Sandwich-structured MnO2@N-doped Carbon@MnO2 nanotubes for high-performance supercapacitors

The MnO2@ N-doped carbon@ MnO2 triple-walled nanotubes were synthesized by an in-situ growing of MnO2 nanosheets to both the external and internal surfaces of N-doped carbon nanotubes (NCNTs). Thanks to the unique structures of NCNTs, the density of MnO2 nanosheets were relatively high in the nanocomposite. Because of the NCNTs offered adequate room to accommodate the volume deformation of MnO2 on/in the nanotubes, the final nanocomposites possessed comprehensive electrochemical performance: high specific capacitance (253.1 F/g at a current density of 1 A/g), good rate capability (83.3% retention with charge-discharge rate increasing from 1 A/g to 10 A/g), superior reversibility and cycling stability (96.43% capacitance retention after 2000 cycles at 10 A/g). Based on the above features, the nanocomposites were well fitted for high performance supercapacitors. (C) 2016 Elsevier B.V. All rights reserved.