Phytoremediation-inspired biomass-derived hierarchical porous carbon embedded with binary metal sulfide for hybrid supercapacitors

Inspired by phytoremediation, this study proposes a green synthesis strategy integrating biomass conversion with preparation of porous carbon. Taking advantage of the innate ability of plants to enrich metal ions, ions are absorbed and immobilized in vascular tissues. Through pore-forming and sulfidation, a cobalt‑nickel sulfide@bean sprout-derived carbon (CoNiS@BSC) composite is prepared, with sulfides uniformly embedded in hierarchically porous carbon. The impact of activation temperature (700–900 °C) is studied. The 900 °C-activated CoNiS@BSC-900 shows a large specific surface area, optimized hierarchical porous architecture, and high graphitization. As a supercapacitor electrode, it achieves a specific capacitance of 743.61 F·g −1 at 1 A·g −1 . DFT calculations confirm carbon skeleton enhances capacitive behavior via interfacial charge transfer. The assembled CoNiS@BSC-900//BSC hybrid supercapacitor delivers a specific energy of 38.22 Wh·kg −1 at 791.48 W·kg −1 , and retains 94.62% capacitance over 10,000 cycles. This study provides a potential route for linking phytoremediation-inspired biomass conversion with electrochemical energy storage.