Mesoporous Mn-substituted Mn_xZn_1−xCo₂O₄ ternary spinel microspheres with enhanced electrochemical performance for supercapacitor applications

Extensive investigations have been carried out on spinel mixed transition metal oxide-based materials for high-performance electrochemical energy storage applications. In this study, mesoporous Mn-substituted Mn_xZn_1−xCo₂O₄ (ZMC) ternary oxide microspheres (x = 0, 0.3, 0.5, 0.7, and 1) were fabricated as electrode materials for supercapacitors through a facile coprecipitation method. Electron microscopy analysis revealed the formation of microspheres comprising interconnected aggregates of nanoparticles. Furthermore, the substitution of Mn into ZnCo₂O₄ significantly improved the surface area of the synthesized samples. The electrochemical test results demonstrate that the ZMC3 oxide microspheres with an optimal Mn substitution exhibited enhanced performance, displaying the largest specific capacitance of 589.9 F g⁻¹ at 1 A g⁻¹. Additionally, the ZMC3 electrode maintained a capacitance retention of 92.1% after 1000 cycles and exhibited a significant rate capability at a current density of 10 A g⁻¹. This improved performance can be ascribed to the synergistic effects of multiple metals resulting from Mn substitution, along with an increase in the surface area, which tailors the redox behavior of ZnCo₂O₄ (ZC) and facilitates charge transfer. These findings indicate that the incorporation of Mn into mixed transition metal oxides holds promise as an effective strategy for designing high-performance electrodes for energy storage applications.