Composite polymer electrolytes were prepared consisting of amorphous polyether, Li salt and mesaporous inorganic filler, and we investigated their ion-conductive properties. We synthesized three types of filler, mesoporous silica, alumina and titania (MP-Si, Al, Ti), and characterized their structural and physicochemical properties using SEM, TEM, SAXS and BET surface area measurements. From these measurements, we confirmed that MP fillers have well-defined arrays of mesoporous and hexagonal structures. Dependence on the MP filler content of the glass transition temperature (T-g) revealed that the addition of filler to original polyether-salt electrolyte causes T-g decrease, to due to the dissociation of aggregated ions such as triples or crystalline complex domains. The MP-Ti composites had the greatest ionic conductivity (1.4 x 10(-5) S/cm, 7.5 wt% at 30 degrees C) of all samples, and the values were more than double that of the original. The addition of MP-Ti also increased the lithium transference number, because the electrolyte/filler interface provided active sites that increase mobile Li ions and conducting paths so as to enhance the mobility. (C) 2013 Elsevier Ltd. All rights reserved.