Asymmetric Supercapacitor Based on NiO and Activated Carbon Monolith from Fibers of Oil Palm Empty Fruit Bunches

摘要

Hybrid supercapacitor or asymmetric cell made of composite electrode consists of nanoparticles NiO (75, 80, 85 wt.%), activated carbon powder (ACP) and PTFE binder (5 wt.%) as cathode paired with porous KOH treated activated carbon monolith (ACM) electrode from oil palm empty fruit bunches as anode have been fabricated. The physical characteristics of composite electrodes have been investigated by field emission scanning electron microscopy (FE-SEM). The density and resistivity of the composite electrodes have been measured and found to be increased with percentage of NiO composition. The supercapacitor performance of both symmetric and asymmetric configuration have been investigated in 6 M KOH electrolyte medium using cyclic voltammetry (CV) and galvanostatic charge discharge (GCD) techniques. The CV results at 1 mV s~(-1) for the asymmetric cell demonstrate that the presence of ACM as an anode can improve the supercapacitor cell performance, as shown by the cell composed of composite electrode that consist 75 wt.% of NiO, which optimally exhibits 164 % increase in the value of C_(sp). The same trend is observed by the GCD results. The GCD results show that the presence of porous ACM electrodes has increase the specific energy value from 0.14 Wh kg~(-1) (without ACM) to 0.24, 0.51 and 0.66 W h kg~(-1), and the specific power from 94.9 to 122.0 W kg~(-1) corresponding to asymmetric cell consist of 75, 80, 85 wt.% of NiO, respectively.