3D honeycomb NiCo2S4 @ Ni(OH)2 nanosheets for flexible all-solid-state asymmetric supercapacitors with enhanced specific capacitance

Hierarchical 3D-porous NiCo2S4@Ni(OH)2 core-shell structure on carbon cloth has been successfully grown through a facile and inexpensive solution process. The interconnected NiCo2S4 flower-like nanosheets serve as a robust conductive scaffold to accelerate ion/electron transportation. Further, the uniform growth of Ni(OH)2 nanopetals over the NiCo2S4 nanosheets enlarge the superficial area for electrochemical reaction, which affords the extra pseudocapacitance. The core-shell hierarchical NiCo2S4@Ni(OH)2 electrodes deliver a remarkably higher specific capacity of 404.2 mAh g−1 at a current density of 2 A g−1. Furthermore, the NiCo2S4@Ni(OH)2//AC asymmetric supercapacitor device delivers a high energy density of 83 W h kg−1 at a power density of 817 W kg−1, and excellent cycle stability of 97% even after 6000 cycles.