Mesoporous transition metal oxides quasi-nanospheres with enhanced electrochemical properties for supercapacitor applications

In this report, we obtain mesoporous transition metal oxides quasi-nanospheres (includes MnO₂, NiO, and Co₃O₄) by utilizing mesoporous silica nanospheres as a template for high-performance supercapacitor electrodes. All samples have a large specific surface area of approximately 254–325 m² g⁻¹ and a relatively narrow pore size distribution in the region of 7 nm. Utilization of a nanosized template resulted in a product with a relative uniform morphology and a small particle diameter in the region of 50–100 nm. As supercapacitor electrodes, MnO₂, NiO, and Co₃O₄ exhibit an outstanding capacity as high as 838–1185 F g⁻¹ at 0.5 A g⁻¹ and a superior long-term stability with minimal loss of 3–7% after 6000 cycles at 1 A g⁻¹. Their excellent electrochemical performances are attributed to favorable morphologies with a large surface area and a uniform architecture with abundant pores. The associated enhancement of electrolyte ion circulation within the electrode facilitates a significant increase in availability of Faradic reaction electroactive sites.