Preparation of hollow core-shelled MnCoSex/MnO@nitrogen-doped carbon composite by multiple interfaces coupling and its electrochemical properties

Abstract

Hollow MnCoSex/MnO nanospheres wrapped with nitrogen-doped carbon shell (MnCoSex/MnO@N-C) were prepared via a simple solvothermal and selenization strategy followed by the carbon coating procedure. Benefitting from the multiple interfaces coupling between MnCoSex and MnO and unique hollow core-shell architecture, MnCoSex/MnO@N-C composites possess high specific capacitance and superior rate capability, even at a high current density of 5 A/g, the MnCoSex/MnO@N-C can operate steadily for 20000 cycles with 84.6% of initial specific capacitance maintained. An asymmetric supercapacitor device assembled by MnCoSex/MnO@N-C and active carbon depicts a high energy density of 11.2 W·h/kg at a power density of 810 W/kg and a long cycle life with 84.0% of the initial specific capacitance retained after 20000 cycles.