PEO-LiN(SO2CF2CF3)2 polymer electrolytes -: V.: Effect of fillers on ionic transport properties

Ionic transport properties, including ionic conductivity, lithium transference numbers, and diffusion coefficients, of poly(ethylene oxide)(20) LiN(SO2CF2CF3)(2)[P(EO)(20)LiBETI] and P(EO)(20)LiBETI + x (x = 2, 5 and 10) wt % filler (7 nm SiO2, 12 nm SiO2, and gamma-LiAlO2) polymer electrolytes prepared by a solvent-free procedure developed at ENEA have been investigated using ac impedance, dc polarization, and cyclic voltammetry. Regardless of whether or not nanosize fumed SiO2 particles were added, the ionic conductivity of all of the samples showed similar values and trends. Both the transference number and diffusion coefficient of lithium cations were decreased slightly by the addition of fumed SiO2 particles. These results suggest that the presence of nanosize fumed SiO2 particles in the P(EO)(20)LiBETI polymer electrolytes prepared under very dry conditions has little practical influence on the ionic transport properties. (C) 2004 The Electrochemical Society.