4-yFx+y, wherein x is more than or equal to 0 and less than or equal to 2, y is more than or equal to y and less than or equal to x, and M is one or two of transition metal elements Hf and Zr. Preferably, the structure of the halide solid electrolyte is an amorphous or low crystallinity structure. The low crystallinity structure means that the crystallinity of the crystal material is lower, and the crystal material has a crystal structure similar to Li 2ZrCl6, belongs to a trigonal system and has a space group of p3-m1. Preferably, the halide solid state electrolyte has a room temperature ionic conductivity greater than 0.05 mS/cm. Preferably, the precursor LiF and MCl 4 are weighed according to the stoichiometric ratio of the structural general formula of the electrolyte, and the precursor and ball-milling beads are mixed and ball-milled at room temperature under inert atmosphere to obtain lithium ion halide solid electrolyte powder, wherein the reaction equation is xLiF +MCl 4=LixMCl4Fx. Preferably, the precursor LiF and MCl 4、LiCl、MF4 are weighed according to the stoichiometr