Recent progress in polymer materials for advanced lithium-sulfur batteries

Abstract Polymers play essential roles in the research and development of rechargeable batteries, especially, lithium-sulfur (Li-S) batteries which have been considered as a promising candidate of the next-generation power supply mainly because of their high theoretical energy density (up to five-fold compared to state-of-the-art lithium-ion batteries). However, practical applications of Li-S batteries are mainly hindered by the insulating nature of sulfur and its intermediates, the polysulfide shuttle effect, and the formation and growth of lithium dendrites. Polymer materials play an important role in addressing these issues of Li-S batteries and their structures and functionalities can be manipulated to control the electrochemical performance of Li-S batteries (e.g., cylability, rate capability, lifespan, etc.). In this review, we concentrate on the recent development of various polymer materials for Li-S batteries. It starts with a brief introduction of the Li-S battery followed by its fundamental electrochemistry and challenges. Significant attention is then paid to the applications of various polymers in each component of Li-S batteries with a focus on the mechanisms behind their operation which are presented and further discussed from five perspectives: i) polymers in cathodes, ii) polymer electrolytes, iii) polymer interlayers, iv) polymer separators, and v) polymers for the lithium metal anode protection. The aim is to present a detailed review of the critical aspects related to the functional polymers that can be used as important resources for researchers working in a diverse range of fields dealing with Li-S batteries. Finally, conclusions and perspectives are presented.