Modified Ni-Co-Mn ternary material and preparation method thereof

Abstract

The invention discloses a modified Ni-Co-Mn ternary material. The material is a core-shell structure, and an inner core is aluminum-doped Ni-Co-Mn ternary material, and the shell is a carbon claddinglayer; the mole ratio of the Ni: Co: Mn in the inner core is 8: 1: 1 to 5: 2: 3, the mole ratio of the Al / (Ni+Co+Mn) is 1%-5%, the shell is the carbon-cladding layer with uniform thickness, and the weight of the carbon cladding layer is 0.5%-2% of the total weight of the modified Ni-Co-Mn ternary material. By optimizing the doping amount of the Al and the carbon cladding layer thickness, the material capacity is further improved. The invention further discloses a preparation method of the material at the same time. The material can be used as positive active materials of the lithium primary battery, a lithium secondary battery, a lithium ion secondary battery and like lithium batteries; and the modified Ni-Co-Mn ternary material has excellent electrochemical performances of being high in specific capacity, high in conductivity and good in stability.

Description

technical field [0001] The invention relates to the field of cathode materials for lithium ion secondary batteries, in particular to a modified nickel-cobalt-manganese ternary material and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, high specific energy, long cycle life, light weight, less self-discharge, no memory effect and high cost performance, and have become a research hotspot for researchers. Cathode material is one of the core parts of lithium-ion batteries, which determines the performance of lithium-ion batteries. At present, the biggest bottleneck that limits the energy density, power density, cycle life and safety of lithium-ion power batteries lies in the cathode material technology. [0003] At present, the nickel-cobalt-lithium-manganese oxide ternary material (NCM) in the cathode material of lithium-ion batteries has received extensive attention from researchers. The NCM mater...

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Problems solved by technology

[0004] Although the NCM ternary cathode material has many of the above advantages, due to the cation mixing effect and the change of the surface microstructure of the material during the first charging process, the first charge and discharge efficiency of the ternary material is not high; and the lithium ion diffusion coefficient and electronic conductivity The low rate makes the rate performance of the material unsatisfactory; the ternary material will have a strong side reaction with the organic electrolyte in a wide voltage range, which will increase the impedance of the battery during charge and discharge, and reduce the electrochemical performance of the material.

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