Electrochemical Effect of Cokes-Derived Activated Carbon with Partially Graphitic Structure for Hybrid Supercapacitors

Abstract

We report the optimized electrochemical performance of a hybrid supercapacitor constructed with cokes-derived activated carbon (CAC) and Li4Ti5O12/carbon nanotube (LTO/CNT), which has improved capacitance and rate capability. The improved capacitance of the CAC is attributed to additional shallow intercalation due to the remaining graphitic structure with ion adsorption via optimized surface area and pore structure. The graphitic structure is partially maintained via adjusted KOH activation conditions. The improved rate capability of LTO/CNT is affected by the increase in electronic conductivity, which entails the formation of an electron pathway via a 3D CNT network, whereas nanosized LTO arrangements are embedded in the CNT structure. The maximum energy and power densities of the hybrid supercapacitor are 69.1 Wh kg(-1) and 16.5 W kg(-1), respectively, whereas the cycle-life performance is 88 % after 8000 cycles. This hybrid supercapacitor can allow for the expansion of the application of supercapacitors.