Hierarchical Zn-Co-S Nanowires as Advanced Electrodes for All Solid State Asymmetric Supercapacitors

A facile two-step strategy is developed to design the large-scale synthesis of hierarchical, unique porous architecture of ternary metal hydroxide nano-wires grown on porous 3D Ni foam and subsequent effective sulfurization. The hierarchical Zn-Co-S nanowires (NWs) arrays are directly employed as an electrode for supercapacitors application. The as-synthesized Zn-Co-S NWs deliver an ultrahigh areal capacity of 0.9 mA h cm(-2) (specific capacity of 366.7 mA h g(-1)) at a current density of 3 mA cm(-2), with an exceptional rate capability (approximate to 227.6 mA h g(-1) at a very high current density of 40 mA cm(-2)) and outstanding cycling stability (approximate to 93.2% of capacity retention after 10 000 cycles). Most significantly, the assembled Zn-Co-S NWs//Fe2O3@reduced graphene oxide asymmetric supercapacitors with a wide operating potential window of approximate to 1.6 V yield an ultrahigh volumetric capacity of approximate to 1.98 mA h cm(-3) at a current density of 3 mA cm(-2), excellent energy density of approximate to 81.6 W h kg(-1) at a power density of approximate to 559.2 W kg(-1), and exceptional cycling performance (approximate to 92.1% of capacity retention after 10 000 cycles). This general strategy provides an alternative to design the other ternary metal sulfides, making it facile, free-standing, binder-free, and cost-effective ternary metal sulfide-based electrodes for large-scale applications in modern electronics.