Lithium nickel cobalt manganate composite positive pole material and its preparation method and lithium battery

Abstract

The invention relates to a lithium nickel cobalt manganate composite positive pole material and its preparation method and lithium battery and belongs to the technical field of lithium battery materials. The lithium nickel cobalt manganate composite positive pole material comprises lithium nickel cobalt manganate particles and lithium iron phosphate layers on the surfaces of the lithium nickel cobalt manganate particles. The lithium nickel cobalt manganate particles are lithium nickel cobalt manganate secondary particles. The lithium nickel cobalt manganate secondary particles are coated withlithium iron phosphate so that the surface pH of the lithium nickel cobalt manganate material is reduced, the residual lithium on the surface of the material is reduced, the problem that the existinglithium nickel cobalt manganate material adsorbs more water in slurry mixing is solved, the processing properties of the material are improved, the stability of the material during charging and discharging of the battery is improved and the circulation of the battery is improved.

Description

technical field [0001] The invention relates to a nickel-cobalt lithium manganate composite positive electrode material, a preparation method thereof, and a lithium battery, belonging to the technical field of lithium battery materials. Background technique [0002] With the increasing popularity of electric vehicles, the demand for longer mileage poses a higher challenge to the energy density of power batteries. According to the goal proposed in the "Energy Saving and New Energy Automobile Industry Development Plan (2012-2020)", by 2020, the energy density of the power battery module should reach 300Wh / kg (the corresponding single battery energy density should reach at least 330Wh / kg above). To improve the energy density of batteries, the key lies in the breakthrough of battery material technology. [0003] At present, in order to increase the energy density of batteries, most domestic power battery manufacturers generally use high-nickel ternary materials or high-voltage...

AI Technical Summary

Problems solved by technology

However, these methods all have certain defects: on the one hand, the bulk phase doping of inactive material elements will lead to the loss of battery capacity; on the other hand, in order to improve the rate performance and process performance of the battery, most ternary cathode materials use Spherical or spherical secondary particles, so whether it is doped on the surface of the precursor or the surface of the finished product, it can only be doped on the surface of the secondary particles, and the primary particles located inside the secondary particles are not protected. Since the surface of the secondary particles can be in contact with the electrolyte during charging and discharging, the NCM811 material after doping and coating cannot meet the cycle and safety requirements of the battery.

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