Mitigation of Polysulfide Shuttling by Interlayer/Permselective Separators in Lithium-Sulfur Batteries

A lithium-sulfur batteries system has been identified as a potential successor to lithium-ion batteries owing to its appealing properties such as extremely high theoretical specific capacity, energy density, low cost, and environmental benignancy. Despite these unique advantages, commercialization of this system is still hampered due to the inevitable shuttling of polysulfide between the electrodes which causes self-discharge and poor cycle life. This undesirable polysulfide shuttling can be mitigated by the introduction of a permselective/interlayer separator between the two electrodes. This contribution reviews state-of-the-art interlayer/permselective separators in view of their potential applications in lithium-sulfur batteries. This review mainly encompasses a brief description of the mechanism of inhibition of polysulfide shuttle by different types of interlayer/permselective materials coated on porous polyolefin membranes. The architecture and working principles of lithium-sulfur batteries are described. The characterization techniques which are used as a tool to analyze the membranes before and after cycling are discussed as well. The road ahead for Li-S batteries and the importance of permselective membranes in order to improve the electrochemical properties are emphasized.