Carbon soot nanostructures for solid-state supercapacitors

Energy storage remains a pivotal focus within the scientific and power sectors. Solid-state supercapacitors (SSCs) are emerging as a promising solution due to their exceptional power density, extended cycle life, chemical stability, and enhanced safety. Carbon-based materials such as: activated carbon, graphene, carbon nanotube, etc., have been extensively explored for SSCs due to their high conductivity, high surface area, and robustness in acidic or neutral environments. However, the influence of functionalization and thermal annealing of cost-effective combustion-based carbon soot remains insufficiently explored for SSCs development. In this work, we synthesized low-cost mustard oil derived carbon soot using a simple and reproducible combustion method. This study delves into the potential of carbon soot (CS) materials, including Pristine, Functionalized, and Annealed CS as active electrode materials in SSC, utilising a polyvinyl alcohol-H 2 SO 4 membrane as the solid electrolyte. Among all the synthesized materials, Annealed CS based SSC exhibited the best performance, with a specific capacitance of 111 Fg −1 at a scan rate of 5 mVs −1 from the cyclic voltammetry (CV) study and 68 Fg −1 at 0.5 Ag −1 , from the galvanostatic charge-discharge (GCD), it achieved an exceptional energy density of 27 Whkg −1 at 426 Wkg −1 power density. It showed high capacitance retention of 92% over 8000 cycles with 100% coulombic efficiency. These superior properties make annealed CS a promising electrode material for supercapacitors. It enhances energy storage capabilities through its ample surface area, good electrical conductivity, and functional groups that improve electrode wettability and electrolyte ion transport.