Enhanced rate and cycling performances of hollow V2O5 nanospheres for aqueous zinc ion battery cathode

Vanadium pentoxides (V2O5) show potential in aqueous zinc ion batteries (AZIBs) originating from their layered structure and high theoretical capacity. However, most of the reported V2O5 cathodes suffer from rapid capacity decay and sluggish Zn2+ diffusion kinetics. Herein, hollow V2O5 nanospheres with a diameter of about 450 nm and shell thickness of 50 nm were constructed via a template-free solvothermal method combined with subsequent calcination treatment. The nano-sized hollow structure can not only alleviate the structural stress upon cycling, but also provide shortened ion and electron transport paths, and enhance the surface capacitive behavior. When applied as cathode for AZIBs, it delivers ultrahigh reversible capacity (327 mAh g−1 at 0.1 A g−1), superior rate performance (146 mAh g−1 at 20 A g−1), and excellent cyclic performance (147 mAh g−1 after 6000 cycles at 10 A g−1; 122 mAh g−1 after 10,000 cycles at 15 A g−1), showing clear superiority over commercial V2O5 with irregular appearance. Such attractive capabilities demonstrate that hollow V2O5 nanospheres are a prospective cathode material for AZIBs.