Microstructure and Electrochemical Performance of Supercapacitor Based on Nickel/Activated Carbon Composite Electrode

Abstract

Supercapacitors are promising electrochemical energy storage devices because they have higher energy than conventional capacitors and higher power than rechargeable batteries. Based on material for supercapacitors, activated Carbon (AC) has large specific surface area, high conductivity, and chemical stability, but still shows less than optimal specific capacitance and energy density. In this work, AC was composited with nickel (Ni) and Carbon Black (CB) to modify microstructure and optimize its electrochemical performance. Initially, synthesis of Ni-AC (cathode) and AC (anode) slurry was carried out by blending method in different mass percentages of Ni (5, 10, 15, 20, 25 %). The slurry was coated using doctor blade on aluminum foil. Then, Ni-AC//AC was fabricated and tested by Galvanostatic Charge-Discharge (GCD) instrument to analyze the electrochemical performance changes of supercapacitor. Based on XRD pattern, AC peak was found at 26.5° and Ni-AC composite had additional peaks in 44.4°, 51.7°, and 76.2°. The crystal size and porosity of electrode were in range of 23.2 – 45.4 nm and 66.6 – 75.7%, respectively. Based on the electrochemical evaluation, addition of 20% Ni mass in activated carbon electrode has the optimum performance, which increases active sites of the electrode and ion electrolyte adsorption capacity. Further, the GCD revealed that the prepared Ni-AC//AC electrode have excellent capacitive behavior with specific capacitance of 56.6 F/g, power density of 308.8 W/kg, energy density of 20.8 Wh/kg, and specific retention of 69.6% until 50 cycles.