Preparation method of a
cathode material for a doped
manganese-based
sodium ion battery, comprising the following steps: S1: Dissolving one or both of
antimony trioxide and
bismuth trioxide with an acid and subsequently adding a
divalent manganese salt to produce a
mixed metal salt solution; S2: Adding the
mixed metal salt solution to an excess alkaline
oxidizing agent solution for the reaction, and after the reaction is complete, carrying out a
solid-liquid separation to obtain a
solid material, such that
manganese ions are oxidized to manganese dioxide, and
antimony is co-precipitated with the manganese dioxide to a form of
sodium hexahydroxyantimonate, or
bismuth is co-precipitated with the manganese dioxide to a form of
sodium bismuthate, thereby ensuring the homogeneity of doped elements in the
cathode material and achieving atomic-level mixing between the elements; and S3:
Drying the
solid material and subsequent mixing with a sodium source and
sintering of a resulting mixture to obtain the
cathode material for the doped manganese-based
sodium ion battery; wherein, in step S2, the alkaline
oxidizing agent solution is a
sodium hydroxide solution in which one or more of
sodium hypochlorite,
sodium chlorate, and
sodium permanganate are dissolved; wherein, in step S2, the
mixed metal salt solution is added dropwise, the alkaline
oxidizing agent solution always has a pH equal to or greater than 10.5, and one oxidizing agent in the alkaline oxidizing agent solution is always sufficient; and wherein, in step S2, the temperature of the reaction is controlled to between 2 °C and 10 °C.