Fabrication and electrochemical evaluation of ZnO-Based electrode materials in different electrolytes for supercapacitor applications
摘要
The present study reports the fabrication of ZnO-based electrode materials synthesised via a hydrothermal method and evaluates their electrochemical performance in different electrolytes for supercapacitor applications. X-ray diffraction (XRD) analysis confirmed that pristine ZnO crystallises in the hexagonal wurtzite phase with space group P6₃mc (No. 186). Scanning electron microscopy (SEM) revealed a flower-like hierarchical morphology composed of interconnected nanorods, while energy-dispersive X-ray spectroscopy (EDS) verified the elemental composition. BET analysis revealed a remarkably high specific surface area of 449.71 m2 g− 1, with a mean pore diameter of 3.507 nm, indicative of a mesoporous structure. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the characteristic ZnO stretching vibrations along with surface functionalities retained from CTAB-assisted synthesis. Electrochemical performance was evaluated using 6 M electrolytes of NaOH, KOH, and LiOH. Among these, the NaOH electrolyte demonstrated superior capacitive behaviour, delivering a specific capacitance (Cs) of 114.02 F g− 1 at a current density of 1 A g− 1 and 134.09 F g− 1 at a scan rate of 1 mVs− 1. Moreover, the electrode exhibited excellent cycling durability, retaining 62.26% of its initial capacitance and maintaining a Coulombic efficiency of 98.04% after 8000 galvanostatic charge-discharge (GCD) cycles.