Abstract The development of cost-effective and efficient energy storage devices, such as supercapacitors with enhanced electrochemical properties, is highly needed for the future. Therefore, the highly porous surface area of wheat straw is activated carbon derived through chemical activation and used to develop electrodes. The activated carbon with a surface area of 1093.46 m2/g was used for electrode fabrication by mixing proportions of 80%, 90%, 100%, and 0% activated carbon, with polyvinylidene fluoride and N-methyl-2-pyrrolidone solution on different current collectors like copper, stainless steel, and aluminum. The electrochemical analysis of the developed electrodes and symmetric electrochemical double-layer capacitors was performed against a silver/silver chloride reference electrode using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The specific capacitance of the electrodes, as shown in cyclic voltammogram curves, is 305.2, 287, and 256.2 F/g. The galvanostatic charge-discharge curves display 281, 244.5, and 226.5 F/g at 0.5 A/g, and 247, 206, and 189 F/g at 1 A/g for copper, aluminum, and stainless steel current collectors, respectively. The symmetric electrochemical double-layer capacitors, made with 90% activated carbon and copper current collectors, exhibited quasi-rectangular curves with specific capacitances of 219.4, 172.7, and 132.4 F/g. Different areas of the current collector in supercapacitors increase the active material deposit, enabling more charge and ions to accumulate, resulting in improved charge transfer resistance.
Kumar et al. (2025) studied this question.