High-nickel ternary positive electrode material with single crystal morphology and preparation method of high-nickel ternary positive electrode material

Abstract

The invention discloses a high-nickel ternary positive electrode material with single crystal morphology and a preparation method of the high-nickel ternary positive electrode material. The positive electrode material is formed by a base material and a coating layer, wherein the base material is prepared from a high-nickel ternary precursor, a lithium source and a doping agent; the doping agent comprises a doping element, the doping element is a metal element, the coating layer is formed by a coating material, the coating material comprises a coating element, and the coating element is a metalelement and/or a non-metal element. The positive electrode material is obtained by mixing the high-nickel ternary precursor, the lithium source and the doping agent, performing primary sintering, then mixing with the coating material, and performing secondary sintering. The high-nickel ternary positive electrode material disclosed by the invention has the advantages of single crystal morphology,smooth surface, small specific surface area and high compaction density, and the single crystallization of the high-nickel ternary positive electrode material improves the specific capacity and cycleperformance of the positive electrode material and prolongs the service life of the positive electrode material. The preparation method is simple in process, easy to implement and beneficial to industrial large-scale production.

Description

technical field [0001] The invention belongs to the field of positive electrode materials for lithium ion batteries, and in particular relates to a high-nickel ternary positive electrode material with a single crystal morphology and a preparation method thereof. Background technique [0002] In recent years, with the national policy's key support for the new energy field, the development of the new energy automobile industry has become increasingly prosperous. With the high capacity demand of pure electric vehicles for power batteries, nickel-cobalt-manganese ternary cathode materials are gradually replacing the early lithium iron phosphate series and lithium manganate due to their higher material specific capacity and relatively good high-temperature and low-temperature performance. The positive electrode material has become the mainstream product in the market. [0003] Due to the higher nickel content of high-nickel ternary cathode materials, the discharge specific capac...

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Problems solved by technology

[0003] Due to the higher nickel content of high-nickel ternary cathode materials, the discharge specific capacity can generally reach more than 200mAh / g, but because nickel ions are easily reduced and enter the lithium layer, this material often produces serious ion mixing. phenomenon; and the reduction of nickel ions will also lead to the generation of active oxygen free radicals, which are very easy to react with the electrolyte on the surface of the material, and the corresponding side reactions will cause flatulence in the battery, etc., and lead to a serious decline in battery cycle performance; another On the one hand, traditional ternary materials are secondary spherical particles formed by the self-assembly of primary particles. The particle size of primary particles is small and there are many internal defects. At the same time, the structural strength of secondary particles is relatively low. Fragmentation will occur during the process, and these unfavorable factors will lead to deterioration of the performance of the material during charge and discharge

[0004] Since the high-nickel ternary cathode material itself already has a relatively high cycle capacity, the single crystallization of the material can further improve the defect of its poor cycle performance, but due to the particularity of the processing process, its cost is relatively high

The patent application with application number CN201710883429.3 focuses on the use of liquid additives and high-pressure spray pretreatment to obtain high-capacity high-nickel cathode materials; the patent application with application number CN201611037434.4 focuses on the use of large particle grinding to obtain small particle precursors body and sintered to obtain small-particle positive electrode materials, the above-mentioned materials have good electrochemical properties, but both doping and sintering processes are relatively complicated, which will increase the processing cost in the actual production process

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