Positive electrode material, modification method thereof and battery

Abstract

The invention provides a modification method of a positive electrode material. The modification method comprises the following steps: preparing lithium-rich phase powder containing lithium, nickel, cobalt, manganese and oxygen; mixing a coating material with a dispersing agent and a solvent, ultrasonically dispersing, dropwise adding into the lithium-rich phase powder, grinding to be dry, and calcining to obtain a coating product, wherein the coating material is selected from one or more of potassium hexafluorophosphate and potassium metaphosphate. The modification method comprises the following steps: performing surface modification treatment on xLi2MnO3. (1-x) LiNiyCozMn1-y-zO2 lithium-rich phase powder through potassium hexafluorophosphate and / or potassium metaphosphate, and performingin-situ decomposition on the potassium hexafluorophosphate at high temperature to form a potassium metaphosphate coating layer with a three-dimensional structure. The first coulombic efficiency, the cycling stability and the rate capability of the lithium-rich phase material subjected to surface coating treatment are all improved, so that relatively good electrochemical comprehensive performance is obtained, and the development requirements of high-power electronic equipment can be met. The preparation method of the positive electrode material is simple, wide in application range, low in costand suitable for industrial production.

Description

technical field [0001] The invention relates to the technical field of energy storage materials, in particular to a positive electrode material, a modification method thereof and a battery. Background technique [0002] As the country gives more and more policy support to new energy vehicles, the new energy vehicle market will continue to heat up, which will drive the development of the power lithium-ion battery material industry. The existing plan clearly requires that by 2020, the specific energy of the new lithium-ion power battery will exceed 300 Wh / kg; the specific energy of the system will strive to reach 260 Wh / kg, the cost will be reduced to less than 1 yuan / Wh, and the use environment will reach -30°C to 55°C, can have 3C charging capability. By 2025, breakthroughs will be made in the power battery technology of the new system, and the specific energy of a single unit will reach 500 Wh / kg. At present, commercial cathode materials mainly include LiMn 2 o 4 Spinel...

AI Technical Summary

Problems solved by technology

However, there are also some problems in the lithium-rich phase, such as low initial Coulombic efficiency, poor cycle stability, poor rate performance, voltage decay during cycling, and unstable high and low performance, etc.

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