Reutilization of Silver-Impregnated Activated Carbon (SAC) Cartridges with Surface Modification for Supercapacitor Electrodes for Large-Scale Energy-Storage Applications

Abstract

The strategy of converting waste materials into new functional materials is a promising approach for energy-storage applications, particularly in the case of silver-impregnated activated carbon (SAC). SAC, which is typically derived from coconut shells, is primarily used for water purification in home-based filters due to its excellent antibacterial properties. However, the silver concentration is low, and it tends to leach out after a certain period, resulting in waste. To address this issue, SAC was used as a precursor for electrodes in supercapacitor applications. Additional surface treatments, such as heteroatom doping, are also being employed to improve the electrical conductivity and wettability of SAC. Nitrogen was introduced using urea as a precursor to enhance the properties of SAC. XRD analysis confirmed the structural analysis of activated carbon and nitrogen-activated carbon. Morphological analysis revealed the formation of micropores on the surface of the samples. FTIR analysis confirmed the presence of functional groups in the samples. Raman spectra showed the presence of defects after the introduction of nitrogen atoms into the carbon lattice, with higher relative [Formula: see text] compared to AC. Multipoint bet analysis was conducted, and the surface area of the sample was found to be approximately 815[Formula: see text]m2g[Formula: see text], with pore sizes of 810[Formula: see text]m2g[Formula: see text]. Electrochemical analysis was carried out in both three- and two-electrode configurations. The specific capacitance of NAC in cyclic voltammetry and galvanostatic charge–discharge analysis was found to be higher than that of AC because the nitrogen atoms reduced the ionic charge transfer resistance between the electrode and electrolyte surface. Electrochemical impedance spectroscopy (EIS) was also conducted, confirming the solution resistance with 1.5[Formula: see text]Ohm.