A flexible NASICON-type composite electrolyte for lithium-oxygen/air battery

Lithium-air/oxygen battery has raised widespread interest due to its extraordinary theoretical energy density (up to 3500 Wh kg −1 ). In this study, a flexible free-standing NASICON (Na-super ionic conductor)-type hybrid solid-state polymer electrolyte (HSPE) based on PVDF-HFP (poly(vinylidene fluoride-hexafluoropropylene)) copolymer and NASICON LATP (Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ) was prepared and investigated. The HSPE membranes exhibited an ionic conductivity of 1.02 × 10 −4  S cm −1 at room temperature along with a electrochemical window from 2 to 4.5 V. Using the HSPE, a lithium-oxygen/air battery with an inorganic solid-state cathode was fabricated. High initial discharge capacities of 4654 and 5564.3 mAh g −1 were reached under pure O 2 and ambient air, respectively. Compared to conventional porous polypropylene (PP) separator, the HSPE membrane alleviated the corrosion of the lithium anode, thus improving the cyclability of the cells. The results presented in this study suggest the great potential application of NASICON-type HSPE membrane in solid-state rechargeable lithium-air/oxygen batteries.