Advanced Separator Engineering with MOF and Carbon Nanofiber Cathode for Suppressed Polysulfide Shuttling in Li–S Batteries

ABSTRACT Lithium–sulfur (Li–S) batteries offer high theoretical energy density but are limited by the lithium polysulfide (LiPS) shuttle effect, sluggish redox kinetics, and large volume changes during cycling. A dual‐functional strategy is presented using an indium‐doped copper–cobalt metal–organic framework (In‐doped CuCoMOF) modified separator and a heteroatom‐doped Co nanoparticle–embedded porous carbon nanofiber (Co@PCNF) cathode. The In‐doped CuCoMOF on the Celgard separator improves lithium‐ion transport and suppresses LiPS migration through strong chemical adsorption and catalytic conversion. The Co@PCNF cathode provides a conductive porous structure that accommodates volume variation, enhances sulfur utilization, and maintains electrode stability. The synergistic combination accelerates sulfur redox reactions and improves electrochemical performance. The assembled Li–S battery delivers a high specific capacity of 1145 mAh g −1 at 1 C and retains 1100 mAh g −1 after 500 cycles. A high areal capacity of 6.45 mAh cm −2 is achieved at a sulfur loading of 5.5 mg cm −2 under lean electrolyte conditions. This work demonstrates an effective and scalable approach for designing advanced separators and cathodes for high‐performance Li–S batteries.