Preparation method of modified micro-nano structure sodium ion battery positive electrode material

The invention provides a preparation method of a modified sodium ion battery positive electrode material with a micro-nano structure, which is characterized in that small primary particles are obtained by adopting two-fluid spray drying, the batch stability of the product is easy to control, primary particles with more lattice defects of 30-100nm are formed in the initial stage of sintering, and then primary particles with better crystal form of 50-200nm are obtained by sintering and heat preservation. And the average particle size of secondary particles is 2-5 microns. By coating the nanometer aluminum oxide and penetrating into the surface layer of the material and lattice gaps of the deep filling material, the coating layer is uniformly distributed on the surface of the positive electrode material and is tightly combined, so that the transmission of sodium ions is facilitated; and the obtained aluminum-coated modified micro-nano structure sodium ion battery positive electrode material has relatively high c