Interlayer Material Selection for Lithium-Sulfur Batteries

Sulfur cathode offers a high theoretical specific capacity of 1,675 mAh g−1 and a high specific energy of 2,600 Wh kg−1 when implemented in lithium-sulfur batteries (LSBs). Moreover, sulfur is the redundant by-product of the petroleum industry, ensuring the low cost of LSBs. These features make LSBs particularly competitive among next-generation energy storage systems. However, the sulfur cathode suffers from several challenges such as a large volume change, low electrical conductivity of sulfur, as well as the polysulfide shuttle effect, which result in low utilization and loss of cathode active materials. Insertion of membranes (or so-called interlayers) between the separator and cathode has been demonstrated as a promising approach to alleviate these issues. In this review, recent progress regarding the advanced interlayer systems are summarized. Specifically, we generalize the different types of interlayers, and the operating mechanisms and widespread availability of interlayers in LSBs are concluded. Furthermore, the scientific/technical challenges and perspective are presented.