Core-shell coaxially structured NiCo2S4@TiO2 nanorod arrays as advanced electrode for solid-state asymmetric supercapacitors.

An integrated electrode of core-shell coaxially structured NiCo2S4@TiO2 nanorod arrays/carbon cloth (NiCo2S4@TiO2@CC) have been fabricated, via a two-step hydrothermal method. Comprehensive structural and compositional analyses are performed to understand the effects of the NiCo2S4 shell on the TiO2 core. Such core-shell arrays structure can significantly provide abundant electroactive sites for redox reactions, convenient ion transport paths, and favorable structure stability. The NiCo2S4@TiO2@CC electrode represents a splendid specific capacitance (650 F g-1 at 1 A g-1) and enhanced cycling stability (capacitance retention of 97% over 10000 cycles at 5 A g-1). Additionally, the assembled NiCo2S4@TiO2@CC //CNT@CC solid-state asymmetric supercapacitors exhibit a maximal energy density of 0.6 mWh cm-3 at 32.4 W cm-3, and topping cycling stability (85% capacitance retention after 5000 cycles at 5 mA cm-2). The results demonstrate that the well-designed NiCo2S4@TiO2@CC presented in this work are applicable for the development of electrode materials in energy storage devices.