Oxygen vacancies enhance lithium storage performance in ultralong vanadium pentoxide nanobelt cathodes.

ABSTRACT

Ultralong V2O5 nanobelts have been successfully synthesized by a facile hydrothermal oxidation route. Oxygen vacancies are generated in the V2O5 nanobelts by annealing under N2 atmosphere at an elevated temperature. The microstructure and chemical composition of the pristine and annealed V2O5 nanobelts are studied by different methods. Compared to the pristine V2O5 nanobelts, the annealed V2O5 nanobelts sample possesses a higher reversible capacity of 177.8 mAhg-1 after 50 cycles at a current density of 0.3 Ag-1, corresponding to ∼0.27% capacity loss per cycle. At a higher current density of 1.2 Ag-1, the reversible capacity of annealed V2O5 electrode can reach 128.5 mAhg-1, which is two times larger than that of pristine V2O5 electrode. Ultralong flexible morphology together with oxygen vacancies in the annealed V2O5 electrode is considered to be responsible for the enhanced lithium storage properties.