Higher-power supercapacitor electrodes based on mesoporous manganese oxide coating on vertically aligned carbon nanofibersElectronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01198a

• Main Authors: Klankowski, Steven A, Pandey, Gaind P, Malek, Gary, Thomas, Conor R, Bernasek, Steven L, Wu, Judy, Li, Jun
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c5nr01198a

A study on the development of high-power supercapacitor materials based on formation of thick mesoporous MnO 2 shells on a highly conductive 3D template using vertically aligned carbon nanofibers (VACNFs). Coaxial manganese shells of 100 to 600 nm nominal thicknesses are sputter-coated on VACNFs and then electrochemically oxidized into rose-petal-like mesoporous MnO 2 structure. Such a 3D MnO 2 /VACNF hybrid architecture provides enhanced ion diffusion throughout the whole MnO 2 shell and yields excellent current collection capability through the VACNF electrode. These two effects collectively enable faster electrochemical reactions during charge-discharge of MnO 2 in 1 M Na 2 SO 4 . Thick MnO 2 shells (up to 200 nm in radial thickness) can be employed, giving a specific capacitance up to 437 F g −1 . More importantly, supercapacitors employing such a 3D MnO 2 /VACNF hybrid electrode illustrate more than one order of magnitude higher specific power than the state-of-the-art ones based on other MnO 2 structures, reaching ∼240 kW kg −1 , while maintaining a comparable specific energy in the range of 1 to 10 Wh kg −1 . This hybrid approach demonstrates the potential of 3D core-shell architectures for high-power energy storage devices. A study on the development of high-power supercapacitor materials based on formation of thick mesoporous MnO 2 shells on a highly conductive 3D template using vertically aligned carbon nanofibers (VACNFs).