A three dimensional vertically aligned multiwall carbon nanotube/NiCo₂O₄core/shell structure for novel high-performance supercapacitors

Abstract

Three dimensional (3D) vertically aligned structures have attracted tremendous attention from scientists in many fields due to their unique properties. In this work, we have built the 3D vertically aligned carbon nanotube (CNT)/NiCo2O4 core/shell nanoarchitecture via a facile electrochemical deposition method followed by subsequent annealing in air. The morphology and structure have been in-depth characterized by SEM, TEM, XRD and Raman spectroscopy. Impressively, when used as the electrode material in a 6 M KOH electrolyte, the vertically aligned CNT/NiCo2O4 core/shell structures exhibit excellent supercapacitive performances, including high specific capacitance, excellent rate capability and good cycle stability. This is due to the unique 3D vertically aligned CNT/NiCo2O4 core/shell structures, which support high electron conductivity, large surface area of NiCo2O4 and fast ion/electron transport in the electrode and at the electrolyte–electrode interface. Furthermore, the synthesis strategy presented here can be easily extended to fabricate other metal oxides with a controlled core/shell structure, which may be a promising facile strategy for high performance supercapacitors, and even advanced Li-ion batteries.