Scalable construction of heteroatom-doped and hierarchical core-shell MnO2 nanoflakes on mesoporous carbon for high performance supercapacitor devices

Highly ordered N,S-codoped mesoporous carbon (NSMC) is fabricated via a sacrificial template method followed by a facile doping reaction. Thanks to the uniform mesoporous channels, NSMC exhibits a high specific capacitance of 298 F g(-1). Moreover, deposition of MnO2 nanosheets onto the mesoporous carbon channels is performed via a solvothermal reaction. By controlling the reaction time, various composites and the corresponding electrochemical performance are obtained. The maximum capacitance of MnO2@mesoporous carbon (MnO2@MC-30) is 310 F g(-1). An asymmetric device using NSMC as the negative electrode and MnO2@MC-30 as the positive electrode is assembled. The assembled supercapacitor can deliver a maximum energy density of 44.0 W h kg(-1) with a high power density of 12 000 W kg(-1) and an outstanding cycling stability of 90% after 5000 cycles. This work combines interfacial methods with mesoporous carbon channels, providing new insights for the design of high-performance electrode materials.