Thermal and transport properties of the polymer electrolyte based on poly(vinyl alcohol)-LiOH-H_2O

摘要

Alkaline solid electrolyte membranes, based on the poly(vinyl alcohol) (PVAL), lithium hydroxide (LiOH) and water with various salt concentrations have been synthesized. These systems have anhydri-dous ionic conductivity (σ) as high as 2,9 x 10~(-4) Scm~(-1) at room temperature and show a linear dependence of ln(σ) with 1/T below 80℃. The thermal analysis indicated three transformations in the blends: at 205, 150 and -125℃, associated with decompositions, melting point and glass transition of the polymer blends, respectively. The X-ray spectra for the samples at room temperature show a peak at about 2θ = 20° for all salt concentrations and whose intensity depends on the amorphous character of the system. The results are discussed in terms of the high mobility of the Li~+ ions in the amorphous phase of the complex.