DMSO/PEO-Based Gel Polymer Electrolyte for Li–O2 Batteries

Abstract

We investigate gel polymer electrolytes (GPEs) based on poly(ethylene oxide) (PEO) dissolved in dimethyl sulfoxide (DMSO) with LiTFSI for application in Li–O₂ batteries. A simple preparation route yields GPEs with tunable ionic conductivity controlled by the wt% of PEO. The resulting gels exhibit greater resistance to solvent oxidation compared to the analogous liquid electrolyte, while retaining the ability to promote oxygen-reduction pathways characteristic of conventional Li–O₂ systems. Li–O₂ cells incorporating these GPEs display outstanding cycling performance, achieving up to 4 times longer cycle life than cells employing liquid electrolytes and reaching 500 h of operation at 0.1 mA cm⁻² (26 mAh cm⁻²). Postmortem analysis revealed that the primary cause of capacity fade is the degradation of the GPE, particularly in regions adjacent to the lithium metal. These results highlight PEO-based GPEs as promising and easily processable electrolytes for improving the durability and safety of Li–O₂ batteries.