In this paper we report the combined, positive effect of triphenyloborane (BPh3) additive on conductivity and lithium cation transference numbers in poly(ethylene oxide) dimethyl ether (PEODME)-lithium trifluoromethanesulfonate(LiCF3SO3, LiTf electrolytes. The transport mechanism is discussed on the basis of impedance measurements, restricted diffusion t(+) measurements. ionic association semi-empirical quantitative estimation and spectroscopic studies. A substantial increase in the lithium transference number values in triphenylborane enriched composite electrolytes was observed in comparison with the pure PEODME-LiCF3SO3 electrolyte. This effect is assisted by ionic conductivity enhancement. (C) 2009 Published by Elsevier Ltd.