Advanced Characterization Techniques in Promoting Mechanism Understanding for Lithium-Sulfur Batteries

Due to their numerous advantages, such as high specific capacity, lithium-sulfur batteries (Li-S batteries) have attracted much attention as next-generation energy storage systems. To meet future needs for commercial application, Li-S batteries will require both improved cycle life and high energy density. It is of critical importance to understand the fundamental mechanisms in Li-S systems to further improve the overall battery performance. Various advanced characterization techniques, over the past few years, have proven their important role in promoting the mechanism understanding for Li-S batteries. Here, the recent progress of mechanism understanding, including redox reactions, Li polysulfides dissolution, etc., in Li-S systems based on the advanced characterization techniques is reviewed. Special focus is placed on how these advanced characterization techniques are being employed and what characteristic or capability they possess. The importance of the combination of multiple characterization techniques, differences between ex situ and in situ experimental methods, as well as effects of characterization conditions in Li-S batteries are also discussed.