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

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)-H₂SO₄ and an organic redox molecule, anthraquinone (PVA-H₂SO₄-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 m²/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-H₂SO₄ gel electrolyte improves the performance of the fabricated device significantly as compared to using pristine PVA-H₂SO₄ or 1 M H₂SO₄ 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.