• • AlF3 additive (5–10 wt%) in PEO–LiTFSI increases Li+ transference number from <0.2 to near-unity, enabling >3600 h stable cycling in symmetric Li|Li cells (vs. ~550 h for neat PEO), directly addressing dendrite-induced short-circuit failures.
• • Fluoride nanoparticles disrupt PEO crystallinity, raising ionic conductivity to ~10^-4 S/cm at 25°C in fully amorphous poly(1,3-dioxolane) with ceramic fillers, a 10–100x improvement over standard PEO, critical for room-temperature operation.
• • Lewis-acid sites preferentially bind TFSI− anions, promoting salt dissociation and increasing free Li+ concentration, which reduces concentration polarization and improves rate capability in high-energy density cells.
• • In-situ formation of LiF-rich interphase (wide band-gap, high modulus) suppresses parasitic reactions and dendrite growth, extending cycle life and Coulombic efficiency, as demonstrated by >3600 h stable cycling without short-circuit.