Design, fabrication and evaluation of a 1.5 F and 5 V prototype of solid-state electrochemical supercapacitor

The scale-up from a small single cell to a larger stack prototype of a solid-state electrochemical supercapacitor based on polymer electrolyte and activated carbon is demonstrated. The prototype is composed of five single cells stacked in series, has a nominal capacitance of 1.5 F, and a maximum voltage of 5 V. The electrodes of the prototype were prepared using high-surface-area carbon material ~Norit A Supra Eur! and Nafion ionomer. Nafion was used as the electrolyte membrane separator between the electrodes of each single cell and as the binder/ion conductor in the electrodes. The fabricated prototype showed a higher series resistance compared to that estimated in our previous study of a small size single supercapacitor. However, the prototype achieved a specific capacitance of 114 F/g ~referred to the weight of active carbon materials for a single electrode!, which is comparable to the specific capacitance of the previously reported 4 cm2 single-cell supercapacitor. Moreover, an appreciable power density of 1.4 kW/L and a RC-time constant of 0.3 s have been calculated for the device.