CN-121983540-A - Sulfide all-solid-state battery positive electrode material and preparation method thereof

CN121983540ACN 121983540 ACN121983540 ACN 121983540ACN-121983540-A

Abstract

The invention belongs to the technical field of battery anode materials, and discloses a sulfide all-solid-state battery anode material and a preparation method thereof. The positive electrode material comprises a positive electrode active material and a sulfide solid electrolyte, wherein the sulfide solid electrolyte comprises a sulfide matrix and a coating layer coated on the surface of the sulfide matrix, and the positive electrode active material and part of the coating layer are compounded through the rapid ion conductor layer generated in situ by mixing and sintering the positive electrode active material and the sulfide solid electrolyte. According to the invention, the air stability of the surface of the sulfide solid electrolyte is improved through twice sintering (presintering and sintering), and the interface contact resistance of the sulfide matrix and the positive electrode active material is reduced through the in-situ generated fast ion conductor layer.

Inventors

LI WENHUI
Ping Guozheng
YANG HUIMIN
YUAN WENJING
AN HONGLI
SONG RANRAN
Li Mianqian
WANG FANG
LIU GUIJUAN
LI JITAO

Assignees

北京新能源汽车股份有限公司
北京新能源汽车股份有限公司蓝谷动力系统分公司

Dates

Publication Date: 20260505
Application Date: 20260121

Claims (10)

1. A sulfide all-solid state battery positive electrode material, characterized in that the positive electrode material comprises: a positive electrode active material and a sulfide solid state electrolyte; the sulfide solid electrolyte comprises a sulfide matrix and a coating layer coated on the surface of the sulfide matrix; And the positive electrode active material and part of the coating layer are compounded through the rapid ion conductor layer generated in situ by mixing the positive electrode active material and sulfide solid electrolyte and then sintering.
2. The sulfide all-solid battery positive electrode material according to claim 1, wherein the positive electrode active material is LiNi x Co y Mn z M 1-x-y-z O 2 , wherein M is at least one of Al, zr, ti, nb, W and Ta, 0.8≤x <1,0.03≤y <0.2,0.9≤x+y+z≤1.
3. The sulfide all-solid battery positive electrode material according to claim 1, wherein the mixing mass ratio of the positive electrode active material and the sulfide solid electrolyte is (60-95): 5-40.
4. The sulfide all-solid battery positive electrode material according to claim 1, wherein the sulfide matrix is at least one of Li 7 P 3 S 11 、Li 3 PS 4 、Li 6 PS 5 Cl、Li 6 PS 5 Br and Li 10 GeP 2 S 11 .
5. The sulfide all-solid battery positive electrode material according to claim 1, wherein the material of the coating layer is at least one of Al 2 O 3 、CoO、NiO 2 、TiO 2 、AlF 3 、TiF 4 and NbF 5 .
6. The positive electrode material for sulfide all-solid state battery according to claim 1, wherein the sintering operation conditions include an inert gas atmosphere, a temperature rise rate of 1-8 ℃ per minute, a sintering temperature of 300-800 ℃, a sintering heat preservation time of 4-10h, cooling with a furnace, and a tapping temperature of 200 ℃ or less.
7. The sulfide all-solid state battery positive electrode material according to claim 1, wherein, The positive electrode material further comprises a binder and a conductive agent; the all-solid-state battery is an all-solid-state lithium ion battery or an all-solid-state sodium ion battery.
8. A method for producing a positive electrode material for a sulfide all-solid state battery as claimed in any one of claims 1 to 7, characterized by comprising the steps of: s1, mixing materials of the sulfide matrix and the coating layer, and presintering to obtain the sulfide solid electrolyte; and S2, mixing the positive electrode active material with the sulfide solid electrolyte, and then sintering and sieving to obtain the sulfide all-solid-state battery positive electrode material.
9. The method for producing a sulfide all-solid state battery positive electrode material according to claim 8, wherein, in the step S1: the mixing mass ratio of the materials of the sulfide matrix and the coating layer is 100 (0.05-0.5); The mixing mode is ball milling, the rotational speed of the ball milling is 300-2000r/min, and the time is 2-6h; The presintering operation conditions comprise kiln equipment, inert gas atmosphere, heating rate of 1-8 ℃ per minute, sintering temperature of 50-400 ℃ and sintering heat preservation time of 1-8h.
10. The method for producing a sulfide all-solid state battery positive electrode material according to claim 8, wherein, in the step S2: The mixing mass ratio of the positive electrode active material to the sulfide solid electrolyte is (60-95): 5-40; The mixing mode is ball milling, the rotational speed of the ball milling is 800-1000r/min, and the time is 4-8h; The sintering operation conditions comprise kiln, inert gas atmosphere, heating rate of 1-8 ℃ per min, sintering temperature of 300-800 ℃, sintering heat preservation time of 4-10h, furnace cooling, and furnace discharging temperature of less than or equal to 200 ℃; The sieving is performed by a 300-400 mesh screen.

Description

Sulfide all-solid-state battery positive electrode material and preparation method thereof Technical Field The invention belongs to the technical field of battery anode materials, and particularly relates to an all-solid-state sulfide battery anode material and a preparation method thereof. Background Lithium ion power batteries have received extensive attention from the market for large-scale applications, but the development of commercialization thereof has been restricted by the difficult problems of some key technologies of battery materials. The positive electrode material is a core key material of the power lithium battery, the energy density of the positive electrode material is closely related to the endurance mileage of the electric automobile, and the urgent problem of energy shortage is faced, so that the positive electrode material with high energy density, long service life, high safety and low cost is rapidly developed and is important for the future. From the standpoint of electrolyte, all-solid batteries can be classified into three types of sulfides, polymers and oxides, where sulfides are considered as the final route for all-solid batteries. However, the existing sulfide solid electrolyte has the main defects of poor air stability, easiness in chemical reaction with water or oxygen to generate harmful gases such as H 2 S and the like to influence the ionic conductivity of the material, easiness in side reaction with an anode active material, low oxidation potential of sulfide, unstable surface of a high-nickel anode active material due to mixed arrangement of lithium and nickel and the like, and unavoidable interface side reaction at an interface between the sulfide and the high-nickel anode active material, thus preventing the application of the sulfide solid electrolyte in an all-solid lithium battery. At present, in order to solve the direct contact between sulfide and high-nickel positive electrode active material, a method is generally adopted in which an inert substance is coated on the surface of the positive electrode active material or sulfide material, so that side reaction is reduced. However, in the charge and discharge process, the inert coating layer can construct an isolation layer, prevent the ion transmission speed in the positive electrode active material or the sulfide material, reduce the electrochemical reactivity of the positive electrode active material, especially the non-contact part of the sulfide and the positive electrode active material, greatly reduce the activity of the positive electrode active material, increase the reaction internal resistance, increase the polarization and influence the capacity exertion of the positive electrode active material due to the existence of the coating layer. Therefore, a new positive electrode material of sulfide all-solid-state battery and a preparation method thereof are needed to be proposed. Disclosure of Invention The invention aims at overcoming the defects of the prior art and provides a sulfide all-solid-state battery anode material and a preparation method thereof. According to the invention, the air stability of the surface of the sulfide solid electrolyte is improved through twice sintering (presintering and sintering), and the interface contact resistance of the sulfide matrix and the positive electrode active material is reduced through the in-situ generated fast ion conductor layer. In order to achieve the above object, an aspect of the present invention provides a sulfide all-solid state battery positive electrode material comprising: a positive electrode active material and a sulfide solid state electrolyte; the sulfide solid electrolyte comprises a sulfide matrix and a coating layer coated on the surface of the sulfide matrix; And the positive electrode active material and part of the coating layer are compounded through the rapid ion conductor layer generated in situ by mixing the positive electrode active material and sulfide solid electrolyte and then sintering. The method comprises the steps of mixing sulfide matrix and material of a coating layer, pre-sintering, coating a layer of compound coating layer on the surface of the sulfide matrix, stabilizing the structure of the sulfide matrix, improving the air stability of the sulfide matrix, obtaining sulfide solid electrolyte after pre-sintering, mixing sulfide solid electrolyte after pre-sintering with positive electrode active material, sintering, and generating a fast ion conductor layer in situ at the contact part of the coating layer of the sulfide solid electrolyte after pre-sintering and the positive electrode active material (the fast ion conductor layer is formed by sintering the positive electrode active material and the material of the coating layer), wherein the non-contact part of the coating layer of the sulfide solid electrolyte after pre-sintering and the positive electrode active material can stabilize the compound coating layer on the su