Magnetic Field‐Driven NiCo‐3DOMC Modified Separators for Effective Lithium Polysulfide Mitigation and Catalysis

Abstract Lithium‐sulfur batteries (LSBs) face challenges from the shuttle effect of lithium polysulfides (LiPSs) and slow redox kinetics. In this study, a NiCo‐Doped 3D Ordered Mesoporous Carbon (NiCo‐3DOMC) composite material is synthesized using a gel‐crystalline template and sol–gel method to modify polypropylene separators in LSBs. Density Functional Theory calculations and experiment results demonstrate that under a magnetic field, the NiCo‐3DOMC enhances adsorption and catalyzes the conversion of LiPSs, effectively mitigating the shuttle effect and boosting redox kinetics. This improvement is due to the material's porous structure and active catalytic sites. Enhanced by magnetohydrodynamic effects and NiCo spin polarization, the modified separators in LSBs deliver a high initial capacity of 1544.21 mAh g⁻¹ at 0.1 C, maintain superior rate performance at 565.49 mAh g⁻¹ at 3 C, and show prolonged cycling stability with only 0.06% capacity decay per cycle over 470 cycles. Even with a sulfur loading of 3.78 mg cm⁻², an initial capacity of 884 mAh g⁻¹ at 0.2 C is achieved. This approach marks a significant advancement in LSB performance, leveraging magnetic field applications to improve battery technology.