Solvothermal synthesis of novel pod-like MnCo2O4.5 microstructures as high-performance electrode materials for supercapacitors

MnCo₂O_4.5 pod-like microstructures were successfully prepared through an initial solvothermal reaction in a mixed solvent containing water and ethanol, and combined with a subsequent calcinations treatment of the precursors in air. The total synthetic process was accomplished without any surfactant or template participation. The MnCo₂O_4.5 pods possessed a specific surface area as high as 73.7 m²/g and a mean pore size of 12.3 nm. The electrochemical performances were evaluated in a typical three-electrode system using 2 M of KOH aqueous electrolyte. The results demonstrated that such MnCo₂O_4.5 pods delivered a specific capacitance of 321 F/g at 1 A/g with a rate capability of 69.5% at 10 A/g. Moreover, the capacitance retention could reach 87% after 4000 cycles at 3 A/g, suggesting the excellent long-term cycling stability. Furthermore, the asymmetric device was fabricated by using MnCo₂O_4.5 porous pods as anode and active carbon as cathode. It could deliver a specific capacitance of 55.3 F g⁻¹ at 1 A g⁻¹ and an energy density of 19.65 W h kg⁻¹ at a power density of 810.64 W kg⁻¹. Such superior electrochemical behaviors indicate that the MnCo₂O_4.5 pods may be served as a promising electrode material for the practical applications of high-performance supercapacitors. The current synthesis is simple and cost-effective, and can be extended to the preparation of other binary metal oxides with excellent electrochemical properties.