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Ultrathin Manganese Dioxide Nanosheets Grown on Mesoporous Carbon Hollow Spheres for High Performance Asymmetrical Supercapacitors

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journal contribution
posted on 17.09.2018, 00:00 by Leicong Zhang, Xuecheng Yu, Lulu Lv, Pengli Zhu, Fengrui Zhou, Gang Li, Rong Sun, Ching-ping Wong
Designing and fabricating the electrochemical active materials with outstanding electrochemical performance is crucial for supercapacitors in applications of energy storage devices. In this study, a structure of ultrathin manganese dioxide (MnO2) nanosheets deposited on the surface of mesoporous carbon hollow spheres (MCHSs) is designed and fabricated through a simple method. MCHSs are served as both substrate materials for growth of MnO2 nanosheets and electrical conductive layer for improving the poor electrical conductivity of MnO2, thus obtaining MCHS/MnO2 with good electrochemical performance. What’s more, the synergy of pseudocapacitance and electrical double-layer capacitance (EDLC) in asymmetrical configuration plays a crucial role in enhancing energy density of assembled supercapacitors. The obtained results exhibit that asymmetrical MCHS/MnO2//MCHS supercapacitor displays large specific capacitance (116.4 F/g at 0.1 A/g) and superior cycling stability (90.3% of capacitance retention after 6000 cycles), and delivers high energy density of 64.6 Wh/kg at power density of 100 W/kg. It has been demonstrated that assembled supercapacitor could be used as a small power supply to light a red LED. This study may provide a feasible method in energy storage applications.