▎ 摘　　要

NOVELTY - A selenium-coated nanocomposite material contains selenium, tin dioxide comprising tetragonal tin dioxide and orthorhombic tin dioxide and graphene. The selenium-coated nanocomposite material is prepared by growing tin dioxide on two different crystal phases to form nanoscale particles, uniformly bonding nanoscale particles to the three-dimensional conductive graphene surface, and uniformly coating disordered selenium on the tin dioxide/graphene nanostructured surface. USE - The selenium-coated nanocomposite material is useful for preparing sodium ion battery electrode material (claimed). ADVANTAGE - The selenium-coated nanocomposite material has excellent storage performance and synergistic effect. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation method of selenium-coated nanocomposite material, which involves adding 2.48 g L-tartaric acid to 50 ml deionized water, adding 295 mu l anhydrous stannic chloride to the solution, adding 150 mg graphene oxide aqueous solution and stirring, continuously stirring, dripping 50 ml 0.1-0.8 mg/ml-1 sodium borohydride solution in the suspension and ultrasonically processing for 3-7 hours, centrifuging, washing the suspension with deionized water and absolute ethanol and vacuum drying at 80 degrees C to obtain tin intermediate product, uniformly mixing selenium powder with tin intermediate product, and calcining at 300-700 degrees C for 3-8 hours.