Positive electrode material and preparation method and application thereof

Abstract

The invention relates to a positive electrode material which comprises an inner core, a first shell layer and a second shell layer, the inner core is coated with the first shell layer, the first shell layer is coated with the second shell layer, the weight of the inner core material accounts for 70-85% of the total weight of the positive electrode material, and the weight of the first shell layer material accounts for 10-25% of the total weight of the positive electrode material. And the weight of the second shell layer material is 2-5% of the total weight of the positive electrode material. The material of the inner core is LiFe1-x-aMnxMaPO4, M is at least one of Ti, Zr and Al, x is more than or equal to 0.7 and less than or equal to 0.9, and a is more than or equal to 0.01 and less than or equal to 0.05. The first shell layer is made of LiFe1-y-bMnyNbPO4, N is at least one of Ti, Zr and Al elements, y is more than or equal to 0 and less than or equal to 0.2, and b is more than or equal to 0.01 and less than or equal to 0.05. And the material of the second shell layer is Li3V2 (PO4) 3. The invention also relates to a preparation method of the positive electrode material and application of the positive electrode material.

Description

technical field [0001] The invention relates to the technical field of battery preparation, in particular to a positive electrode material of a lithium ion battery and a preparation method and application thereof. Background technique [0002] Lithium-ion batteries are widely used in small portable devices, new energy vehicles, energy storage and other fields. At present, the positive electrode materials used in lithium-ion batteries include: layered materials such as lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium cobalt oxide, etc.; spinel structure materials such as lithium manganate and lithium nickel manganese oxide; and olive Stone structure materials such as lithium iron phosphate, lithium manganese phosphate, lithium manganese iron phosphate, etc. Among them, phosphate-based positive electrode materials are widely used in the field of new energy vehicles due to their excellent safety performance and cycle performance, but the technical prob...

AI Technical Summary

Problems solved by technology

However, since the positive electrode material is in direct contact with the electrolyte, there is still the problem of Mn dissolution, and the conductivity of the positive electrode material is poor, so it is necessary to further improve the performance of the positive electrode material