Construction of hierarchical Mn2O3 hollow microspheres derived from metal–organic frameworks for high performance supercapacitors

Abstract

The application of Mn2O3 in supercapacitors usually faces the problems of poor conductivity and volume expansion during charging and discharging that lead to poor cycling stability. In this study, manganese-based metal−organic frameworks are designed as templates to construct hierarchical Mn2O3 hollow microspheres (Mn2O3-HMS) for supercapacitor electrodes. For a current density of 1 A g−1, Mn2O3-HMS delivers an ultrahigh specific capacitance of 1058 F g−1 comparable to the state-of-the-art results obtained for Mn2O3 composite materials. Moreover, the capacitance retention after 3500 cycles was approximately 90.2% at 10 A g−1. The superb performance of Mn2O3-HMS may be ascribed to the hierarchical structure and synergistic effect of the carbon matrix and oxygen vacancies. The unique structure of Mn2O3-HMS can shorten the electron and ion diffusion pathways and provide abundant redox active sites during cycling, while the carbon matrix and oxygen vacancy improve the charge transfer capability and accelerate the ion diffusion of Mn2O3-HMS. Furthermore, when Mn2O3-HMS is used as the cathode in flexible solid-state hybrid supercapacitors, the device displays an outstanding areal capacitance of 487.86 mF cm−2 at a current density of 1 mA cm−2.