Review of Separator Modification Strategies: Targeting Undesired Anion Transport in Room Temperature Sodium-Sulfur/Selenium/Iodine Batteries

Rechargeable sodium-sulfur/selenium/iodine (Na-S/Se/I2) batteries are regarded as promising candidates for large-scale energy storage systems, with the advantages of high energy density, low cost, and environmental friendliness. However, the electrochemical performances of Na-S/Se/I2 batteries are still restricted by several inherent issues, including the shuttle effect of polysulfides/polyselenides/polyiodides (PSs/PSes/PIs), sluggish kinetics of the conversion reactions at the cathodes, and Na dendrite growth at the anodes. Among these challenges, uncontrolled shuttle effect of PSs/PSes/PIs is a major contributing factor for the irreversible loss of active cathode materials and severe side reactions on Na metal anodes, leading to rapid failure of the batteries. Separator modification has been demonstrated to be an effective strategy to suppress the shuttling of PSs/PSes/PIs. Herein, the latest achievement in modifying separators for high-performance Na-S/Se/I2 batteries is comprehensively reviewed. The reaction mechanisms of each battery system are first discussed. Then, strategies of separator modification based on the different functions for regulating the transportation of PSs/PSes/PIs are summarized, including applying electrostatic repulsive interaction, introducing conductive layers, improving sieving effects, enhancing chemisorption capability, and adding efficient electrocatalysts. Finally, future perspectives on the practical application of modified separators in high-energy rechargeable batteries are provided. This review summarizes the most recent advances of modified separators in sodium-sulfur/selenium/iodine batteries. Separator modification strategies for regulating the shuttle effect of polysulfides/polyselenides/polyiodides are systematically discussed, including applying electrostatic repulsive interaction, improving sieving effects, enhancing chemisorption capability, introducing conductive layers, and adding efficient electrocatalysts.image

Automated summary

This review comprehensively discusses the latest advances in modifying separators for high-performance sodium-sulfur/selenium/iodine batteries. The article first discusses the reaction mechanisms of each battery system, and then summarizes different separator modification strategies for regulating the shuttle effect of polysulfides/polyselenides/polyiodides, including applying electrostatic repulsive interaction, introducing conductive layers, improving sieving effects, enhancing chemisorption capability, and adding efficient electrocatalysts. Future perspectives on the practical application of modified separators in high-energy rechargeable batteries are also provided.