Novel poly(vinyl alcohol)-KOH-H2O alkaline polymer electrolyte

A series of alkaline thin-film solid electrolytes, based on poly(vinyl alcohol) (PVA), potassium hydroxide (KOH) and water (PVA-KOH-H2O) were prepared. Their conductivity was studied using complex impedance method. The most conducting foils were composed of ca. 40 wt.% of PVA, 25-30 wt.% of KOH, and 30-35 wt.% of water. Typical conductivity of such foils reached the level of nearly 10(-3) Omega (-1) cm(-1) at room temperature. Temperature dependence of the conductivity was found to be in agreement with the Arrhenius expression with the activation energy of the order of 28-22 kJ mol(-1), depending on the electrolytes composition. The electrochemical stability window at the metal/electrolyte interface is of 1.5 V for stainless steel and nickel, and of 1.7 and 2.75 V for platinum and gold, respectively. Such alkaline electrolytes are interesting from the point of view of their potential application in all-solid rechargeable alkaline batteries as well as in small electrochemical devices, such as chemical capacitors, electrochromic or photogalvanic devices. (C) 2000 Elsevier Science B.V. All rights reserved.