In Situ Reconstruction of Electrocatalysts for Lithium-Sulfur Batteries: Progress and Prospects

The current research of Li-S batteries primarily focuses on increasing the catalytic activity of electrocatalysts to inhibit the polysulfide shuttling and enhance the redox kinetics. However, the stability of electrocatalysts is largely neglected, given the premise that they are stable over extended cycles. Notably, the reconstruction of electrocatalysts during the electrochemical reaction process has recently been proposed. Such in situ reconstruction process inevitably leads to varied electrocatalytic behaviors, such as catalytic sites, selectivity, activity, and amounts of catalytic sites. Therefore, a crucial prerequisite for the design of highly effective electrocatalysts for Li-S batteries is an in-depth understanding of the variation of active sites and the influence factors for the in situ reconstruction behaviors, which has not achieved a fundamental understanding and summary. This review comprehensively summarizes the recent advances in understanding the reconstruction behaviors of different electrocatalysts for Li-S batteries during the electrochemical reaction process, mainly including metal nitrides, metal oxides, metal selenides, metal fluorides, metals/alloys, and metal sulfides. Moreover, the unexplored issues and major challenges of understanding the reconstruction chemistry are summarized and prospected. Based on this review, new perspectives are offered into the reconstruction and true active sites of electrocatalysts for Li-S batteries.