High‐performance Supercapacitors Enabled by Highly‐porous Date Stone‐derived Activated Carbon and Organic Redox Gel Electrolyte

Abstract Construction of eco‐benign, cost effective, and high‐performance supercapacitors with improved electrolytes and hierarchical porous electrodes is necessary for effective energy storage. In this study, a gel type organic redox electrolyte made of polyvinyl alcohol (PVA)‐H 2 SO 4 and an organic redox molecule, anthraquinone (PVA‐H 2 SO 4 ‐AQ) was prepared by simple solution casting method, and was used to construct a symmetric supercapacitor (SSC) with a date stone‐derived activated carbon (DSAC) having a high BET surface area (1612 m 2 /g). The DSAC was synthesized by simple carbonization method followed by activation with potassium hydroxide. The SSC exhibit a high specific capacitance of 126.5 F/g at 0.5 A/g, as well as a high energy density of 17.5 Wh/kg at a power density of 250 W/kg with high capacitance retention (87%) after 1000 GCD cycles. The present research suggests that adding anthraquinone to a PVA‐H 2 SO 4 gel electrolyte improves the performance of the fabricated device significantly as compared to using pristine PVA‐H 2 SO 4 or 1 M H 2 SO 4 electrolytes. The research also presents a promising approach for the development of sustainable and eco‐benign materials for energy storage applications. The use of date stone waste as a precursor material for activated carbon electrodes presents an opportunity for cost‐effective and sustainable energy storage. Overall, the findings of this research have important implications for the future design and fabrication of high‐performance and cost‐effective supercapacitors.