A binder- and conductive-agent-free V2O5 thin film electrode was
fabricated by a facile and cost-efficient cathodic deposition method
directly on stainless steel substrates followed by annealing at 300 C in
air for 1 h. The V2O5 film is approximately 1 mm in thickness and
consists of layer-by-layer stacked nanosheets. When used as
a cathode for sodium ion batteries, the V2O5 thin film electrode
exhibits a high reversible discharge capacity (174 mA h g1 at 200 mA
g1), excellent cycling stability (almost 100% capacity retention over
200 cycles at 1 A g1), and outstanding rate capability (retaining
a capacity of 124 mA h g1 at 5 A g1). Cyclic voltammetric analyses
reveal that pseudocapacity-dominated charge storage of sodium ions
accounts for the superior performance.