Supercapacitor performance with activated carbon and graphene aerogel composite electrodes

Abstract

Thus far, activated carbon (AC) has been the material of choice as practical supercapacitor electrode material. However, graphene can be a better alternative material. This work presents a comprehensive ratio study of AC and Graphene Aerogel (GA) as the sole and composite electrodes. The material and facile-fabricated electrodes were characterized, and the electrochemical performances of the prototypes were correlated and discussed in terms of specific capacitance, internal resistances, cyclic performance, and self-discharge. It was found that 20% GA addition on the AC electrode (GA20 specimen) recorded the highest charge-discharge specific capacitance at 78.9 F/g, which was 4% higher than AC at 75.8 F/g, even though the estimated surface area for the electrode was 20% lower than the pure AC electrode. Further addition of GA wt% decreased the capacitance due to the lack of electrode surface area. The equivalent series resistance (ESR) increased with an increase in GA wt% due to the higher electronic resistance of GA material. AC electrode had the lowest self-discharge among all specimens, which was caused by the deeper ion storage inside the electrode’s pores.