Cashew Nut Shell Derived Porous Activated Carbon Electrodes for “Water‐in‐Salt” Electrolyte Based Symmetric Supercapacitor

Abstract

AbstractBiomass derived activated carbon has attracted well‐deserved attention in the realm of energy storage applications due to its high porosity and excellent electrochemical properties. In this study, cashew nutshell derived activated carbon (CNSAC) exhibits a highly interconnected and honeycomb like microporous structure with a large specific surface area of 835 m2 g−1 and a high pore volume of 0.4 m3 g−1. These superior structural features of CNSAC facilitate rapid diffusion of electrolyte and improve its electrochemical efficiency, which is desirable for electrode material. Fabrication of symmetrical supercapacitors (SSC) employing water in salt (WIS) electrolyte validates the outstanding electrochemical performance of CNSAC electrode material. WIS based SSC had a remarkable specific capacitance of 110 Fg−1 at a current density of 1 Ag−1 over a wider electrochemical stability window of 0–2 V, suggesting that WIS electrolytes can address the limitations of conventional aqueous electrolytes and have significant potential for diverse supercapacitor applications.