Shape-controlled synthesis of nickel–cobalt–sulfide with enhanced electrochemical activity

Morphology control of electrode material is critical for high performance supercapacitors. The synthesis of shape-controlled materials is helpful to design advanced electrode materials for supercapacitors. Herein, we prepared two types of NiCo2S4 with nano-bud and nano-mesh morphologies under hydrothermal conditions by facile controlling the reaction time. These materials display morphology-dependent electrochemical activity. Electrochemical measurements showed that the nano-mesh-like NiCo2S4 demonstrate the superior pseudocapacitive performance with a high specific capacitance (3.00 F cm−2 or 1250 F g−1 at 2 mA cm−2) and a favorable rate capability (77.8% from 2 to 25 mA cm−2). Moreover, the specific capacitance remains 80% of its initial value after 5000 cycles even at high current density of 20 mA cm−2. The mesh-like NiCo2S4 also displays a low overpotentials of 299 mV at the current density of 30 mA cm−2, showing better performance in electrochemical oxygen evolution reaction.