NiCo2S4/CuCo2S4 Composite Cathode Materials for High-Performance Supercapacitors

Abstract

Transition metal sulfides are considered as good electrode materials for supercapacitors due to their high specific capacity and good structural stability. However, its poor multiplicative performance and limited cycle life limit its wide application. To solve this problem, we synthesized NiCo2S4/CuCo2S4 bimetallic sulphide nanocomposites by combining NiCo2S4 with CuCo2S4 using a two-step hydrothermal method. Compared with NiCo2S4 and CuCo2S4 alone, the NiCo2S4/CuCo2S4 nanocomposites have higher specific capacity and better cycling stability as supercapacitor electrodes. The specific capacity value of the NiCo2S4/CuCo2S4 electrodes at 1 A g-1 is 830.3 C g-1 with a potential window of 0-0.5 V. The NiCo2S4/CuCo2S4 nanocomposites are used as the electrodes in supercapacitors. Ni3S4 and activated carbon as cathode and anode, respectively, the hybrid supercapacitor (HSC) assembled with NiCo2S4/CuCo2S4 electrodes has a capacitance value of 129.4 F g-1 at 1 A g-1 and an energy density of up to 52.9 Wh kg-1 at 410 W kg-1. Long-term electrochemical stability tests show that the retention of the electrochemical specific capacity is 54% after 16,000 cycles.