Simple route for the synthesis of supercapacitive Co–Ni mixed hydroxide thin films

Facile synthesis of Co–Ni mixed hydroxides films with interconnected nanoparticles networks through two step route is successfully established. These films have been characterized by X-ray diffraction (XRD), Fourier transform infrared technique (FTIR), scanning electron microscopy (SEM) and wettability test. Co–Ni film formation is confirmed from XRD and FTIR study. SEM shows that the surface of Co–Ni films is composed of interconnected nanoparticles. Contact angle measurement revealed the hydrophilic nature of films which is feasible for the supercapacitor. The electrochemical performance of the film is evaluated by cyclic voltammetry, and constant-current charge/discharge cycling techniques. Specific capacitance of the Co–Ni mixed hydroxide electrode achieved 672 F g−1. Impedance analysis shows that Co–Ni mixed hydroxide electrode provides less resistance for the intercalation and de-intercalation of ions. The Co–Ni mixed electrode exhibited good charge/discharge rate at different current densities. The results demonstrated that Co–Ni mixed hydroxide composite is very promising for the next generation high performance electrochemical supercapacitors.