Binary sodium ion battery positive electrode material as well as preparation method and application thereof

The invention discloses a preparation method of a binary sodium-ion battery positive electrode material in the technical field of sodium-ion battery positive electrode material preparation, which comprises the following steps: (1) heating two metal simple substance materials M and N to a molten liquid state, and cooling to obtain a binary alloy; (2) taking the binary alloy as an anode, taking a material with small electronegativity as a cathode, putting the cathode and the anode into an electrolytic tank, electrolyzing the binary alloy until the binary alloy is dissolved, collecting a precipitated product, and carrying out water washing, alcohol washing, filtering and drying to obtain an alkaline precursor; (3) adding a sodium source into the alkaline precursor, carrying out ball milling to obtain mixed powder, sequentially carrying out pre-sintering and high-temperature sintering on the mixed powder, cooling to room temperature at a constant speed, and taking out to obtain a sintered product; and grinding th