Catalyst Passivation and Coping Strategies in Lithium-Sulfur Batteries

Lithium-Sulfur battery (LSB) is promising to be one of the next-generation energy storage systems due to its exceptionally high energy density. Various catalysts are designed into the cathode to enhance the conversion efficiency of lithium polysulfides (LiPSs) and improve the comprehensive performance of LSB. Despite considerable attention devoted to discovering novel catalysts, catalyst passivation remains a frequently overlooked issue. This review summarizes recent findings on catalyst passivation mechanisms and coping strategies in LSBs. It also clarifies a common misconception in LSB catalyst design: that stronger catalyst-polysulfide interactions necessarily improve catalytic performance. A stronger interaction between these two components does not necessarily indicate superior catalytic performance and may actually lead to catalyst passivation. The catalyst passivation mechanisms are categorized into two types, based on the strength of the interaction between the catalyst and sulfur/sulfides. The first type involves a strong interaction, leading to physical coverage-induced reversible catalyst passivation. The second type is characterized by an ultra-strong interaction, resulting in chemical reaction-induced irreversible catalyst passivation. The coping strategies to guide the design of optimal catalyst for the cathode of LSB is also summarized. Finally, the future prospects and challenges of catalyst coping strategies in LSB are discussed.