Nitrogen-doped carbon/NiCo2S4 aerogel nanocomposite for solid-state supercapacitors

The conversion of biomass into valuable carbon materials reduces environmental pollution and develops effective porous carbon electrodes for energy storage devices. This study aims to prepare a novel composite material consisting of NiCo2S4 and chitosan-derived carbon (CNNA) for use in high-performance supercapacitors. The prepared CNNA composite exhibited a high specific surface area of more than 27 m2/g. The CNNA electrode delivered a high specific capacitance of 1282 F.g-1 at 1.0 A.g-1, significantly surpassing that of bare NiCo2S4 (340 F.g-1) under the same conditions. Electrochemical analysis revealed that the charge storage behavior involved both capacitive and diffusion-controlled contributions, with the capacitive contribution increasing at higher scan rates. Furthermore, a solid-state asymmetric supercapacitor (ACCS//CNNA) was assembled using CNNA as the positive electrode and chitosan-derived carbon aerogel (ACCS) as the negative electrode. The device achieved a specific capacitance of 199 F.g-1, an energy density of 62 Wh.kg-1, and a power density of 750 W. kg-1, and retained 90.9 % of its initial capacitance after 10,000 charge-discharge cycles. These results clearly demonstrate the synergistic effect of NiCo2S4 and N-doped carbon aerogel, highlighting the potential of CNNA as a sustainable and efficient electrode material. Using chitosan in NiCo2S4/carbon composites offers advantages, including nitrogen self-doping, the formation of a uniform nanostructure, and enhanced electrochemical performance compared to composites made from other biomass sources.