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 219 F g−1 at a current density of 1.0 A g−1, which is higher than that of pure MnO2 nanosheets (128 F g−1) and PNTs (42 F g−1) in 0.5 m Na2SO4 solution. Meanwhile, the capacitance retention of 86.8 % (after 1000 cycles at 10 A g−1) indicates an excellent electrochemical performance of N‐CNTs@MnO2 prepared in this work.