Double layer clad lithium ion battery cathode material and preparation method thereof

Abstract

The invention discloses a double layer clad lithium ion battery cathode material and a preparation method thereof. The cathode material takes a lithium nickel cobalt manganese oxide ternary material as a matrix, and the surface of the matrix is clad with silicon lithium salt cladding and metal oxide cladding. The silicon lithium salt cladding is formed through the following steps: mixing silicon weak acid with the matrix, and carrying out a neutralization reaction on the silicon weak acid and residual alkali on the surface of the matrix to generate a layer of silicon lithium salt with which the matrix is clad. The metal oxide is mixed with the matrix which is clad with the silicon lithium salt, and the matrix is clad with a layer of the metal oxide cladding through physical cladding. The double layer clad lithium ion battery cathode material reduces the amount of the residual alkali on the surface of the lithium nickel cobalt manganese oxide matrix material, and prevents a side reaction of an electrolyte and the matrix material. Furthermore, the cathode material has high rate performance, high specific capacity and good cycle performance. In addition, the method is simple and is easy in operation and large scale production.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular relates to a nickel-rich ternary positive electrode material, in particular to a double-layer coated lithium ion battery positive electrode material and a preparation method thereof. Background technique [0002] Lithium-ion battery ternary cathode materials have the advantages of high working voltage, high energy density, long cycle life, low self-discharge rate, and no memory effect. They are widely used in electronic equipment and electric vehicle power batteries and other fields. [0003] For the nickel-rich ternary cathode material, as the nickel content increases, its cycle performance becomes worse, because the material easily absorbs moisture and carbon dioxide in the air, and then generates impurities such as lithium hydroxide and lithium carbonate, which are deposited on the surface of the cathode. , which increases the interfacial internal resistance; in addition, sin...

AI Technical Summary

Problems solved by technology

[0003] For the nickel-rich ternary cathode material, as the nickel content increases, its cycle performance becomes worse, because the material easily absorbs moisture and carbon dioxide in the air, and then generates impurities such as lithium hydroxide and lithium carbonate, which are deposited on the surface of the cathode. , which increases the interfacial internal resistance; in addition, since the positive electrode is in the delithiated state, the Ni 4+ It is very unstable and highly reactive, so it is easier to cause the reaction between the electrode and the electrolyte to generate high interfacial internal resistance under high nickel content. The combined effect leads to rapid decay of material capacity and poor cycle performance. At the same time, the residual alkali ( Lithium hydroxide, lithium carbonate) will react with the aluminum foil of the battery current collector to release part of hydrogen gas under high temperature conditions, and the gas will expand

Images