Carbon@NiCo₂S₄ nanorods: an excellent electrode material for supercapacitors

Carbon@NiCo₂S₄ nanorods were synthesized through a facile in situ hydrothermal approach using carbon supported nickel (Ni/C) nanorods as both the template and nickel source. The morphology and electrochemical properties of NiCo₂S₄ can be effectively tuned with carbon nanorods as well as the addition of hydrogen peroxide (H₂O₂) during the hydrothermal process. The carbon nanorod endows NiCo₂S₄ with rod-like morphology and good electrochemical stability during active reversible redox reactions. Moreover, the addition of H₂O₂ creates the porous structure of NiCo₂S₄, improving its electrochemically active surface area greatly, which is beneficial for efficient charge and ion transport in electrodes. Electrochemical measurements indicate that the H₂O₂ treated carbon@NiCo₂S₄ (labeled as C@NiCo₂S₄-H) nanorods present high specific capacitance (1455 F g^-1 at the current density of 1 A g^-1) and excellent cycling stability (83% retention after 2000 cycles). It is believed that other carbon-based composites with superior electrochemical behavior for supercapacitor applications can also be synthesized using the proposed method in this study.