1.5 V Symmetric supercapacitor device based on hydrothermally synthesized Carbon nanotubes and Cobalt Tungstate nanocomposite electrodes

This study reports the hydrothermal synthesis and electrochemical performance of Cobalt Tungstate (CoWO4) and Carbon nanotubes and Cobalt Tungstate nanocomposite (CNT-CoWO4) as supercapacitor electrode material. The active materials are directly deposited on carbon cloth substrates to fabricate binder free electrodes which exhibited specific capacitance of 1443 F g-1 and 1486 Fg-1 at 5 mVs−1 scan rate for CoWO4 and CNT-CoWO4 samples, respectively. As a result of increase in potential window (1 V for nanocomposite CNT-CoWO4 as compared to 0.6 V for CoWO4) and higher specific capacitance in three electrode system, CNT-CoWO4 electrode delivers higher energy density than the CoWO4 electrode. A symmetric capacitor is fabricated from CNT-CoWO4 nanocomposite electrodes. The performance of symmetric capacitor, operated within a potential window of 1.5 V, is comparable to the asymmetric devices. Furthermore, the device delivered maximum energy density of 12 W h kg−1 at 432 W kg-1 power density.