A kind of preparation method of high voltage lithium cobalt oxide cathode material

Abstract

The invention discloses a preparation method of a high-voltage lithium cobalt oxide positive electrode material: (1) three cobalt tetroxide containing a doping element M, a lithium source, an oxide containing a doping element M', a grain refiner and a flux mixing to obtain a primary mixture; (2) sintering and crushing the primary mixture to obtain a primary sintered powder; (3) mixing the primary sintered powder and the coating to obtain a secondary mixture; (4) The secondary mixture is sintered and pulverized to obtain a lithium cobalt oxide cathode material. The doping of the present invention is divided into two methods of pre-blending and dry mixing to solve the problem of segregation of doping elements in the product on a microscopic scale; the coulter type mixing technology is used to solve the problem of segregation of different substances during mixing; the grain refiner Combining with flux to synthesize materials with mixed morphology; adopting technologies such as doping element surface crystallization catalysis and cladding; the performance of high-voltage lithium cobalt oxide is significantly improved.

Description

technical field [0001] The invention belongs to the anode material of a lithium ion battery, in particular to a preparation method of a high-voltage lithium cobaltate anode material. Background technique [0002] With the rapid development of electronic technology, the replacement of 3C products is becoming more and more frequent, and the development of lithium-ion battery cathode materials with higher energy density and better cycle performance has become the goal pursued by the lithium battery industry. Lithium cobalt oxide (LiCoO 2 ) has the advantages of high specific capacity, high compaction density, high volumetric energy density, and simple production process. It is widely used in consumer electronics products such as smartphones, tablet computers, and notebooks, and has become the most commonly used lithium-ion battery cathode for commercialization. one of the materials. The theoretical capacity of lithium cobalt oxide is 274mAh / g. During normal use, only half of ...

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Problems solved by technology

High-voltage lithium cobalt oxide with single crystal morphology is generally obtained by sintering at high temperature (>1050°C) and long time (>12h) in one sintering process. The specific surface area of ​​the single crystal material obtained by this method is smaller than that of The side reaction of the electrolyte is reduced, and the cycle performance is improved; however, due to the large single particle size, the material has poor rate and low first Coulombic efficiency, which reduces the energy utilization rate of the material

The high-voltage lithium cobalt oxide with a similar single crystal morphology is generally obtained by sintering at a lower temperature (<1000°C) and for a shorter time (<8h) at one time. The single crystal-like material obtained by this method is obtained by The secondary ball composed of large primary particles has a better magnification and higher primary Coulombic efficiency due to the small size of the primary particles; but its specific surface area is large and the side reaction with the electrolyte increases, and because it Secondary spherical particles are easy to crack when the stage is rolled, causing degradation of cycle performance

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