Anion trapping materials are presently of major interest as additives to polymer electrolytes. The paper describes the influence of triphenylborane on the physicochemical properties (conductivity, viscosity) of the PEODME-LiX electrolytes. The effect of such type of additive was discussed for various triphenylborane/LiX (X=I-, ClO4-, BF4-, CF3SO3-, (SO2CF3)(2)N-) molar ratios. A possible mechanism for anion-triphenylborane interactions is postulated on the basis of conductivity and FT-IR spectroscopy results. The present work is a beginning of the systematic studies on the effect of the Lewis acidity of an additive on the properties of composite polymeric electrolytes. (c) 2005 Elsevier Ltd. All rights reserved.