Binderless synthesis of nanoknotnet-like cobalt oxide for supercapacitor application

Transition metal oxides have promising candidates for supercapacitors application owing to its excellent theoretical capacitance, eco-friendly and good redox reaction feature. In this work, Nano-knotnet type cobalt oxide as an electrode material has been synthesized by a cost-effective and simple chemical bath deposition (CBD) method for supercapacitors application. The structural and morphological studies of these electrode materials were evaluated by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. XRD studies showed that the cobalt oxide thin films were well-crystallized, pure, and face-centered cubic phases with average crystallite size 29.64 nm. The electrochemical behaviour of the cobalt oxide electrodes was characterized by using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) in 1 M NaOH aqueous electrolyte. GCD exhibited the maximum specific capacitance 322 F g−1 at a current density of 1 mA cm−2 with 84.16% retention of the specific capacitance value after 10 mA cm−2 current density. The CV and GCD measurements demonstrated binderless cobalt oxide is a promising electrode for supercapacitors application.