Ultrathin α-Bi₂O₃ Nanosheets Prepared via Hydrothermal Method for Electrochemical Supercapacitor Applications

Monoclinic bismuth oxide nanosheets (α-Bi2O3 NSs) of average thickness 28 nm were successfully synthesized via hydrothermal method. Various characterization techniques such as powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Ramman spectroscopy, UV–vis spectroscopy, and Field Emission scanning electron microscopy (FE-SEM) coupled with Energy dispersive X-ray spectroscopy (EDXS) were employed to investigate the prepared bismuth oxide nanopowder in terms of its structural, morphological and optical properties. Electrochemical measurements of α-Bi2O3 NSs deposited on nickel foam substrate were carried out in a 6 M KOH electrolyte to examine its supercapacitive performance. The α-Bi2O3 NSs based electrode with 90 wt% active material exhibited excellent electrochemical performance with pronounced oxidation and reduction peaks, confirming the pseudocapacitive behavior with a high specific capacitance of 764.5 Fg−1 at 5 mVs−1 scan rate. The electrode also presented good cycling stability of about 69% capacitive retention after 3000 cycles measured at 10 mAcm−2 current density. This enhanced specific capacitance, excellent cycling stability and high specific energy (Es = 164.2 Whkg−1) rendered by the electrode which is attributed to widely open and ultrathin nanosheet like morphology, reveals that such a material is instrumental in energy storage applications.