How to develop a homogeneous redox mediator (RM) towards both ORR and OER and how to prevent the shuttle effect are two main issues for Li-O₂ batteries thus far. Here, we firstly report 1,2-dimethyl-3-propylimidazolium iodide (DMPII), which serves multiple functions as a RM for discharge capacity promotion, a RM for charge potential reduction, and a Li anode protector for shuttling suppression by in situ generating a “self-defensed” SEI layer. Benefiting from these advantages, a cell with DMPII displays a stable cyclability with a low terminal charge potential of ∼ 3.6 V till the cell death, a considerable rate performance, and a good reversibility associated with Li₂O₂ formation and degradation. Based on the experimental and density functional theory (DFT) calculation results, a working mechanism for a cell operation is also proposed. These results represent a promising progress in the development of multiple-functional RM for Li-O₂ batteries. Moreover, we expect that this work gives an insight into the in situ protection of Li metal anode for board applications (e.g., Li-S batteries, all-solid-state Li-ion batteries, etc.).

迄今为止，如何为ORR和OER开发均匀的氧化还原介体（RM）以及如何防止穿梭效应是迄今为止Li-O ₂电池的两个主要问题。在这里，我们首先报告1,2-二甲基-3-丙基咪唑碘化物（DMPII），它具有多种功能，可用于提高放电容量的RM，用于降低电荷电势的RM和用于通过现场发电抑制穿梭的Li阳极保护器一个“自卫”的SEI层。得益于这些优点，具有DMPII的电池显示出稳定的可循环性，直至电池死亡前的终电荷电位低至约3.6 V，具有显着的速率性能以及与Li ₂ O ₂相关的良好可逆性形成和降解。基于实验和密度泛函理论（DFT）的计算结果，还提出了一种用于电池工作的工作机制。这些结果代表了用于Li-O ₂电池的多功能RM的发展中有希望的进展。此外，我们希望这项工作能够深入了解锂金属阳极在板子应用中的原位保护（例如， Li-S电池，全固态锂离子电池等）。