Two-dimensional MXenes for lithium-sulfur batteries

Rechargeable lithium-sulfur(Li-S)batteries have attracted significant research attention due to their high capacity and energy density.However,their commercial applications are still hindered by challenges such as the shuttle effect of soluble lithium sulfide species,the insulating nature of sulfur,and the fast capacity decay of the electrodes.Various efforts are devoted to address these problems through questing more conductive hosts with abundant polysulfide chemisorption sites,as well as modifying the separators to physically/chemically retard the polysulfides migration.Two dimensional transition metal carbides,carbonitrides and nitrides,so-called MXenes,are ideal for confining the polysulfides shuttling effects due to their high conductivity,layered structure as well as rich surface terminations.As such,MXenes have thus been widely studied in Li-S batteries,focusing on the conductive sulfur hosts,polysulfides interfaces,and separators.Therefore,in this review,we summarize the significant progresses regarding the design of multifunctional MXene-based Li-S batteries and discuss the solutions for improving electrochemical performances in detail.In addition,challenges and perspectives of MXenes for Li-S batteries are also outlined.