Synergistic Regulation of Polysulfide Shuttle and Lithium Dendrites via Ce-Doped ZIF-8 Based Separators for High-Performance Li–S Batteries

Lithium–sulfur batteries (LSBs) are regarded as a competitive candidate for future energy storage systems due to their exceptionally high theoretical capacity and energy density, but their practical use is limited by severe lithium polysulfides (LiPSs) shuttling and uncontrolled lithium dendrite growth, harming cycling stability and Coulombic efficiency. Herein, a multifunctional Ce-ZIF-8/PDA@PP separator is fabricated via in situ growth. Theoretical and experimental studies confirm it integrates synergistic functionalities from polydopamine (PDA), ZIF-8, and Ce doping. The PDA interlayer, rich in polar groups, enhances electrolyte wettability, homogenizes Li+ flux, acts as a chemical anchor and nucleation facilitator, enabling uniform Ce-ZIF-8 growth on inert PP. ZIF-8 provides uniform microporous channels for size-selective Li+ transport and LiPSs anchoring sites. Redox-active Ce3+/Ce4+ centers enable dynamic electron transfer via 4f–5d orbitals, accelerating LiPSs redox kinetics, enhancing adsorption, and regulating Li+ deposition through local electric field modulation. Consequently, symmetric cells with this separator achieve ultralong stability over 3600 h at 1 mA cm–2/1 mAh cm–2, while full cells cycle stably over 600 cycles at 1 C with 0.040% per cycle capacity decay. This study offers a robust separator strategy to concurrently address polysulfide diffusion and lithium dendrite growth in high-performance LSBs.