BiFeO 3 Coupled Polysulfide Trapping in C/S Composite Cathode Material for Li-S Batteries as Large Efficiency and High Rate Performance.

We demonstrated the efficient coupling of BiFeO₃ (BFO) ferroelectric material within the carbon–sulfur (C-S) composite cathode, where polysulfides are trapped in BFO mesh, reducing the polysulfide shuttle impact, and thus resulting in an improved cyclic performance and an increase in capacity in Li-S batteries. Here, the built-in internal field due to BFO enhances polysulfide trapping. The observation of a difference in the diffusion behavior of polysulfides in BFO-coupled composites suggests more efficient trapping in BFO-modified C-S electrodes compared to pristine C-S composite cathodes. The X-ray diffraction results of BFO–C-S composite cathodes show an orthorhombic structure, while Raman spectra substantiate efficient coupling of BFO in C-S composites, in agreement with SEM images, showing the interconnected network of submicron-size sulfur composites. Two plateaus were observed at 1.75 V and 2.1 V in the charge/discharge characteristics of BFO–C-S composite cathodes. The observed capacity of ~1600 mAh g⁻¹ in a 1.5–2.5 V operating window for BFO₃₀-C₁₀-S₆₀ composite cathodes, and the high cyclic stability substantiate the superior performance of the designed cathode materials due to the efficient reduction in the polysulfide shuttle effect in these composite cathodes. [ABSTRACT FROM AUTHOR]