Integration of mesoporous nickel cobalt oxide nanosheets with ultrathin layer carbon wrapped TiO2 nanotube arrays for high-performance supercapacitors

Decorated TiO2 nanotube array-based electrodes for supercapacitors are successfully fabricated by a facile and green process in this paper. Firstly, TiO2 nanotube arrays are modified with ultrathin carbon layers by in situ pyrolysis with residual ethylene glycol from anodization as a carbon resource, then electroactive materials, nickel cobalt oxides with different stoichiometric nickel and cobalt contents, are synthesized by chemical bath deposition and a controlled post-calcination process. The sample demonstrates a superb specific capacitance of 934.9 F g(-1) at a current density of 2 A g(-1) and a better rate capability of 865.8 F g(-1) at 20 A g(-1) while maintaining 92.6% capacity after 5000 cycles at a high current density of 10 A g(-1). The outstanding supercapacitive performance is attributed to the unique hierarchical mesoporous architectures and the desirable design of the nanocomposites, and it also suggests that carbon modified TiO2 nanotube arrays decorated with nickel cobalt oxides are promising candidates for supercapacitor applications.