Construction of Moiré-like TiO2/polypyrrole electrodes for high performance photo-assisted supercapacitors

Abstract

There is currently a need for research into using external energy to increase the performance of the supercapacitor in energy storage systems because of their poor energy density. This paper reports the effective creation of photo-assisted supercapacitors with moiré-like morphology using polypyrrole (PPy) and titanium dioxide nano powder to replicate the surface of inexpensive and widely available CD discs. The composite material combines the moiré-like superstructure's strong light trapping property with titanium dioxide's high photo-sensitivity, achieving the aims of boosting light absorption, extending the optical route, and improving capacitor performance under light. By combining morphology construction and external energy interventions to improve capacitor performance, the specific capacitance under light is 509.0 F g−1 at 1 A g−1, 13.1 % higher than the same material without moiré-like morphology (449.9 F g−1). When assemble into a sandwich-structured symmetric supercapacitor, it has an area specific capacitance of 99.42 mF cm−2 and an energy density of 7.28 Wh kg−1 at a power density of 217.4 W kg−1, outperforming typical photo-assisted supercapacitors. The current work suggests a practical and straightforward method for increasing the light absorption efficiency and performance of photo-assisted supercapacitors.