Capacity and colour tunability of the electrochromic-supercapacitor electrode based on highly dense rGO-NiO composite nanoflakes

Abstract

In response to the global need for sustainable development and reducing environmental pollution, the search for multifunctional technologies that can both conserve energy and protect the environment has gained momentum. Electrochromic devices have emerged as key energy-saving technologies with the additional capability of energy storage. However, optimizing their performance requires innovative approaches such as morphological tuning, elemental doping, and composite material engineering. Therefore, in this study, we present a simple synthesis method for reduced graphene oxide-nickel oxide (rGO-NiO) nanoflake composites using a hydrothermal process with varying concentrations of rGO. The incorporation of rGO significantly enhances the electrochemical performance of nickel oxide, providing a larger specific surface area, improved electrical conductivity, and synergistic effects that enhance the properties of each component. The optimized composite film, which includes 1 mg of graphene oxide, demonstrates outstanding performance with an areal capacitance of 211.68 mF/cm2, an optical modulation of 71 %, and fast switching speeds of 7.83/7.45 s. These results highlight the significant potential of tailored composite materials to improve the efficiency and stability of electrochromic super-capacitors. This advancement addresses the evolving needs of our dynamic global environment, moving us closer to a sustainable and energy-efficient future.