Effect of different electrolytes on the efficient performance of δ-MnO2 electrode for supercapacitor applications

Herein, delta-MnO2 nanostructures were synthesized via electrodeposition and systematically studied for supercapacitor applications. Structural analysis using X-ray diffraction (XRD) confirmed the formation of delta-MnO2 with a crystallite size of 21.5 nm, while field emission scanning electron microscopy (FESEM) revealed a nanowire morphology with diameters around 22 nm. Transmission electron microscopy (TEM) further validated a thickness range of 22 nm, which is indicative of a high surface area beneficial for charge transport. The porous structure was corroborated by Brunauer-Emmett-Teller (BET) analysis, and Fourier-transform infrared spectroscopy (FTIR) confirmed Mn-O stretching at 522 cm-1. X-ray photoelectron spectroscopy (XPS) highlighted core-level spectra, including Mn oxidation states, underscoring the material's electrochemical activity. Electrodes exhibited superior hydrophilicity in NaOH; validated by contact angle analysis, and delivered a remarkable specific capacitance of 864F/g in 0.1 M NaOH at 5 mV/s, with 81 % retention over 2500 cycles. This study highlights material's exceptional potential for next-generation supercapacitors.