Transport properties of the solid polymer electrolyte system P(EO)nLiTFSI

Values for the lithium ion transference number (t(+)(0)) are reported for the solid polymer electrolyte system poly(ethylene oxide) (PEO) complexed with Li(CF3SO2)(2)N (LiTFSI). t(+)(0),ranges from 0.17 +/- 0.17 to 0.60 +/- 0.03 in the salt concentration (c) region of 742 to 2982 mol/m(3) at 85 degrees C. The concentration dependence of t(+)(0) and the molar ionic conductivity (Lambda) are shown to be in good agreement with a free volume approach over the salt-rich composition range investigated. The present t(+)(0) results were obtained using an electrochemical technique based on concentrated solution theory. This experimentally straightforward method is herein demonstrated to give accurate results for a highly concentrated SPE system, without relying on any dubious simplifications regarding the state of the electrolyte.