Facile hydrothermal growth of VO2 nanowire, nanorod and nanosheet arrays as binder free cathode materials for sodium batteries

Abstract

Owing to the natural abundance and low standard potential of sodium, sodium-ion batteries are now considered to be promising power systems for electric vehicles and stationary energy storage. Herein, for the first time, we report the synthesis of VO₂ nanowire, nanobelt and nanosheet arrays with preferential (110) orientation on conductive titanium foil by a simple time-dependent hydrothermal method. The morphological and crystallization evolution processes of these products are investigated via XRD, SEM, Raman and TEM in detail. The effect of VO₂ morphology on sodium storage performance is also probed by charge–discharge and EIS. Benefiting from the unique morphological features, the VO₂ nanowire array shows a superior cycle ability of 160 mA h g⁻¹ after 200 cycles and high rate ability even at 1 A g⁻¹.