Hollow structured and flower-like C@MnCo2O4 composite for high electrochemical performance in a supercapacitor

Abstract

Binary metal oxide MnCo₂O₄ nanosheets wrapped on a hollow activated carbon shell (C@MnCo₂O₄) were successfully synthesized through a facile hydrothermal method followed by a calcination process. The novel structure of a flower-like C@MnCo₂O₄ composite, which consists in a good conductive carbon shell and well interconnected nanosheets, can efficiently facilitate electrolyte penetration and offers an expedite transport path for ions and electrons. Notably, the large surface of the hybrid composite (347 m² g⁻¹) can provide a large amount of active sites, which evidently accommodates the strain during cycling. Benefiting from this elegant combination and the effectively mesoporous structure, the specific capacitance of the C@MnCo₂O₄ composite can be achieved as high as 728.4 F g⁻¹, which is, to the best of our knowledge, the highest value so far reported for MnCo₂O₄ based electrode materials. In addition, the C@MnCo₂O₄ composite exhibits enhanced rate capability and an excellent cycling stability of 95.9% retention after 1000 cycles at a high current density of 8 A g⁻¹. Therefore, the desirable integrated electrical performance allows it to be a promising electrode material for supercapacitor applications.