Amorphous Hollow NiCo(OH) x S y Spheres with Improved Electrochemical Performance for Supercapacitor Applications

Supercapacitors demonstrate substantial application prospects in the energy storage domain owing to their high power density, swift charging–discharging capabilities, and prolonged cycle life. However, their relatively low energy density constrains their further advancement. In this study, a double-ligand NiCo(OH) x S y amorphous material with a hollow bulbous morphology was effectively fabricated using a homemade self-sacrificing precursor template. Due to the distinctive amorphous structure and the OH/S dual-ligand synergistic effect, the electrode material exhibited excellent charge storage performance (1912 F g –1 at 1 A g –1 and 79.1% retention at 20 A g –1 ). The asymmetric supercapacitor (NiCo(OH) x S y //PC) achieves a value of 60.97 Wh kg –1 at 375 W kg –1 . After 8000 charge–discharge cycles at 5 A g –1, it showed 88.5% capacity retention and 99.6% Coulombic efficiency. These outstanding electrochemical performances suggest the considerable potential of NiCo(OH) x S y in energy storage devices.