Electrochemical properties of WO3-reduced graphene oxide composite powders prepared by one-pot spray pyrolysis process

In this work, we report the preparation of WO3-reduced graphene oxide (rGO) composite powders by spray pyrolysis process using a stable graphene oxide colloidal solution with ammonium tungstate. The ultrafine WO3 nanocrystals below 10 nm in size are dispersed within the rGO matrix. The bare WO3 powders prepared from the aqueous spray solution of ammonium tungstate are spherical and do not aggregate. The bare WO3 and WO3-rGO composite powders show monoclinic and cubic crystal structures, respectively. The initial discharge capacities of the bare WO3 and WO3-rGO composite powders at a current density of 100 mA g−1 are 771 and 941 mA h g−1, respectively, and their initial Coulombic efficiencies are 67 and 65%, respectively. The discharge capacities of the bare WO3 and WO3-rGO composite powders at the 300th cycle are 282 and 546 mA h g−1, respectively.