The concentration behavior of lithium triflate at the surface of polymer electrolyte materials

Surface tension measurements were made on tetraglyme-lithium triflate complexes of varying concentrations. The surface tensions of the liquid glymes were found to initially decrease with respect to the pure glyme. This was attributed to a surface excess concentration of the free triflate ion. These results prompted the investigation of poly(ethylene oxide)-lithium triflate films by the use of ATR FT-IR for the film surface and FT-IR transmission for bulk film studies. These data indicated that the free ion is the dominant species at the surface while ion pairs are more prevalent in the bulk.