Exfoliated graphite nanoplatelets–V2O5 nanotube composite electrodes for supercapacitors

Exfoliated graphite nanoplatelet (xGnP) and V2O5 nanotube (VNT) composite electrodes were fabricated and tested as electrodes for supercapacitors. Enhancement of the electrochemical performance of the composite over its component materials was demonstrated using cyclic voltammetry (CV), constant current charge/discharge testing and electrochemical impedance spectroscopy in aqueous and organic electrolytes. The calculated specific capacitance of the composite was 35 F g−1 in the aqueous electrolyte and 226 F g−1 in the organic electrolyte at a scan rate of 10 mV s−1 using a three-electrode system. Asymmetric coin cell devices were fabricated using activated carbon cloth as the positive electrode and xGnP–VNT composite as the negative electrode. The energy and power densities in 1 M LiTFSI were 28 Wh kg−1 and 303 W kg−1, respectively, at a discharge current density of 250 mA g−1.

► V2O5 nanotubes have outer diameter of 10 nm. ► xGnP–VNT used as negative electrode for supercapacitors. ► Improved electrochemical performance of xGnP–VNT compared to individual components. ► Asymmetric coin cell devices gave high energy and power densities.