Gel electrolyte via in situ polymerization to promote durable lithium-air batteries

Aprotic lithium-air batteries (LABs) have been known as the holy grail of energy storage systems due to their extremely high energy density. However, their real-world application is still hindered by the great challenges from the Li anode side, like dendrite growth and corrosion reactions, thus a pure oxygen atmosphere is usually adopted to prolong the lifetime of LABs, which is a major obstacle to fully liberate the energy density advantages of LABs. Here, a gel polymer electrolyte has been designed through in-situ polymerization of 1,3-dioxolane (DOL) by utilizing the unique semi-open nature of LABs to protect the Li anode to conquer its shortcomings, enabling the high-performance running of LABs in the ambient air. Unlike common liquid electrolytes, the in-situ formed gel polymer electrolyte could facilitate constructing a gradient SEI film with the gradual decrease of organic components from top to bottom, preventing the Li anode from dendrite growth and air-induced corrosion reactions and thus realizing durable Li repeated plating/stripping (2000 h). Benefiting from the anode protection effects of the gradient SEI film, the LABs display a long lifetime of 170 cycles, paving an avenue for practical, long-term, and high-efficiency operation of LABs.