▎ 摘　　要

NOVELTY - A composite film of reduced graphene oxide coated carbon nanotubes /tin oxide(CNTs/SnO2) with hollow structure is prepared by synthesizing polystyrene microsphere (PS) by micro-emulsion polymerization method, mixing tin(IV) chloride pentahydrate, polystyrene microsphere, hexadecyl trimethyl ammonium bromide, carbon naotubes (CNTs) and deionized water, reacting, cleaning and drying to obtain CNTs/SnO2-PS composite film, mixing with ascorbic acid and graphene oxide, reacting, drying and calcining. USE - The method is used for preparing composite film of reduced graphene oxide coated carbon nanotubes with hollow structure in button cell, specifically as cathode material of sodium ion battery assembled as button battery (all claimed). ADVANTAGE - The film has gap structure that can shorten electron/sodium ion diffusion path and cycle life reaching 1000 cycles even under high current density of 1 A/g showing super-high cycle stability, accelerates reaction kinetics of SIB, provides rich active sites for sodium ion, relieves volume expansion of tin oxide by reduced graphene oxide, and exhibits excellent electrochemical performance.