A single step synthesized Co 3O 4–polyindole composite electrode exhibits high specific capacitance, rate performance and cyclability. This enhanced electrochemical supercapacitive behavior is mainly attributed to the synergistic effect between Co 3O 4 and polyindole.
In this paper, we demonstrate a single step synthesis of cobalt oxide – conducting polyindole (Co 3O 4–Pind) composites by in-situ cathodic electrodeposition. The structural and morphological changes of the as-prepared Co 3O 4–Pind composites have been investigated using various techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman analysis and X-ray photoelectron spectroscopy (XPS). Very interestingly, polyindole decoration over Co 3O 4 results in concomitant change in morphology leading to substantial improvement in the supercapacitor behavior. The electrochemical performance of Co 3O 4–Pind has been investigated by cyclic voltammetry, galvanostatic charge–discharge cycling and impedance analysis. The specific capacitance (SC) of Pind decorated Co 3O 4 is found to be 1805 F g −1 at a current density of 2 A g −1 with excellent rate capability (SC: 1625 F g −1 at a high current density of 25 A g −1) and cycling stability. This remarkable supercapacitive performance of the Co 3O 4–Pind composite is mainly attributed to the synergism that evolved between Co 3O 4 and Pind. More importantly, these electrodes are free from binders and conductive carbon which have significant impact over the gravimetric energy density of the devices.