In Situ/Operando Raman Techniques in Lithium-Sulfur Batteries

Tremendous efforts have been made to fulfill the promises of lithium-sulfur (Li-S) battery as the candidate for next-generation energy storage devices. However, challenges such as capacity degradation and dendrite growth still remain, hampering the commercialization of Li-S batteries. Different from the conventional ion-insertion-based lithium battery, the electrochemical and chemical processes in the cathode of Li-S battery are based on extremely complex conversion reactions. Together with the uncontrollable hostless lithium deposition process on the anode side, the future development of Li-S batteries faces great difficulty and requires deeper understanding of the fundamental mechanism. Herein, the recent applications of in situ/operando Raman techniques for monitoring the real-time variations in Li-S batteries are summarized to reveal the reaction mechanism and guide the design of strategies for improving the battery performances. The design concepts and advantages of in situ/operando Raman studies are highlighted, and the future explorations based on such technique are discussed, aiming to accelerate the development progress of Li-S battery for practical applications.