Cobalt-free positive electrode material of high-voltage lithium ion battery and preparation method thereof

Abstract

The invention discloses a cobalt-free positive electrode material of a high-voltage lithium ion battery. A single-crystal nickel-manganese binary material or a single-crystal nickel-aluminum binary material is used as a matrix, the outer surface of the matrix is coated with a fast ion conductor layer, and the material of the fast ion conductor layer is selected from one or more of Li10GeP2S12, Li2CsI3, LiNbO3, Li3NbO4, LiTaO3 and Li7TaO6. The preparation method comprises the following steps of mixing the binary material matrix, the fast ion conductor source material and absolute ethyl alcohol, carrying out wet grinding, sintering the obtained mixture, and crushing to obtain the cobalt-free positive electrode material of the high-voltage lithium ion battery. The components of the material do not contain Co, the material cost is greatly reduced, meanwhile, the surface of the positive electrode material matrix is coated with the fast ion conductor layer, the content of residual lithium on the surface of the material is reduced, and the specific discharge capacity performance and the cycle performance of the lithium ion battery positive electrode material are improved.

Description

technical field [0001] The invention belongs to the field of positive electrode materials for lithium ion batteries, in particular to a cobalt-free positive electrode material for high-voltage lithium ion batteries and a preparation method thereof. Background technique [0002] With the rapid development of new energy and electric vehicle industries, people's requirements for a series of performances such as cruising range, cost, and safety of vehicle batteries are gradually increasing. Moreover, safety problems of high-nickel batteries have occurred frequently in recent years, and the limited reserves of Co contained in them will lead to high battery costs. [0003] In order to solve the above problems, many researchers focus on reducing cobalt. For example, in the patent application with the application number CN202010118544.3, the NMC811 single crystal ternary material prepared from the nickel-cobalt salt precursor, the manganese source and the lithium source is used, an...

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Problems solved by technology

The defect of the material inside the single crystal particles prepared by the invention is significantly reduced, which can effectively improve the stability of the structure of the positive electrode material during the charging and discharging process, thereby improving the service life of the lithium-ion battery, but it is within the working voltage range of 2.8V to 4.35V 0.1C rate discharge, the first discharge capacity is only 189mAh / g, which cannot meet the needs of the current lithium-ion battery power market, and the electrochemical performance of the cobalt-free cathode material will deteriorate sharply under high voltage, which seriously hinders the development of lithium-ion battery cathode materials. Industrialization process towards high voltage

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