A Separator with Double Layers Individually Modified by LiAlO₂ Solid Electrolyte and Conductive Carbon for High-performance Lithium–Sulfur Batteries

The “shuttle effect” and the unchecked growth of lithium dendrites during operation in lithium–sulfur (Li–S) batteries seriously impact their practical applications. Besides, the performances of Li–S batteries at high current densities and sulfur loadings hold the key to bridge the gap between laboratory research and practical applications. To address the above issues and facilitate the practical utilization of Li–S batteries, the commercial separator is modified with solid electrolyte (nanorod LiAlO₂, LAO) and conductive carbon (Super P) to obtain a double coated separator (SPLAOMS). The SPLAOMS can physically barrier polysulfides and accelerate reaction kinetics. In addition, it enhances uniform lithium deposition, boosts ionic conductivity, and increases the utilization of active sulfur substances. The prepared Li–S batteries exhibit excellent cycling stability under harsh conditions (high sulfur loadings and high current densities) with an initial capacity of 733 mAh g⁻¹ and a capacity attenuation of 0.03% per cycle at 5C in 500 cycle life. Under ultra-high sulfur loading (8.2 mg cm⁻²), the prepared battery maintains a satisfactory capacity of 800 mAh g⁻¹ during cycling, demonstrating enormous commercial application potential. This study serves as a pivotal reference for the commercialization of high-performance Li–S batteries.