The invention discloses a composite positive
electrode material of a
lithium ion battery and a preparation method for the composite positive
electrode material, belongs to a chemical power supply material and a preparation method therefor, solves the problem that the existing
lithium-rich
manganese-based material cladding layer has no electrochemical activity, and by providing a new approach for preparing the cladding layer, solves the problem of degradation of specific capacity and initial coulombic efficiency caused by the
side reaction of the
lithium-rich
manganese-based material. The composite positive
electrode material disclosed by the invention consists of the lithium-rich
manganese-based material and an FeF<3> cladding layer which coats the exterior of the lithium-rich manganese-based material; the preparation method comprises the following steps of adding CTAB into n-
hexanol, heating and stirring, and dividing into three parts averagely; adding Fe(NO<3>)<3>, an NH<4>F water solution and a lithium-rich manganese-based material water phase turbid liquid separately, and mixing the obtained three parts of solutions, standing and reserving and taking a lower
water layer and
solid, performing centrifuging, separating and ethyl
alcohol washing, and
solid purifying; and finally performing
vacuum drying. The
composite material provided by the invention has relatively high initial coulombic efficiency and specific capacity; and by providing an effective approach of material cladding, the FeF<3> nanometer layer can be uniformly dispersed on the surface of the lithium-rich manganese-based material to obtain the uniform cladding layer.