▎ 摘　　要

NOVELTY - Prussian white composite material comprises Prussian white nanoparticles and graphene, where the surface of the Prussian white nanoparticles is completely coated with graphene. The Prussian white nanoparticles coated with graphene are bonded to each other. The particle size of Prussian white composite material is 1-12 mu m. The Prussian white nanoparticle has a size of 10-50nm. USE - Prussian white composite material used for preparing an alkali metal or alkali metal ion battery i.e. sodium ion battery, potassium ion battery or an ammonium ion battery (all claimed). ADVANTAGE - The Prussian white composite material significantly improves the rate performance of the alkali metal ion battery while ensuring high capacity and excellent cycle performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing Prussian white composite material, which involves: (A) dissolving sodium ferrocyanide and an inorganic sodium salt in deionized water, and sufficiently stirring to get solution A; (B) dissolving soluble salt of magnesium(II) cation in deionized water and stirring well to obtain solution B; (C) adding solution B dropwise to the solution A, and carrying out hydrothermal reaction to obtain Prussian white; and (D) mixing Prussian white with graphene to obtain the Prussian white composite material.