Flexible Light-Weight Lithium-Ion-Conducting Inorganic–Organic Composite Electrolyte Membrane

A fast Li⁺-ion-conducting membrane is the key component behind successful performance of an aqueous or hybrid Li–air battery. Currently available ceramic ionic conductors are hardly scalable, difficult to seal, brittle, and electrochemically unstable against the commonly used catholytes. In this work, an easily scalable high-performance hybrid inorganic–organic membrane is realized that consists of NASICON-type Li_1+xAl_xGe_2–x(PO₄)₃ (LAGP) as the fast ion-conducting ceramic filler within a high-stability polymer blend. The as-prepared hybrid membrane exhibits high ionic conductivity of 1.0 × 10^–4 S cm^–1 with chemical stability in both neutral and acidified lithium chloride solutions. Energy efficiency of >93% under a current density of 0.03 mA cm^–2 for aqueous/hybrid Li–air batteries enabled by this hybrid anode-protecting membrane is demonstrated.