Nickel-cobalt lithium manganate positive electrode material applied to high-voltage lithium ion batteries and preparation method thereof

Abstract

The invention discloses a nickel-cobalt lithium manganate positive electrode material applied to high-voltage lithium ion batteries. The chemical formula of nickel-cobalt lithium manganate is Li(NixCoyMn1-x-y)1-a-bLaaAlbO2, wherein a is greater than or equal to 0 and is less than or equal to 0.05, b is greater than or equal to 0 and is less than or equal to 0.1, x is greater than or equal to 0.3 and is less than or equal to 0.8, and y is greater than or equal to 0.05 and is less than or equal to 0.4. A preparation method of the nickel-cobalt lithium manganate positive electrode material comprises the following steps: carrying out ball milling and mixing a nickel-cobalt-manganese precursor, a lanthanum source, an aluminum source and lithium salt in a horizontal ball mill, then pre-sinteringthe obtained mixture in a muffle furnace, then carrying out secondary ball milling and mixing the obtained mixture in the horizontal ball mill, and finally sintering the obtained mixture in a high-temperature tubular furnace to obtain a final product which is nickel-cobalt lithium manganate used as a positive electrode material. According to the nickel-cobalt lithium manganate positive electrodematerial, La and Al are co-doped in the nickel-cobalt lithium manganate positive electrode material; the interplanar crystal spacing can be increased, so that the migration of lithium ions can be accelerated; the stability of the lithium-free state of the crystal structure under high voltage can be improved; meanwhile, the crystal lattice volume and the stress expansion can be effectively reduced;the nickel-cobalt lithium manganate positive electrode material has the characteristics of high capacity and excellent cycle performance under high voltage; the disordered-ordered phase change underhigh voltage of the nickel-cobalt lithium manganate positive electrode material can be effectively inhibited; the problem of rapid capacity attenuation of the material in cycle under high voltage is solved, so that the service life of the lithium ion batteries can be prolonged.

Description

technical field [0001] The invention relates to a lithium-ion battery positive electrode material and a preparation method thereof, in particular to a high-voltage lithium-ion battery positive electrode material and a preparation method thereof. Background technique [0002] As one of the key components of lithium-ion batteries, the performance of cathode materials largely determines the performance of lithium-ion batteries. At present, as the market has higher and higher requirements for high energy density battery systems, the specific capacity of cathode materials has become one of the main limiting factors restricting the development of lithium-ion batteries. It is of far-reaching significance to develop and improve lithium-ion batteries. [0003] At present, the mainstream lithium-ion battery cathode materials include lithium cobaltate, lithium manganate, nickel-cobalt lithium manganate, and lithium iron phosphate. However, due to the high cost and poor safety of lith...

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Problems solved by technology

[0004] Purpose of the invention: In response to the above problems, the purpose of the present invention is to provide a nickel-cobalt lithium manganese oxide positive electrode material for high-voltage lithium-ion batteries and a preparation method thereof, so as to improve the performance of the nickel-cobalt lithium manganese oxide positive electrode material in high-voltage cycles. Rapid capacity decay and poor structural stability

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