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Positive electrode material and preparation method thereof, lithium battery positive electrode sheet and solid lithium battery

A technology of positive electrode material and positive electrode active material, which is applied in the field of positive electrode material and its preparation, positive electrode sheet of lithium battery and solid-state lithium battery, can solve the problems of hindering transmission, poor compatibility, low ionic conductivity, etc., to achieve coating The effect of firmness and tightness, good compatibility and high conductivity

Active Publication Date: 2022-03-15
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to overcome the low ion conductivity of oxide materials existing in the prior art, which seriously hinders Li + The transmission at the interface, the problem of limited improvement in reducing the interface impedance, and the poor compatibility between the oxide and the sulfide electrolyte material will cause problems such as a space charge layer, and provide a positive electrode material and its preparation Method and lithium battery positive electrode sheet and solid lithium battery, the lithium battery positive electrode sheet uses fluorinated TiS 2 The material is used as a coating to coat the positive electrode sheet of the lithium battery. Firstly, TiS 2 The ionic conductivity is higher, and the fluorinated TiS 2 The structure is stable, and it can be better compatible with solid electrolyte materials that are also sulfides. It can improve the positive electrode interface, effectively reduce the interface impedance, and increase the Li + The transmission rate can improve the electrochemical performance of solid-state lithium batteries in all aspects.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0029] A second aspect of the present invention provides a preparation method of a positive electrode material, wherein the preparation method comprises the following steps:

[0030] (1) The positive active material, tetrabutyl titanate, ammonium sulfide and ethanol are subjected to the first reaction to obtain TiS 2 coated positive active material;

[0031] (2) The TiS 2 Coated cathode active material with TiF 4 Carry out the second reaction to obtain fluorinated TiS 2 Coated cathode material.

[0032] According to the present invention, the first reaction and the second reaction can be carried out in a closed container, wherein the closed container is not particularly limited, for example, it can be a glove box, and the glove box can be obtained commercially, for example, for example , can be purchased from Braun Inert Gas Systems (Shanghai) Co., Ltd., the model is Unilab1250.

[0033] According to the present invention, in step (1), the conditions of the first reaction...

Embodiment 1

[0078] This example is used to illustrate the positive electrode material and the preparation method thereof, as well as the positive electrode sheet and the all-solid-state battery of the present invention.

[0079] (1) Preparation of positive electrode sheet C

[0080] First prepare fluorinated TiS 2 Material-coated positive active material, the positive active material body is LiCoO 2 Materials, the specific preparation method is, 1000g LiCoO 2 (particle size is 5μm), 150gLi 10 GeP 2 S 12 Solid electrolyte material (ionic conductivity 1×10 -2 S / cm, electronic conductivity 2×10 -12 S / cm, particle size 5μm), 61mL tetrabutyl titanate, 12.1g ammonium sulfide (NH 4 ) 2 Put S and 500 mL of ethanol into a closed reaction vessel with a volume of 5 L, turn on stirring, and heat to 250 ° C after sealing. After 2 h of reaction, the obtained black powder precipitate is taken out, and heated to 800 ° C in air for 4 h to obtain TiS 2 Coated LiCoO 2 material, then mix this mater...

Embodiment 2

[0090] This example is used to illustrate the positive electrode material and the preparation method thereof, as well as the positive electrode sheet and the all-solid-state battery of the present invention.

[0091] The solid electrolyte was prepared according to the same method as in Example 1, except that: in the preparation of the positive electrode sheet C in step (1), fluorinated TiS was prepared 2 Material-coated LiCoO 2 materials, instead of using 61 mL of tetrabutyl titanate and 12.1 g of ammonium sulfide (NH 4 ) 2 S, but 122 mL of tetrabutyl titanate, 24.2 g of ammonium sulfide (NH 4 ) 2 S (ie, 4% TiS 2 +0.5%TiF 4 ), the coating thickness of the product is 150 nm.

[0092] As a result, the battery of this embodiment is obtained, which is marked as S2.

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Abstract

The invention relates to the field of lithium batteries, and discloses a positive electrode material and a preparation method thereof, a lithium battery positive plate and a solid lithium battery. The positive electrode material includes a positive electrode active material and fluorinated TiS coated on the positive electrode active material 2 Material. The present invention uses fluorinated TiS 2 Material-coated positive electrode active material, fluorinated TiS 2 The high ionic conductivity of the material is favorable for Li + Transport at interfaces; fluorinated TiS 2 The presence of F in the material structure ‑ , the structure is more stable, which is conducive to the improvement of battery cycle stability; and fluorinated TiS 2 The material coating process is simple, which can alleviate the interdiffusion of elements with the positive electrode material during the preparation process, and is more conducive to the electrochemical performance of the positive electrode material.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a positive electrode material and a preparation method thereof, as well as a positive electrode sheet of a lithium battery and a solid-state lithium battery. Background technique [0002] Existing all-solid-state lithium batteries based on inorganic solid electrolytes use traditional positive electrode materials or coat the surface of the positive electrode material, wherein the coating material is oxides, transition metal oxides containing lithium, and the like. such as LiNbO 3 , LiTaO 3 , Li 4 Ti 5 O 12 , Al 2 O 3 etc., in which LiNbO 3 Coated cathode materials are the most widely used. [0003] CN106935796A discloses a sulfur / sulfide / copper ternary composite positive electrode and its preparation and application in magnesium-sulfur batteries. The sulfur / sulfide / copper ternary composite positive electrode contains sublimated sulfur, metal sulfide and metal copper foil....

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/13H01M4/36H01M4/58H01M10/0525
CPCH01M4/36H01M4/5815H01M4/13H01M10/0525Y02E60/10
Inventor 历彪郭姿珠易观贵
Owner BYD CO LTD