In Situ Growth of MnO2 Nanosheets on N-Doped Carbon Nanotubes Derived from Polypyrrole Tubes for Supercapacitors

Nitrogen-doped porous carbon nanotubes@MnO2 (N-CNTs@MnO2) nanocomposites are prepared through the in situ growth of MnO2 nanosheets on N-CNTs derived from polypyrrole nanotubes (PNTs). Benefiting from the synergistic effects between N-CNTs (high conductivity and N doping level) and MnO2 nanosheets (high theoretical capacity), the as-prepared N-CNTs@MnO2-800 nanocomposites show a specific capacitance of 219Fg(-1) at a current density of 1.0Ag(-1), which is higher than that of pure MnO2 nanosheets (128Fg(-1)) and PNTs (42Fg(-1)) in 0.5m Na2SO4 solution. Meanwhile, the capacitance retention of 86.8% (after 1000cycles at 10Ag(-1)) indicates an excellent electrochemical performance of N-CNTs@MnO2 prepared in this work.