Modified positive electrode material and preparation method thereof

Abstract

The invention discloses a modified positive electrode material and a preparation method thereof, and relates to the technical field of batteries. The positive electrode material comprises an inner core, a first coating layer and a second coating layer which are sequentially arranged from inside to outside, wherein the inner core is a lithium nickel cobalt aluminate positive electrode material, thefirst coating layer is copper oxide, and the second coating layer is a carbon sphere. The modified positive electrode material is prepared by a secondary coating modification means; the surface of the lithium nickel cobalt aluminate is coated with uniform and compact coating layer copper oxide and high-conductivity nano carbon spheres, thereby avoiding the direct contact between the electrolyte and the active material, improving the transmission rate of electrons and the diffusion rate of lithium ions while the structure is stabilized in the charging and discharging process, and finally improving the cycle performance and the rate capability of an NCA positive electrode material. According to the method, the surface of the ternary positive electrode material NCA is coated with copper oxide through a spray drying method, and the NCA is subjected to carbon coating by an ultrasonic wetting assisting chemical method, so that the problems of poor cycle performance, poor rate capability andthe like of the NCA material can be solved.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a modified positive electrode material and a preparation method thereof. Background technique [0002] In recent years, with the rapid development of portable devices and long-range electric vehicles, higher requirements have been placed on the comprehensive performance (energy density, cycle life, rate performance, and safety performance) of rechargeable lithium-ion batteries. Traditional cathode materials such as LiCoO 2 、LiFePO 4 Due to its low energy density, it has gradually been used as a high-nickel cathode material LiNi x m 1- x o 2 (X>0.6, M=Co, Mn, Al) instead. In high-nickel positive electrode materials, nickel-cobalt lithium aluminate (LiNi 0.8 co 0.15 Al 0.05 o 2 , referred to as NCA) due to its excellent discharge specific capacity (> 180mA h g -1 ), high energy density and relatively low cost have been successfully used as power batteries in Tesl...

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Problems solved by technology

[0006] Another object of the present invention includes providing a method for preparing a modified positive electrode material, which uses a spray drying method to carry out surface copper oxidation on the ternary positive electrode material NCA Coating, followed by carbon spheres prepared by hydrothermal method, and ultrasonic wet-assisted chemical method to carbon-coat NCA, which solves the problems of poor cycle performance and poor rate performance of NCA materials.

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