Electrolyte impact on supercapacitors made off Ni2O3-Ni2S3 decorating graphitic carbon nitride

Abstract Utilizing the hydrothermal method, we have successfully synthesized a promising composite material by adorning Ni2O3-Ni2S3 onto graphitic carbon nitride (G-C3N4). This composite's structural and morphological characteristics were thoroughly examined through various analytical parameters. SEM and TEM images clearly depict the incorporation of Ni2O3-Ni2S3 onto the 2D sheets of G-C3N4. Employing this nanocomposite, we have fabricated a supercapacitor with symmetric electrodes. Whatman filter paper, saturated with different electrolytes—0.5 M HCl, 0.5 M Na2SO4, and 3 M KOH—separated the electrodes. A series of tests were conducted to assess the electrical performance of the supercapacitor, including charge/discharge cycles, cyclic voltammetry, impedance, and lifetime measurements. At a current density of 0.3 A/g, distinct charge and discharge times were observed for each electrolyte: 790 s for HCl, 140 s for Na2SO4, and 358 s for KOH. The supercapacitor's specific capacitance (CS) and energy density (E) exhibited variations depending on the electrolyte employed. Optimal performance was achieved with HCl, corresponding to CS and E values of 766 F/g and 84.8 W.h.kg-1. Conversely, Na2SO4 showed reduced values at 106 F/g and 9.5 W.h.kg-1, while KOH resulted in the lowest values of 41 F/g and 5.5 W.h.kg-1. The results unmistakably establish that the supercapacitor's performance adheres to the HCl > Na2SO4 > KOH sequence concerning the electrolytes used. Looking ahead, our team aims to advance toward developing a prototype for a supercapacitor, positioning it as a viable alternative to traditional batteries in energy storage applications.