Fabrication and electrochemical characterization of an aqueous electrolyte-based Mn₂O₃/rGO//WO₃ asymmetric supercapacitor device

Transition metal oxide (TMO) when combined with carbon-based materials, there has been a significant improvement over poor conductivity, inadequate electrode kinetics, and cycle stability. This research reports a facile and inexpensive hydrothermal approach for supercapacitor electrode applications using manganese oxide/reduced graphene oxide (rGO) nanocomposite. Further, hydrothermally made WO₃ nanorods, as negative electrode was implemented in constructing a Mn₂O₃/rGO//WO₃ asymmetric supercapacitor device design to boost its capacitive performance. The asymmetric device demonstrated a specific capacitance of 94 Fg⁻¹ at 0.5 Ag⁻¹, maintained a stable operating potential window at 1.8 V in the 0.1 M K₂SO₄ electrolyte, and still retained 92% of the opening capacitance value after 3000 cycles, indicating very good cycle life. The asymmetric Mn₂O₃/rGO//WO₃ supercapacitor achieved a maximal energy density of 42 Wh kg⁻¹ at a power density of 720 W kg⁻¹. The study’s finding validates redox-active materials to considerably augment the energy storage capacity of supercapacitors in comparison to conventional asymmetric carbon-based negative electrode devices.