Lithium Sulfur Batteries: Insights from Solvation Chemistry to Feasibility Designing Strategies for Practical Applications

Rechargeable lithium-sulfur (Li-S) batteries, featuring high energy density, low cost, and environmental friendliness, have been dubbed as one of the most promising candidates to replace current commercial rechargeable Li-ion batteries. However, their practical deployment has long been plagued by the infamous "shuttle effect" of soluble Li polysulfides (LiPSs) and the rampant growth of Li dendrites. Therefore, it is important to specifically elucidate the solvation structure in the Li-S system and systematically summarize the feasibility strategies that can simultaneously suppress the shuttle effect and the growth of Li dendrites for practical applications. This review attempts to achieve this goal. In this review, we first introduce the importance of developing Li-S batteries and highlight the key challenges. Then, we revisit the working principles of Li-S batteries and underscore the fundamental understanding of LiPSs. Next, we summarize some representative characterization techniques and theoretical calculations applied to characterize the solvation structure of LiPSs. Afterward, we overview feasible designing strategies that can simultaneously suppress the shuttle effect of soluble LiPSs and the growth of Li dendrites. Finally, we conclude and propose personal insights and perspectives on the future development of Li-S batteries. We envisage that this timely review can provide some inspiration to build better Li-S batteries for promoting practical applications. This review presents a systematic and comprehensive understanding on the solvation structure of Li polysulfides (LiPSs) in Li-S battery system, and summarizes some feasible designing strategies that can simultaneously suppress the shuttle effect of soluble LiPSs and the growth of Li dendrites, including designing host materials, modifying separators, and tailoring electrolytes, aiming to provide some inspirations to build better Li-S batteries for promoting the practical applications. image