A review on activated carbon's role in next-generation supercapacitors

Supercapacitors have emerged as a promising energy storage technology due to their high-power density, rapid charge/discharge rates, and long cycle life. Among various electrode materials, activated carbon (AC) stands out for its high surface area, tunable porosity, cost-effectiveness, and excellent electrochemical stability. This comprehensive review explores recent advancements in AC-based supercapacitor electrodes, focusing on synthesis methods, structural modifications, and electrochemical performance. The impact of pore structure, surface functionalization, and heteroatom doping on capacitance and charge storage mechanisms is analyzed. Moreover, the modification of AC with conductive polymers, metal oxides, metal sulfides, and other types of carbon-based materials is also reviewed. Some of the issues related to increasing energy density at a reasonable cost of decreased power density and scalability, as well as perspectives on the development of sustainable AC and innovative composite materials, are also presented. This work is expected to contribute to the understanding of supercapacitor electrodes for scientists and engineers in the development of next-generation devices.