Positive electrode material with low internal resistance for solid state lithium battery and preparation method of positive electrode material

Abstract

The invention provides a positive electrode material with low internal resistance and particularly relates to a positive electrode material with low internal resistance for a solid state lithium battery and a preparation method of the positive electrode material. The positive electrode material with low internal resistance is prepared from a positive electrode active material core and a surface composite material layer covering the positive electrode active material core, wherein the surface composite material layer is mainly prepared from a nano long-range conducting material and a single ionconductor polymer material. The positive electrode material with low internal resistance, provided by the invention, has higher electronic conductivity and lithium ion conductivity and can effectively reduce the internal resistance of the solid state lithium battery; because the positive electrode active material core and the surface composite material layer have strong interaction, the phenomenaof granule cracking and grinding caused by volume deformation of the positive electrode active material core in repeated charging and discharging process can be effectively inhibited so as to ensurethe structural integrity of the positive electrode active material core and good interface stability; and furthermore, the technical scheme provided by the invention is simple and easy, low in production cost and suitable for performing large-scale production.

Description

technical field [0001] The invention relates to the technical field of preparation of lithium ion batteries, in particular to a positive electrode material of a solid lithium battery and a preparation method of the positive electrode material. Background technique [0002] Lithium-ion batteries have become a research hotspot in the fields of portable electronics, power tools and electric vehicles due to their high energy density. However, the continuous intelligence of portable electronic products will greatly increase the power consumption of lithium-ion batteries. Therefore, the low energy density of batteries becomes the main factor affecting the length of standby time. On the other hand, the demand for cruising range and safety of electric vehicles also puts forward new requirements for existing commodity lithium-ion batteries. Therefore, in recent years, countries around the world have actively deployed and developed solid-state lithium battery technology that takes in...

AI Technical Summary

Problems solved by technology

However, due to the different thermal expansion coefficients between the active material and the lithium conductive oxide and carbon material, there is a possibility that the carbon-containing and lithium conductive oxide coating layer cannot grow closely on the surface of the active material particle during the heat treatment process. It will reduce the contact area between the active material and the coating layer material and increase the interfacial resistance

Especially for positive electrode active material particles with irregular particle shape, it is difficult to achieve uniform coating of lithium conductive oxides and carbon materials on the corners and edges of positive electrode active material particles by the above coating method

Moreover, the carbon-containing and lithium conductive oxides formed on the surface of the active material particles after heat treatment do not possess flexibility, and are difficult to adapt to the volume deformation of the positive active material during repeated charging and discharging, and are easy to peel off and fall off from the surface of the positive active material particles, Destroy the lithium ion and electron transport channels of the positive electrode active material, increase the internal resistance of the battery, and reduce the performance of the battery

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