Nano-engineering of three-dimensional core/shell nanotube arrays for high performance supercapacitors

Large-scale arrays of core/shell nanostructures are highly desirable to enhance the performance of supercapacitors. Here we demonstrate an innovative template-based fabrication technique with high structural controllability, which is capable of synthesizing well-ordered three-dimensional arrays of SnO2/MnO2 core/shell nanotubes for electrochemical energy storage in supercapacitor applications. The SnO2 core is fabricated by atomic layer deposition and provides a highly electrical conductive matrix. Subsequently a thin MnO2 shell is coated by electrochemical deposition onto the SnO2 core, which guarantees a short ion diffusion length within the shell. The core/shell structure shows an excellent electrochemical performance with a high specific capacitance of 910 F g(-1) at 1 A g(-1) and a good rate capability of remaining 217 F g(-1) at 50 A g(-1). These results shall pave the way to realize aqueous based asymmetric supercapacitors with high specific power and high specific energy. (C) 2013 Elsevier B.V. All rights reserved.