Unveiling light-modulated capacitance of sea urchin like δ-MnO2: A smart flexible photocapacitive device

Abstract

Supercapacitors have emerged as an essential component for energy storage applications, providing higher power densities and longer cycle life than batteries. Among various supercapacitor materials, manganese dioxide (MnO₂) has attracted considerable attention because of its abundance, environmental friendliness, and good electrochemical characteristics. In this study, we present a simplistic chemical synthesis route for the fabrication of δ phase of MnO₂ with a sea urchin-like morphology. The synthesized MnO₂ device shows remarkable electrochemical performance with about 90 % of retention. While there has been little investigation into how environmental conditions, such as light, impact the capacitive performance of semiconductor materials. Our research aims to address this gap, and we demonstrated significant 46 % increase in capacitance of MnO₂ when exposed to light. During the study we observed photoresponsivity of MnO₂ electrode, therefore, the electrode could be used as a self-powered photodetector. Finally, we reveal the effectiveness of nanostructured δ-MnO₂ flexible electrodes in symmetrical supercapacitor devices, highlighting the potential of MnO₂-based materials to further energy storage technology with the help of light.