POLYANION-TYPE SODIUM ION BATTERY POSITIVE ELECTRODE MATERIAL AND PREPARATION METHOD THEREFOR

Disclosed is a polyanion-type sodium ion battery positive electrode material, wherein same is applied in the technical field of sodium ion batteries. The positive electrode material comprises a core layer material and a shell layer material coated on the surface of the core layer material. The core layer material is a polyanion-type ferric sodium pyrophosphate with the formula Na4-βFe2+β /2(P2O7)2, wherein 2/3≤β≤7/8, and the shell layer material is carbon. Compared with the prior art, the positive electrode material has a stable discharge platform of 3.0 V, an excellent electrochemical performance, an excellent cycle performance, a relatively high rate performance and an excellent thermal stability, and is a promising new sodium ion battery positive electrode material. At the same time, the element Fe is used as redox ions, the price of which is extremely low, such that the production cost can be greatly reduced. Moreover, by coating the surface of polyanion-type ferric sodium pyrophosphate with a carbon laye