Method for converting O3 phase to P2 phase of sodium ion positive electrode material and sodium ion positive electrode material

The invention belongs to the field of new energy, and discloses a method for converting O3 phase to P2 phase of a sodium ion positive electrode material, which comprises the following steps: step 1, mixing and firing a sodium source and a precursor of the sodium ion positive electrode material, the molar ratio of sodium in the sodium source to transition metal TM in the precursor being Na/TM = 1.0-1.5; and 2, washing the firing product obtained in the step 1. According to the method, the transition from O3 to P2 phase can be realized on the premise of no doping, and meanwhile, the phase transfer is gradually carried out in a gradient manner, so that stripping is avoided in the circulating process, and the electrochemical effect is further improved. Meanwhile, the invention also provides a sodium ion positive electrode material which is realized based on the method. In addition, the invention also provides the sodium ion positive electrode material with the core-shell structure. 本发明属于新能源领域，公开了一种钠离子正极材料的O3相至P2相