Hierarchical CNT@NiCo2O4 core-shell hybrid nanostructure for high-performance supercapacitors

The mass integration of electrochemically active materials on nanosized conductive fillers is a promising strategy to achieve an ideal electrode structure for energy storage devices. In this research, a one-dimensional CNT@NiCo2O4 nanosheet core-shell structural nanocable was constructed by a facile chemical co-deposition route combined with post-calcination in air. The subsequent thermal treatment led to the transformation of the hydroxide nanosheet precursor to NiCo2O4 nanosheets, during which process the overall morphology and structure were well retained. By selecting CNTs as conductive support for ultra-thin NiCo2O4 nanosheets, a high-performance electrode for supercapacitors was obtained. Notably, the as-prepared CNT@NiCo2O4 nanocables have a high capacitance of 1038 F g(-1) at a current density of 0.5 A g(-1). Furthermore, the specific capacitance of the product was almost 100% retained after 1000 cycles, which indicates excellent structural and cycling stability. More importantly, a relatively high mass loading of active materials on CNTs was also achieved, making the practical application of such electrode materials possible. Consequently, this CNT@NiCo2O4 nanocable is a promising electrode for high-performance supercapacitors.