Unleashing the Potential: Augmented Supercapacitor Performance of Bi2O3/MnO2@MWCNT Nanocomposites with Redox Additive Electrolyte

The current era’s energy demand emphasizes the necessity of advancements in smart and efficient technologies for the conversion and storage of energy. Thereby, supercapacitors were fabricated based on the nanocomposites (NCs) of Bi2O3/MnO2 (BM) and Bi2O3/MnO2@MWCNT (BMM), and their electrochemical performances were documented. BM and BMM NCs were prepared by a one-pot hydrothermal process. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HR-TEM) analyses were utilized to examine the physicochemical characteristics of the synthesized NCs. Working electrodes were fabricated using BM and BMM NCs and a three-electrode setup was employed to investigate their electrochemical characteristics with 1 M KOH and 0.1 M K4[Fe­(CN)6]-added 1 M KOH (RAE) aqueous electrolytes. In RAE, the BMM NC-modified working electrode attained a maximum specific capacitance of 1768 F g–1 at 10 mV s–1. Subsequently, asymmetrical supercapacitors were fabricated by assembling a cathode consisting of BM- and BMM-modified working electrodes, respectively, and an anode composed of Ni foam modified with rGO. Device performances were evaluated in a two-electrode configuration using KOH and RAE. The BMM NC-based device exhibited energy and power densities of 8.21 Wh kg–1 and 340 W kg–1, respectively, in KOH. These values were enriched to 21.24 Wh kg–1 and 1400 W kg–1, respectively, by the addition of 0.1 M K4[Fe­(CN)6] in KOH. Since the prepared BMM NCs revealed better performances in RAE, the proposed BMM NC and RAE combination served as a better candidate for real-time energy storage applications.