Graphene-coated phosphate sodium ion composite positive electrode material and preparation method thereof

The invention discloses a preparation method of a graphene-coated phosphate sodium ion composite positive electrode material in the field of battery materials, which comprises the following steps: dissolving a polyanionic block copolymer in an organic solvent, adding phosphoric acid, and mixing to obtain a block copolymer micelle solution; adding an ethanol solution in which a sodium source is dissolved, an ethanol solution in which metal salt is dissolved and the graphene oxide dispersion liquid into the segmented copolymer micelle solution to obtain a phosphate sodium ion precursor material; and grinding the phosphate sodium ion precursor material, presintering at 200-400 DEG C for several hours, calcining at 600-1000 DEG C in an inert atmosphere, and cooling to obtain the graphene coated sodium ion composite positive electrode material. The graphene-coated sodium ion composite positive electrode material is stable in structure and high in conductivity, meanwhile, the ion transport kinetics of the electrode