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 Ω−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.