Abstract
A NiCo(2)S(4)/N-CDs/RGO ternary composite hydrogel was prepared via a one-step hydrothermal method, utilizing lignin-based nitrogen-doped carbon dots as a bridge connecting NiCo(2)S(4) and graphene. The specific capacitance of NiCo(2)S(4)/N-CDs/RGO significantly outperforms that of the GH and NiCo(2)S(4)/RGO electrodes, achieving 1050 F g(-1). The 3D mesh porous hydrogel structure mitigates NiCo(2)S(4) nanoparticle aggregation, providing a larger specific surface area for enhanced charge storage. The abundant functional groups of N-CDs interact with Ni (II) and Co (III) cations, favoring NiCo(2)S(4) particle synthesis. Additionally, an assembled solid-state asymmetric supercapacitor employing NiCo(2)S(4)/N-CDs/RGO as the positive electrode exhibited excellent energy density (68.4 Wh kg(-1)) and cycle stability (82% capacitance retention after 10,000 constant current charge-discharge cycles).