Enhanced performance of multi-dimensional CoS nanoflake/NiO nanosheet architecture with synergetic effect for asymmetric supercapacitor.

Multi-dimensional nanomaterials possess a porous structure and plenty of active sites, so they have promising prospects in supercapacitor applications. As the typical pseudocapacitance materials, interlaced CoS nanoflakes and two-dimensional NiO nanosheets were assembled into multi-dimensional CoS/NiO architectures. The fabricated CoS/NiO nanostructures on nickel foam can directly serve as the supercapacitor electrodes. Such multi-dimensional CoS/NiO architectures exhibit the enhanced electrochemical performances in the light of the cyclic voltammetry curves and galvanostatic charging-discharging (GCD) tests. A multi-dimensional CoS/NiO electrode releases a high specific capacitance of 1620 F g at 1.0 A g, which is distinctly higher than those of pristine CoS and NiO electrodes. The CoS/NiO//nitrogen-doped carbon nanoarrays (NC) asymmetric supercapacitor (ASC) can operate stably at 1.6 V. The GCD curves of the ASC at diverse current densities within the voltage window of 0-1.6 V exhibit reasonable symmetry. The CoS/NiO//NC ASC shows great long-term cycling performance, it has 93.5% capacity retention after 3000 cycles. Electrochemical analyses and detailed material characterizations are performed to reveal the mechanism for the enhanced performance of capacitance.