Fabrication of polypyrrole-based film electrodes for supercapacitor application

Supercapacitors are energy storage devices that can be used for hybrid chemical vehicles and power backup supplies. This paper aimed to fabricate polypyrrole-based film electrodes that can be used in such applications. The effect of varying the concentration of sodium p-toluenesulfonate (Na-pTs) used as the dopant in the electrodeposition of the films was also studied. It was established that as the dopant concentration increases, the resistivity of the film decreases thus, the conductivity is higher. The conductivities of the film electrodes at 0.08M, 0.10M, and 0.12M Na-pTs are 105.21 S/cm, 114.66 S/cm, and 151.71 S/cm respectively. The film conductivities were determined via Van der Paw Four-Point system. The film thickness at 0.08M, 0.10M, and 0.12M Na-pTs was acquired using SEM analysis and resulted to an average thickness of 24.8 um. the elemental composition of the film electrode was verified by an EDX spectroscopy. Moreover, it was found that the capacitance of the film electrode increases with respect to the concentration of a strong sodium chloride (NaCl) elecrolyte in a cyclic voltammetry test. The capacitance values were computed to be 0.106 F, 0.117 F, and 0.335 F at 0.10 M, 0.15M, and 0.20M NaCl accordingly. Lastly, a supercapacitor prototype was assembled and it was found out that increasing the organic electrolyte concentration enhanced the discharging time. The longest discharging time was 70 minutes obtained from using 0.20M Na-pTs electrolyte concentration