Hollow spherical shell structure sodium ferric sulfate composite positive electrode material, preparation method and sodium ion battery

The invention relates to a sodium ferric sulfate composite positive electrode material with a hollow spherical shell structure, a preparation method and a sodium ion battery, and belongs to the technical field of sodium ion batteries. The composite positive electrode material is of a porous hollow structure, the wall thickness is 1-2 microns, and the composite positive electrode material is formed by closely packing 100-500 nm sodium ferric sulfate primary particles on a carbon nanotube skeleton; the end parts of a small amount of carbon nanotubes are exposed outside the microspheres, and the mass fraction of carbon is 1-15wt.% of that of the sodium ferric sulfate composite positive electrode material; the composite material has a large specific surface area of 4.10-20.91 m < 2 >/g and a large void volume of 0.024-0.108 cm < 3 >/g, and is beneficial to permeation of an electrolyte and increase of sodium ion reaction active sites, so that electrochemical properties such as energy density and cycling stability