New Opportunities and Challenges of Separators for Lithium‐Sulfur Batteries

Lithium‐sulfur (Li‐S) batteries attract significant interest owing to sulfur's high theoretical specific capacity, natural abundance, low cost, and environmental friendliness. However, poor cycling and C‐rate performance limit their commercialization. Modified high‐porosity separators offer an efficient approach to enhancing the electrochemical performance of Li‐S cells. Conductive and porous separator coatings and interlayers can simultaneously suppress polysulfide migration, improve sulfur utilization, and facilitate the reutilization of trapped active materials. This review examines the research and development of various separator structures for Li‐S batteries and summarizes the electrochemical performance of cells employing carbon‐, metal oxide‐, and polymer‐coated separators. It also discusses conductive interlayer structures, including carbon‐based, carbon‐metal oxide‐based, and conductive polymer‐based configurations, and their effectiveness in extending cell cycle life. Finally, the article highlights the remaining challenges and emerging opportunities in separator engineering for practical Li‐S batteries.