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.