Facile synthesis of flower-like Bi2O3 as an efficient electrode for high performance asymmetric supercapacitor

Herein, we report a facile, economic, efficient and binder-free strategy to synthesize a flower-like Bi2O3 thin films on flexible stainless steel mesh (FSSM) substrates by rotational chemical bath deposition (R-CBD) approach. The flower-like Bi2O3/FSSM exhibits a monoclinic α-Bi2O3 phase demonstrating the mesoporous nature with a 58.69 m2 g−1 specific surface area. The Bi2O3/FSSM electrode exhibits specific capacitance of 421.76 F g−1 and specific capacity of 674.8 C g−1 at 10 mA cm−2 current density, remarkable cycle stability (60% up to 1000 cycles), and high energy density (149.95 Wh kg−1) with power density (963.85 W kg−1) in 6 M KOH electrolyte. The results indicate that the 6 M KOH is optimized concentration for Bi2O3/FSSM electrodes. An aqueous asymmetric supercapacitor (ASC) device is fabricated by activated carbon (AC) as cathode and Bi2O3/FSSM as an anode. The assembled Bi2O3||AC ASC device exhibits a specific capacitance of 36.37 F g−1 at a current density of 1 mA cm−2 with the energy density (ED) of 18.24 Wh kg−1 at a power density (PD) of 1008.67 W kg−1 and 83.67% capacitance retention after 1000 cycles at the current density of 2 mA cm−2. The derived Bi2O3/FSSM served as a binder-free electrode that provides potential application for electrochemical energy storage devices.