Novel Interlayer on the Separator with the Cr₃C₂ Compound as a Robust Polysulfide Anchor for Lithium–Sulfur Batteries

The modification of separators with transition metal compounds is an effective strategy to alleviate the shuttle effect of polysulfides in lithium–sulfur (Li–S) batteries. Herein, a novel interlayer on the separator was designed and prepared by employing Cr-based compounds (Cr₂O₃ and Cr₃C₂), favorable sulfur host materials, as a polysulfide anchor for promoting rate capability and cycling life. Thanks to its specific bonding in the crystal structure, enhanced lithium-ion diffusion dynamics, and better confine function with soluble polysulfides, the Cr₃C₂-modified separator exhibits an improved electrochemical performance as compared to the Cr₂O₃-modified separator, including a high capacity of 544 mA h g^–1 at 5 C, a good capacity retention ratio of about 53.3%, and excellent cycling stability with a low decay rate of 0.063% per cycle at 3 C. It is believed that the positive outcomes will shed light on carbide as a potential competitor for adsorbing polysulfides, as well as supply a facile and effective avenue for expediting practical applications of Li–S batteries.