Sculpturing the Core towards Mesoporous Manganese Dioxides Nanosheets-Built Nanotubes for Pseudocapacitance

• Mesoporous MnO2 nanosheets-built nanotubes.
• Facile tunable strategy: sculpture the core in a large scale.
• High specific capacitance: 377.5 F g−1 at current density of 0.25 A g−1.
• Energy density of 22.68 Wh kg−1 and a maximum power density of 4.5 kW kg−1

Ultrathin MnO2 nanosheets-built nanotubes have been fabricated via a large-scale chemical etching method. The diameter and thickness of MnO2 nanotubes can be controlled by fine-tuning the concentration of KMnO4 solution, and the relationship between electrochemical properties and different wall thickness is notably investigated. Besides, the MnO2 nanotubes possess a high surface area of 179.5 m2 g−1 and lots of mesopores. Such unique features are beneficial for providing easy access of the electrolyte to the structure and shortening the diffusion distance of ions. More significantly, recyclable copper ions after etching can be used to synthesize Cu nanowires again. The MnO2 nanotubes in a three-electrode system display much high specific capacitance (377.5 F g−1 at current density of 0.25 A g−1), good rate performance. Moreover, an asymmetric supercapacitor on the basis of MnO2 nanotubes as the positive electrode and activated graphenes (AG) as the negative electrode produced an energy density of 22.68 Wh kg−1 and a maximum power density of 4.5 kW kg−1. These attractive discoveries suggest that it can be an aussichtsreich candidate as an efficient supercapacitive electrode.

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