Chemically synthesized 3D nanostructured polypyrrole electrode for high performance supercapacitor applications

Three-dimensional (3D) polypyrrole (Ppy) electrodes are directly grown on Ni foam using a solution-based cost effective chemical method and an in situ controlled precipitation route for supercapacitor application. The Ppy electrodes are characterized for their structural and morphological studies using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy. The XRD study revealed that Ppy electrodes are amorphous. SEM shows the formation of tiny spherical grains spread over the entire electrode surface. The FT-IR study confirms the formation of Ppy film on the electrode surface. The supercapacitive performance of the Ppy electrode using the cyclic voltammetry technique in a 3M KOH electrolyte shows a maximum specific capacitance of 931 F/g at a scan rate of 5 mV/s. Performance analysis of the supercapacitive electrode carried out using electrochemical impedance spectroscopy (EIS). A distorted semicircle in the high frequency region of EIS shows reduction in charge-transfer resistance.