Tri-additive PEGDA-based quasi-solid electrolyte for enhanced ion transport and interface stability in Li-O2 batteries

Despite their potential to enhance safety and design flexibility in next-generation lithium batteries, particularly lithium-oxygen (Li-O 2 ) systems, solid polymer electrolytes (SPEs) face persistent challenges of insufficient ionic conductivity and high interfacial resistance. To address these limitations, we developed a novel PEGDA-based quasi-solid-state electrolytes (QSEs) through in situ polymerization, strategically incorporating three functional additives: cellulose acetate (CA), N-methyl-2-pyrrolidone (NMP), and fluoroethylene carbonate (FEC). The electrolyte design leverages multiple synergistic mechanisms: hydrogen bonding between CA and NMP optimizes microstructural organization for efficient Li⁺ transport pathways; carbonyl groups in NMP coordinate with Li⁺ to facilitate LiTFSI dissociation, while oxygen-rich functional groups in CA provide supplementary Li⁺ coordination sites; FEC is introduced to further improve interfacial stability. This molecular engineering approach achieves an impressive room-temperature ionic conductivity of 8.54 × 10 −4 S cm −1 and a high lithium-ion transference number of 0.78. The QSE demonstrated excellent cycling stability (>900 h) in lithium symmetrical batteries and significantly improved the discharge capacity (12243 mAh g −1 ) and long-term cycling performance (590 h) of Li-O 2 batteries. These results highlight the efficacy of our multi-functional additive strategy in overcoming fundamental limitations in solid electrolytes, offering important insights for the rational design of high-performance energy storage systems.