Phosphate-coated lithium cobalt oxide positive electrode material and preparation method thereof

Abstract

The invention belongs to the field of battery materials, and particularly discloses a multi-metal phosphate coated lithium cobalt oxide positive electrode material and a preparation method thereof. According to the invention, the surface of the lithium cobalt oxide positive electrode material substrate is creatively coated with the multi-metal phosphate layer. The preparation method comprises the following steps: adding a prepared metal salt solution and a high-molecular compound into pure water for reaction, adding a lithium cobalt oxide aqueous solution after dispersion, and heating while stirring to form gel; uniformly mixing the gel, and adding the gel into a mechanical fusion compaction machine to complete material coating; and finally, quickly and efficiently sintering at a relatively low temperature, and naturally cooling along with the furnace to obtain the multi-metal phosphate coated lithium cobalt oxide positive electrode material. The coating layer on the surface of the matrix of the lithium cobalt oxide positive electrode material is a fast ion conductor, so that the rate capability of the material can be improved; the reaction between the electrode and the electrolyte can be prevented, and the capacity fading of the lithium cobalt oxide material is slowed down; and meanwhile, the residual lithium amount of the finished product can be effectively reduced, and the storage performance of the finished product is improved.

Description

technical field [0001] The invention belongs to the field of battery materials, and more specifically relates to a phosphate-coated lithium cobalt oxide cathode material and a preparation method thereof. Background technique [0002] The commercial application of lithium-ion batteries has achieved rapid development, and has been widely used in 3C digital batteries and electric vehicles. The positive electrode material is the core part of lithium-ion batteries, and its types include lithium cobalt oxide, lithium iron phosphate and ternary materials. Among them, lithium cobalt oxide has high specific capacity, energy density and power density. However, the electrochemical performance, thermal stability, and structural stability of lithium cobalt oxide still need to be further improved, especially in high temperature and high voltage test environments. With the increase of charging voltage, these problems become more prominent, which seriously limit the development and applic...

AI Technical Summary

Problems solved by technology

This type of patent uses wet mixing combined with the material filtration, washing and sintering process brought about by the post-heat treatment process. The process is complex and the processing time is lengthy, which will result in reduced production efficiency and increased costs.

The existing technology also has the problem that the fast ion conductor coating is unevenly distributed and cannot completely cover the surface of the positive electrode material, which also affects the improvement effect of the fast ion conductor coating on the electrochemical performance, and the performance improvement effect still needs to be improved

In addition, the coating layer and the base material of the existing wet coating process are not tightly bonded, and they are easy to fall off, and the material will still undergo structural phase transformation in the subsequent electrochemical process, resulting in a decrease in capacity.

In addition, the existing lithium salt coating process easily leads to high residual lithium on the surface of the positive electrode material, which is prone to side reactions with the electrolyte and affects its storage performance.

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