A strong Lewis acid imparts high ionic conductivity and interfacial stability to polymer composite electrolytes towards all-solid-state Li-metal batteries

The development of high-performance solid polymer electrolytes is crucial for producing all-solid-state lithium metal batteries with high safety and energy density. However, the low ionic conductivity their unstable electrolyte/electrode interfaces have hindered widespread utilization. To address these critical challenges, a strong Lewis acid (aluminum fluoride (AlF3)) dual functionality introduced into polyethylene oxide) (PEO)-based electrolyte. AlF3 facilitates dissociation salt, increasing iontransfer efficiency due to acid-base interaction; further in-situ formation fluoride-rich interfacial layer promoted, which suppresses uneven deposition continuous undesired reactions between Li PEO matrix. Benefiting from our rational design, symmetric Li/Li battery modified electrolyte exhibits much longer cycling stability (over 3600 h) than that pure PEO/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) (550 h). Furthermore, LiFePO4 full cell composite displays higher Coulombic (98.4% after 150 cycles) without additive (63.3% at large voltage window 2.4–4.2 V, demonstrating improved interface batteries.