Ferromagnetic 1D-Fe3O4@C Microrods Boost Polysulfide Anchoring for Lithium-Sulfur Batteries

A lithium-sulfur (Li-S) battery has become a promising energy storage device because of its remarkable excellent specific capacity density and energy density. However, low sulfur utilization and sharp decay of Coulombic efficiency caused by the "shuttle effect" are still gaps that cannot be filled in the long-term development of Li-S batteries. To break through these bottlenecks, we report a ferromagnetic one-dimensional porous Fe3O4@C (1D-Fe3O4@C) electrode as a sulfur host. Benefitting from its one-dimensional (1D) structure, coated carbon shell, and excellent magnetic properties, the as-prepared electrode, besides enhanced conductivity, has a strong binding effect on polysulfides through the Lorentz force and physical adsorption, thereby reducing the "shuttle effect". At the same time, the porous morphology is conducive to sulfur loading and accommodates the huge volume changes during cycling. The 1D-Fe3O4@C/S electrode shows excellent specific capacity and superior high-rate cyclability, which is demonstrated by capacity retention rates of 95.1 and 92.7% for 200 cycles at 1 and 2 C, respectively.