Polyaniline-cobalt hydroxide hybrid nanostructures and their supercapacitor studies

Abstract

We attempt to demonstrate comprehensive analysis of experimentally obtained adverse supercapacitive performance of cobalt hydroxide (Co(OH)2)-polyaniline (PANI) hybrid nanocomposites (HNs), prepared potentiostatically via electrochemical deposition method, compared to phase pure individual nanostructures. Morphologically amorphous Co(OH)2, PANI and HNs are entirely different from one another. The electrochemical properties of the Co(OH)2, PANI and HNs electrodes have been investigated by cyclic voltammograms, galvanostatic charge-discharge and electrochemical impedance spectroscopy measurements. The specific capacitances of PANI, HNs and Co(OH)2 are found to be 3.06F/g, 215F/g and 868F/g, respectively, at a sweep rate of 10 mV/s in 1.0 M NaOH electrolyte, whereas the stabilities and voltammetric charges, assigned to these electrodes, are 47%, 60% & 55% (after 1000 cycles) and 17.22 mC/cm2, 836.39 mC/cm2 and 1128.73 mC/cm2, respectively. Obtained adverse (inferior) supercapacitive performance values of HNs electrodes have been demonstrated on occurrence of inner and outer charges concept. Our work demonstrates plausible causes for observed smaller supercapacitor performance in hybrid/composite nanostructured electrodes (not a common practice) and useful to researchers working in composite/hybrid symmetric and asymmetric supercapacitor fields.