Chloride Salt‐activated Carbon for Supercapacitors

Much research has gone into the modification and advancement of energy storage devices to meet sustainable and clean energy needs. Since Donald L. Boos patented the electrochemical capacitor in 1970, many studies have been undertaken to develop new and better materials for supercapacitors to tackle the power and energy demands of advanced electronic devices such as smartphones, laptops, tablets, digital cameras, and electric vehicles. High surface areas, good conductivity, low resistivity, and short ion diffusion of carbon-based materials make them ideal electrode materials for supercapacitors. The fast production of biomass worldwide is regarded as the most promising renewable carbon source for the future production of fuels, chemicals, and useful materials. The production from biomass of carbon as the potential electrode for supercapacitor applications demonstrates an improved porous structure with good capacitance and cyclic stability. To enhance the energy storage properties of carbon, it is important to improve its surface area, which can be done by utilizing activation agents such as KOH, K 2 CO 3 , NaOH, and chloride salts. Among these activating agents, chloride salts such as FeCl 3 , ZnCl 2 , NaCl, and many others have been reported to show a vital part in refining the structures of carbon materials mainly by cleaning the surface and generating many pores, which in turn improve the contact between electrolyte and the carbon material. These chloride salts are mostly soluble in nature, so they can be washed off after activating carbon, which creates pores in carbon materials. Using chloride salts as activating agents for improving the supercapacitive performance of activated carbon is a good option because they are less harmful, cost-effective, and easily available.