Uniform Decoration of Vanadium Oxide Nanocrystals on Reduced Graphene‐Oxide Balls by an Aerosol Process for Lithium‐Ion Battery Cathode Material

VO 2 ‐decorated reduced graphene balls were prepared by a one‐pot spray‐pyrolysis process from a colloidal spray solution of well‐dispersed graphene oxide and ammonium vanadate. The graphene–VO 2 composite powders prepared directly by spray pyrolysis had poor electrochemical properties. Therefore, the graphene–VO 2 composite powders were transformed into a reduced graphene ball (RGB)–V 2 O 5 (RGB) composite by post‐treatment at 300 °C in an air atmosphere. The TEM and dot‐mapping images showed a uniform distribution of V and C components, originating from V 2 O 5 and graphene, consisting the composite. The graphene content of the RGB–V 2 O 5 composite, measured by thermogravimetric analysis, was approximately 5 wt %. The initial discharge and charge capacities of RGB–V 2 O 5 composite were 282 and 280 mA h g −1 , respectively, and the corresponding Coulombic efficiency was approximately 100 %. On the other hand, the initial discharge and charge capacities of macroporous V 2 O 5 powders were 205 and 221 mA h g −1 , respectively, and the corresponding Coulombic efficiency was approximately 93 %. The RGB–V 2 O 5 composite showed a better rate performance than the macroporous V 2 O 5 powders.