乙烯醇
热重分析
电解质
差示扫描量热法
材料科学
聚合物
电导率
氢氧化钾
介电谱
玻璃化转变
化学工程
化学
高分子化学
分析化学(期刊)
电化学
复合材料
有机化学
电极
物理化学
工程类
物理
热力学
作者
I. Palacios,Roberto Castillo,R.A. Vargas
标识
DOI:10.1016/s0013-4686(03)00204-4
摘要
In this work we report the preparation of a series of alkaline solid electrolyte membranes, based on poly(vinyl alcohol) (PVOH), potassium hydroxide (KOH) and water (PVOH–KOH–H2O). They were characterized by electrical conductivity measurements using impedance spectroscopy (EIS), by thermal measurements, using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The most conducting membranes were composed of 45% PVOH, 15% of KOH and 40% wt. of water whose conductivity reaches the value of 2.3×10−3 S cm−1 at room temperature. Temperature dependence of conductivity was found to follow an Arrhenius type behavior rather than the free volume type behavior associated with ion transport mechanism on polymer motion. The conducting phases are established between the observed glass transition of the blends at about 190 K up to where the water content in the sample is completely dehydrated, that is to say, 450 K. The effect of the humidity on the electrolytic characteristics of a cell M ∣ Polymer ∣ M (where M is stainless steel, silver) is quite remarkable. Changes in the conductivity of the polymer at room temperature between 1×10−5 and 2.3×10−3 S cm−1 when the relative humidity changes between the 25 and 85%, respectively, have been observed. The results are explained in terms of the plastification effects of water on the polymer and the presence of a (KOH/H2O) separated phase in the polymer. This new alkaline solid electrolyte is interesting from the point of view of its potential application as humidity sensor or electrolytic separator in alkaline batteries.
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