A kind of composite ternary positive electrode material and preparation method thereof

Abstract

The invention relates to a composite ternary positive electrode material and a preparation method thereof. The material has a core-shell structure, the inner core is a nickel-cobalt-manganese ternary positive electrode material, and the molecular formula is LiNi x Co y Mn z O 2 , where 0≤x<1, 0≤y<1, 0≤z<1, and x+y+z=1; the shell is niobate, and the molecular formula is MNbO 3 , wherein M is at least one of Ln, Zn, Zr, Ce or Ti. The invention uses niobate to coat the ternary positive electrode material, which can enhance the ion and electron transport of the ternary positive electrode material, effectively improve the cycle and rate performance of the material, effectively reduce the residual alkali content of the material, and improve the thermal stability of the material. , to improve the safety performance of the material. In the preparation process, the sol-gel method is used to first obtain the nano-niobate, and then heat treatment for coating, the process is simple and easy to realize, and has a good application prospect.

Description

technical field [0001] The invention relates to the field of lithium ion battery preparation, in particular to a composite ternary positive electrode material and a preparation method thereof. Background technique [0002] With the rapid development of electric vehicles, lithium batteries are more widely used, and lithium battery materials develop rapidly. The longer range of electric vehicles requires lithium-ion batteries with higher energy density. Ternary materials combine the advantages of cathode materials such as lithium cobaltate, lithium nickelate and lithium manganate, and have the characteristics of high energy density, long cycle life, good safety, and relatively low cost. According to data, at present, the proportion of ternary cathode materials for power batteries in China is about 30%. [0003] Ternary materials, especially high-nickel materials, are easy to interact with CO in the external environment during storage. 2 and H 2 The O reaction then generate...

AI Technical Summary

Problems solved by technology

[0003] Ternary materials, especially high-nickel materials, are easy to interact with CO in the external environment during storage. 2 and H 2 O reaction and then generate lithium-containing compounds on the surface of the material. In addition, transition metal ions with high oxidation activity in the charged state catalyze the decomposition of the electrolyte, which accelerates the consumption of the electrolyte and generates a thick solid electrolyte interface layer on the surface of the material, which not only reduces the Battery safety performance, while affecting the material's large rate and cycle performance

[0005] Although the above method improves the electrochemical performance of the ternary cathode material by coating, it still has certain limitations. is limited and needs to be further improved

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