A kind of preparation method of potassium metavanadate dispersion coating nickel-cobalt-manganese ternary positive electrode material

Abstract

The invention discloses a method for preparing a nickel-cobalt-manganese ternary positive electrode material dispersed and coated with potassium metavanadate. Firstly, the sulfate solution of Ni, Co and Mn is mixed and then co-precipitated under alkaline conditions to prepare the ternary positive electrode material. Composite precursor (Ni x co y mn z ) (OH) 2 , and then washed with deionized water, beating, and filtered to obtain a slurry, adding lithium source and potassium metavanadate to the slurry, followed by homogeneous refinement treatment, spray drying and high-temperature calcination to obtain a potassium metavanadate dispersion package Nickel-cobalt-manganese ternary cathode material. The present invention coats KVO on the surface of the ternary positive electrode 3 , improve the stability of the surface structure of the material, and at the same time increase the ion mobility of the material, thereby improving the electrochemical performance of the ternary material; the nickel-cobalt-manganese ternary positive electrode material prepared by the present invention has good dispersion, uniform size, and high sphericity , The secondary particles are loose, which is conducive to the infiltration of the electrolyte, and improves the diffusion rate of lithium ions, thereby improving the rate performance and cycle performance.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a method for preparing a nickel-cobalt-manganese ternary cathode material dispersed and coated with potassium metavanadate. Background technique [0002] As we all know, the lithium-ion power batteries for vehicles in the early stage of my country mainly use lithium iron phosphate batteries. The theoretical gram capacity of lithium iron phosphate materials is 170mAh / g, and the working voltage is 3.20V. The energy density of lithium iron phosphate single batteries can reach up to 140Wh / Kg. In order to further meet the long-mileage demand of pure electric vehicles, how to increase the energy density of batteries has become a difficult problem faced by the government and major companies. According to my country's "Energy Saving and New Energy Automobile Industry Development Plan 2012~2020" about high specific energy lithium-ion battery product index planning, by 2020, ...

AI Technical Summary

Problems solved by technology

However, there are still many problems as lithium nickel cobalt manganese oxide as the positive electrode material of lithium ion battery. First, at high potential, Mn 3+ Disproportionation reaction occurs and dissolves from the surface of the active material. Secondly, structural distortion is prone to occur in the process of repeated lithium deintercalation, resulting in rapid capacity decay, especially at higher temperatures, the phenomenon of capacity decay is more prominent

[0004] Conventional modification methods such as doping and coating, although the discharge specific capacity is improved to a certain extent, are all added mechanically, which has the problem of aggregation, and it is difficult to mix the materials uniformly, resulting in unstable performance improvement, and due to solid phase diffusion The speed is slow and the mixing is difficult to be uniform, resulting in low stability of electrochemical performance and poor cycle performance

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