Surfactant-Assisted NiCo2S4 for Redox Supercapacitors

Until now, crystalline NiCo2S4 and its composites have demonstrated improved performance in supercapacitor applications compared to their oxide analogues due to their relatively higher electrical conductivity and multifaceted redox reaction. However, amorphous phase materials have recently shown promise in electrochemical energy storage systems. This work reports on amorphous NiCo2S4 with the help of urea via the hydrothermal method. It was noted that urea not only aided the amorphous formation but also served as a nitrogen precursor. In comparison, amorphous NiCo2S4 demonstrated a higher nitrogen atom% of 5.9 compared to 4.49 for crystalline NiCo2S4. Furthermore, the amorphous NiCo2S4 electrode exhibited superior electrochemical performance, with a specific capacitance of ~3506 F g−1, which was higher than the cNCS electrode’s specific capacitance of ~2185 F g−1 at 2 A g−1. Additionally, aNCS in a two-electrode asymmetric supercapacitor exhibited a specific capacitance and an energy density of ~196 F g−1 and 56 Wh kg−1, respectively.