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‐Mn 3 O 4 /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.