Adjusting electrode initial potential to obtain high-performance asymmetric supercapacitor based on porous vanadium pentoxide nanotubes and activated carbon nanorods

Abstract

In this work, a high-performance asymmetric supercapacitor has been developed by using porous vanadium pentoxide (V2O5) nanotubes as positive electrode and activated carbon nanorods as negative electrode in an aqueous 2 M LiNO3 electrolyte. To maximize the energy density of the asymmetric supercapacitor, the initial potentials of work electrodes are tuned to different values (0 V, −0.1 V, −0.2 V, and −0.3 V vs. SCE), and the influence of the electrode potential on the electrochemical properties of the obtained asymmetric supercapacitor has been investigated in depth. The results show that −0.2 V is the optimal initial electrode potential. At this initial electrode potential, the built V2O5//C asymmetric supercapacitor could be cycled reversibly in the voltage region of 0–1.8 V, and exhibits high energy and power density (46.35 Wh kg−1 at 1.8 kW kg−1 and 18 kW kg−1 at 28.25 Wh kg−1). Furthermore, the supercapacitor shows excellent cycling stability, with an almost 100% specific capacitance retention after 10,000 cycles. The satisfactory results demonstrate that the adjusting of electrode potential is a very effective method to improve the electrochemical performance of asymmetric supercapacitors.