Boosting polysulfides conversion with Fe3O4-loaded carbon derived from willow sawdust for high sulfur loading and lean electrolyte lithium-sulfur batteries

Abstract

Lithium-sulfur batteries (LSBs) suffer from rapid capacity decay due to polysulfide shuttling and sluggish sulfur redox kinetics. To improve the chemical anchored towords LiPSs by sulfur host and enhance the reaction kinetics of LSBs, a catalytic carrier of willow derived carbon loaded with Fe derivative (WDC/Fe) was demonstrated by adjusting heating temperature. The WDC/Fe-7 has hierarchical porous carbon enhancing the sulfur utilization, and the loading Fe3O4 with unfilled Fe 3d orbitals provides catalytic active sites and accelerate the redox of LSBs. The S/WDC/Fe-7 electrode achieves an areal capacity of 6.04 mA h/cm2 under high sulfur loading of 9.16 mg/cm2 and an electrolyte/sulfur ratio of 9 μL/mg, maintaining 81.5 % capacity retention after 200 cycles at 0.5 C. Therefore, the biomass-derived carbon loaded with Fe3O4 as a catalytic for sulfur cathode, promoting the practical application of LSBs under high sulfur loading and lean-electrolyte conditions. © 2025