Long-circulation and high-power lithium ion battery positive electrode material and preparation method thereof

Abstract

The invention discloses a long-circulation and high-power lithium ion battery positive electrode material, of which the molecular formula is LiNi<x>Co<y>Mn<1-x-y-z>Z O<2>. The long-circulation and high-power lithium ion battery positive electrode material comprises a single crystal or quasi-single crystal shell layer and a hollow part, wherein the single crystal or quasi-single crystal shell layer is formed by mutual fusion of primary particles, and the volume of the hollow part of secondary particles accounts for 0.8-50% of the volume of the whole secondary particles. The invention further discloses a preparation method, which comprises the following steps of: preparing a hydroxide precursor with crystallinity and morphology difference in the radial direction; and mixing the precursor with a lithium compound, and carrying out two-stage sintering on the mixture to obtain the lithium ion battery positive electrode material, wherein the first sintering is rapid heating, the temperature of the second sintering is higher than that of the first stage, and the second sintering enables the primary particles to be fused and mutually fused to form a single single crystal shell layer. The lithium ion battery positive electrode material disclosed by the invention is good in normal-temperature and high-temperature cycle performance and safety performance, can improve mechanical and electrochemical performance and compaction density, has the characteristics of quick charge, high capacity, high voltage, high cycle and low cost, and can be suitable for high-power motor vehicles.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and in particular relates to a long-cycle, high-power lithium-ion battery cathode material and a preparation method thereof. Background technique [0002] As a new type of green energy storage device, lithium-ion battery occupies a pivotal position in the field of secondary batteries due to its superior performance. Among them, the positive electrode material is the core that affects the performance of lithium-ion batteries. At present, the positive electrode materials used in lithium-ion batteries mainly include lithium cobaltate, lithium manganese oxide, lithium iron phosphate and ternary materials. [0003] However, with the continuous improvement of energy density and the incentives of national policies, power batteries have shown rapid development, and ternary materials have been used by many new energy vehicles due to their high capacity advantages. The ternary materials that ar...

AI Technical Summary

Problems solved by technology

[0004] The present invention aims at some problems existing in current power positive electrode materials, and aims to provide a long-cycle, high-power lithium-ion battery single-crystal hollow positive electrode material and its preparation method to improve the compaction and cycle performance of the material

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