Research status and prospect of separators for magnesium-sulfur batteries

Magnesium-sulfur(Mg-S)batteries have attracted wide research attention in recent years,and are considered as one of the major candidates to replace lithium-ion batteries due to the high theoretical energy density,low costs of active materials,and high safety.However,there are still significant challenges that need to be overcome before they can reach the large-scale practical applications.The key issue is the dissolution and shuttle effect of magnesium polysulfides(Mg-PSs),which leads to severe capacity degradation and shortens cycling life,greatly limiting the development of Mg-S batteries.In order to overcome these challenges,great efforts have been made in cathode materials,electrolytes,and separators.Herein,we review the investigations on suppressing the shuttle effect of Mg-PSs via the modification of separators,including schemes such as coating the functional materials that can hold Mg-PSs on the surface of polyolefin-based or glass fiber(GF)separators,forming gel polymer separators via cross-linking polymerization reactions,and developing gel polymer electrolytes coupled with GF separators.Furthermore,an outlook is proposed for the future design on separator exploitation to accelerate the development of Mg-S battery technology.