A reversible long-life lithium–air battery in ambient air

Electrolyte degradation, Li dendrite formation and parasitic reactions with H2O and CO2 are all directly correlated to reversibility and cycleability of Li–air batteries when operated in ambient air. Here we replace easily decomposable liquid electrolytes with a solid Li-ion conductor, which acts as both a catholyte and a Li protector. Meanwhile, the conventional solid air cathodes are replaced with a gel cathode, which contacts directly with the solid catholyte to form a closed and sustainable gel/solid interface. The proposed Li–air cell has sustained repeated cycling in ambient air for 100 cycles (~78 days), with discharge capacity of 2,000 mAh g−1. The recharging is based largely on the reversible reactions of Li2CO3 product, originating from the initial discharge product of Li2O2 instead of electrolyte degradation. Our results demonstrate that a reversible long-life Li–air battery is attainable by coordinated approaches towards the focal issues of electrolytes and Li metal.