Abstract
Transition metal sulfides have been considered as promising electrode materials for future super-capacitors due to their spinel structures and environmentally friendly properties. Among these materials, NiCo(2)S(4) compounds exhibit high theoretical specific capacity but poor cycling performance. To address this issue, we synthesize several NiCo(2)S(4) urchin balls. The NCS-1.5 nanospheres demonstrate a specific capacitance of 1352.2 F g(-1) at a current density of 1 A g(-1), and maintain high specific capacity after 10 000 charge-discharge cycles. An asymmetric capacitor assembled with the NCS-1.5 sample as the cathode and activated carbon as the anode achieve an energy density of 45.5 W h kg(-1) at 2025 W kg(-1). The urchin-like nanospheres also facilitate the combination with other materials, providing potential insights for the synthesis of supercapacitor electrode materials.