Facile one-step synthesized hierarchical Bi₂O₃/Bi₁₂Mn₁₂O₄₄ composite as a long-term stable and high-performance electrode for hybrid supercapacitors

Bimetallic oxides are a promising class of noteworthy electrode materials for supercapacitor (SC) application due to the advantages of relatively large surface area, rich electroactive sites, and high electrical conductivity compared to single transition metal oxides (TMOs). Herein, we report bismuth oxide-bismuth manganese oxide (Bi₂O₃/Bi₁₂Mn₁₂O₄₄ (BBMO)) nanoparticles which were synthesized by adopting a simple solvothermal method. Moreover, the effect of growth time (3, 6, and 9 h) of BBMO materials on their morphology and electrochemical properties was studied systematically. Also, corresponding solitary TMOs were prepared and their electrochemical properties were investigated. Among the prepared electrode materials, the BBMO material synthesized for 6 h (BBMO-6 h) exhibited a superior areal/specific capacity value of 308.7 µAh cm⁻²/140.3 mAh g⁻¹ at 5 mA cm⁻². Additionally, the BBMO-6 h material was used as a positive electrode to construct the hybrid SC (HSC) cell while activated carbon was used as a negative electrode. The constructed HSC cell delivered maximum energy and power density values of 16.7 Wh kg⁻¹ and 1703.3 W kg⁻¹, respectively. Moreover, real-time practical applicability was tested by powering various electronic appliances such as multi-colored light-emitting diodes and a low-rating direct current motor by using the fabricated HSC cell.