Fabrication of high mechanical stability electrodes and bio-electrolytes for high-performance supercapacitor application

Supercapacitors are promising energy storage systems as they offer high cycle stability and high-power density. However, mechanical, and electrochemical stability of the materials especially at high energy rates are the keys to be addressed. In this study, nanocomposites of molybdenum trioxide MoO3 (Mo) and graphene nanosheets (G) besides with carbon nanotube (CNT) were reported as mechanically stable new electrodes for practical use in devices. A low cost, non-aqueous bio-based gel electrolyte (Glycerol, (Gly)/KOH) was used to highlight the electrochemical stability as well as safety. Supercapacitors containing G-Mo20 and CNT-Mo20 electrodes provided an optimum specific capacitance of 474 F g−1 and 468 F g−1, respectively which is at least 4.5 times enhancement compared to carbon-based device. Additionally, the G-Mo20 and CNT-Mo20 devices provided specific energy of 46 Wh kg-1 and 37 Wh kg-1 at a specific power of 280 W kg-1 and 270 W kg−1, respectively. The supercapacitor with G-Mo20 and CNT-Mo20 successfully completed 17,500 charge-discharge cycles, with a capacitance retention efficiency corresponding to 93% and 88% after 30 days. Furthermore, the supercapacitor (diameter of 1.8 cm2) with the electrode G-Mo20 was successfully operated the LED light. A facile fabrication method, flexibility, robustness and safety are the advantages for the devices that can be suggested for wearable electronics.