Interconnected NiS-nanosheets@porous carbon derived from Zeolitic-imidazolate frameworks (ZIFs) as electrode materials for high-performance hybrid supercapacitors

Nickel sulfide-based materials have shown great potential for electrode fabrication owing to their high theoretical specific capacitance but poor conductivity and morphological aggregation. A feasible strategy is to design hybrid structure by introducing highly-conductive porous carbon as the supporting matrix. Herein, we synthesized hybrid composites consisting of interconnected NiS-nanosheets and porous carbon ([email protected]) derived from Zeolitic-imidazolate frameworks (ZIFs) using a facile low-temperature water-bath method. When employed as electrode materials, the as-prepared [email protected] nanocomposites present remarkable electrochemical performance owing to the complex effect that is the combined advantages of double-layer capacitor-type porous carbon and pseudocapacitor-type interconnected-NiS nanosheets. Specifically, the [email protected] nanocomposites exhibit a high specific capacitance of 1827 F g−1 at 1 A g−1, and excellent cyclic stability with a capacity retention of 72% at a very high current density of 20 A g−1 after 5000 cycles. Moreover, the fabricated hybrid supercapacitor delivers 21.6 Wh kg−1 at 400 W kg−1 with coulombic efficiency of 93.9%, and reaches 10.8 Wh kg−1 at a high power density of 8000 W kg−1, along with excellent cyclic stability of 84% at 5 A g−1 after 5000 cycles. All results suggest that [email protected] nanocomposites are applicable to high-performance electrodes in hybrid supercapacitors and other energy-storage device applications.