Rational Design of Asymmetric Spinel/Defect Spinel (ZnMn₂O₄/Cu_1.5Mn_1.5O₄) Nanocomposite-Based Supercapacitor Devices for Efficient Energy Storage with Improved Cycle Stability

The increasing global demand for energy solutions has created the necessity for innovative nanocomposite materials for efficient energy storage applications. This urgency is driving significant advancements in energy storage technologies, raising hope for the future of energy sectors. Supercapacitors (SCs), high-performance electrochemical storage devices, have earned considerable attention to address these challenges. In this article, we have demonstrated a cost-effective, easily obtainable trimetallic spinel/defect-spinel oxide ZnMn 2 O 4 /Cu 1.5 Mn 1.5 O 4 (ZMO/CMO) nanocomposite through a facile one-step solvothermal synthesis process. This nanocomposite demonstrated exceptional charge storage capabilities. The charge storage mechanism was established by using Dunn’s method, which reveals the diffusive nature of the electrode material. The ZMO/CMO nanocomposite exhibits an impressive specific capacitance of 468.1 F/g at 0.5 A/g, with 84% capacity retention even after 20000 cycles, which was attributed to the oxygen vacancies within the defect spinel structure. Moreover, we fabricated an asymmetric device utilizing ZMO/CMO as the cathode and activated carbon (AC) as the anode. This device attained an energy density of 48.1Wh/kg and a power density of 700 W/kg with excellent cycling stability, as mentioned before. Furthermore, our study featured its ability to power a standard LED light.