Flexible, Flame-Resistant, and Dendrite-Impermeable Gel-Polymer Electrolyte for Li-O2 /Air Batteries Workable Under Hurdle Conditions.

Gel-polymer electrolytes are considered as a promising candidate for replacing the liquid electrolytes to address the safety concerns in Li-O2 /air batteries. In this work, by taking advantage of the hydrogen bond between thermoplastic polyurethane and aerogel SiO2 in gel polymer, a highly crosslinked quasi-solid electrolyte (FST-GPE) with multifeatures of high ionic conductivity, high mechanical flexibility, favorable flame resistance, and excellent Li dendrite impermeability is developed. The resulting gel-polymer Li-O2 /air batteries possess high reaction kinetics and stabilities due to the unique electrode-electrolyte interface and fast O2 diffusion in cathode, which can achieve up to 250 discharge-charge cycles (over 1000 h) in oxygen gas. Under ambient air atmosphere, excellent performances are observed for coin-type cells over 20 days and for prototype cells working under extreme bending conditions. Moreover, the FST-GPE electrolyte also exhibits durability to protect against fire, dendritic Li, and H2 O attack, demonstrating great potential for the design of practical Li-O2 /air batteries.