Nickel oxyhydroxide/zinc hydroxide/rGO as a promising candidate for hybrid energy storage and clean energy generation

Metal hydroxides are the upcoming materials in the field of energy storage applications. In this work, a mixed metal hydroxide-based carbon composite, that is, nickel oxyhydroxide/zinc hydroxide/rGO, was successfully synthesized through single step hydrothermal process. The synthesized material was thoroughly characterized using x-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy and field emission scanning electron microscopy. Detailed electrochemical analysis was performed through cyclic voltammetry, constant current charge-discharge analysis and electrochemical impedance spectroscopy. The material exhibited impressive values of specific capacitance (541 F/g), energy density (75 Wh/kg) and power density (2592 W/ kg). The electrodes were found to be sufficiently robust and reliable. A symmetric storage device was also fabricated using the synthesized composite followed by thorough electrochemical analyses of the same. A flexible piezoelectric nanogenerator was fabricated by impregnating the polymer PVDF with the synthesized composite that yielded an open circuit voltage of similar to 50 V and power density of 3117 W/m(3). This opens up the possibilities of using the developed material in real life applications.