Photo-Rechargeable Asymmetric Supercapacitors Exceeding Light-to-Charge Storage Efficiency over 21% under Indoor Light

Abstract

Photo-rechargeable energy storage devices are appealing for substantial research attention because of their possible applications in the Internet of Things (IoT) and low-powered miniaturized portable electronics. However, due to the incompatibility of the photovoltaics and energy storage systems (ESSs), the overall light-to-storage efficiency is limited under indoor light conditions. Herein, a porous carbon scaffold MnO-Mn3O4/C microsphere-based monolithic dye-sensitized photo-rechargeable asymmetric supercapacitor (DSPC) is fabricated. The integrated DSPC has a high areal specific capacitance of 281.9 mF cm−2 at the discharge rate of 0.01 mA cm−2. The light-to-electrical conversion efficiency of the DSSC is 27.6% under the 1000 lux compact fluorescent lamp (CFL). The DSPC shows an outstanding light-to-charge storage efficiency of 21.6%, which is higher than that reported ever. Furthermore, the fabricated polymer gel electrolyte-based quasi-solid state (QSS) DSPC shows similar overall conversion efficiency with superior cycling capability. This work shows a convenient fabrication process for a wireless power pack of interest with outstanding performance.