A Li–Air Battery with Ultralong Cycle Life in Ambient Air

The Li–air battery represents a promising power candidate for future electronics due to its extremely high energy density. However, the use of Li–air batteries is largely limited by their poor cyclability in ambient air. Herein, Li–air batteries with ultralong 610 cycles in ambient air are created by combination of low‐density polyethylene film that prevents water erosion and gel electrolyte that contains a redox mediator of LiI. The low‐density polyethylene film can restrain the side reactions of the discharge product of Li 2 O 2 to Li 2 CO 3 in ambient air, while the LiI can facilitate the electrochemical decomposition of Li 2 O 2 during charging, which improves the reversibility of the Li–air battery. All the components of the Li–air battery are flexible, which is particularly desirable for portable and wearable electronic devices.