Hierarchical Lotus-Seedpod-Derived Porous Activated Carbon Encapsulated with NiCoS for a High-Performance All-Solid-State Asymmetric Supercapacitor.

Converting biowaste into carbon-based supercapacitor materials provides a new solution for high-performance and environmentally friendly energy storage applications. Herein, the hierarchical PAC/NiCoS composite structure was fabricated through the combination of activation and sulfuration treatments. The PAC/NiCoS electrode garnered advantages from its hierarchical structure and hollow architecture, resulting in a notable specific capacitance (1217.2 F g at 1.25 A g) and superior cycling stability. Moreover, a novel all-solid-state asymmetric supercapacitor (ASC) was successfully constructed, utilizing PAC/NiCoS as the cathode and PAC as the anode. The resultant device exhibited exceptionally high energy (49.7 Wh kg) and power density (4785.5 W kg), indicating the potential of this biomass-derived, hierarchical PAC/NiCoS composite structure for employment in high-performance supercapacitors.