Electrolytes for Rechargeable Lithium–Air Batteries

Lithium–air batteries are promising devices for electrochemical energy storage because of their ultrahigh energy density. However, it is still challenging to achieve practical Li–air batteries because of their severe capacity fading and poor rate capability. Electrolytes are the prime suspects for cell failure. In this Review, we focus on the opportunities and challenges of electrolytes for rechargeable Li–air batteries. A detailed summary of the reaction mechanisms, internal compositions, instability factors, selection criteria, and design ideas of the considered electrolytes is provided to obtain appropriate strategies to meet the battery requirements. In particular, ionic liquid (IL) electrolytes and solid‐state electrolytes show exciting opportunities to control both the high energy density and safety. Performance enhancers: Electrolytes for Li–air batteries include non‐aqueous liquid electrolytes, solid‐state electrolytes, aqueous electrolytes, and hybrid electrolytes. This Review shows the importance of electrolytes to the mechanisms and performance of lithium–air batteries and provides a basis for selecting suitable electrolytes. The existing challenges, solutions, as well as guidance for the future direction of this field are also considered.