High energy density supercapacitive material based on a ternary hybrid nanocomposite of cobalt hexacyanoferrate/carbon nanofibers/polypyrrole

In the proposed work, we present a novel, high performance ternary hybrid nanocomposite material based on cobalt hexacyanoferrate/carbon nanofibers/polypyrrole (CoHCF/CNF/PPY). The nanocomposite is fabricated by in situ oxidative polymerization of pyrrole in presence of CoHCF and CNF utilizing simple, cost effective and environmentally friendly approach. The structural and elemental characterizations of the nanocomposite are carried out by various characterization techniques which revealed formation of PPY layer on CNF surface to which CoHCF nanoparticles are linked. Also, the thermal stability of nanocomposite is found to be increased due to presence of CNF backbone. The electrochemical performances of the nanocomposite are investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques, which resulted into specific capacitance of 512 F g−1 at the current density of 0.5 A g−1. Moreover, it exhibits notable energy density of 102 W h. kg−1 and power density of 628 W kg−1. It also shows capacitive retention up to 87.8% after 2000 cycles indicating excellent cyclic stability. The structural stability of CoHCF framework is maintained due to ion diffusion through the cavities and its combination with interlinking network of PPY chains on the surface of CNF enhances electron transport. This charge storage mechanism is responsible for improved charge storage capacity resulting into high energy density. Thus, proposed ternary hybrid nanocomposite of CoHCF/CNF/PPY can be considered to overcome the gap between supercapacitors and batteries, thus can serve as a promising candidate for the future energy storage technologies.