A kind of phosphate-coated lithium cobalt oxide cathode material and preparation method thereof

Abstract

The invention belongs to the field of battery materials, and specifically discloses a polymetallic phosphate-coated lithium cobaltate positive electrode material and a preparation method thereof. The invention creatively coats a polymetallic phosphate layer on the surface of a lithium cobaltate positive electrode material matrix to prepare The method is as follows: Add the prepared metal salt solution and polymer compound in pure water to react, then add lithium cobaltate aqueous solution after dispersion, stir and heat at the same time to form a gel; mix the gel evenly and add it to a mechanical fusion compactor The coating of the material is completed in the process; finally, the lithium cobalt oxide cathode material coated with polymetallic phosphate is obtained after rapid and efficient sintering at a lower temperature and then natural cooling with the furnace. The cladding layer on the surface of the lithium cobaltate positive electrode material of the present invention is a fast ion conductor, which can improve the rate performance of the material; it can also prevent the reaction between the electrode and the electrolyte, and slow down the capacity fading of the lithium cobaltate material; at the same time, the present invention The advanced technology can effectively reduce the amount of residual lithium in the finished product and improve its storage performance.

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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