화학공학소재연구정보센터
Journal of Power Sources, Vol.240, 359-367, 2013
Cross-linked poly(vinyl alcohol)/poly (diallyldimethylammonium chloride) as anion-exchange membrane for fuel cell applications
The novel, low-cost anion-exchange membranes (abbreviated as PVA/PDDA-OH-), made from poly(vinyl alcohol) and poly(diallyldimethylammonium chloride) blends, are successfully synthesized by a combined thermal and chemical cross-linking technique. The hydroxide (OH-) conductivity, water uptake, ion exchange capacity (IEC), thermal stability, oxidative stability and alkaline stability of PVA/PDDA-OH- membranes are measured to evaluate their applicability in alkaline fuel cells. The effects of cross-linking procedure, cross-linking time and membrane composition on OH- conductivity are studied using AC impedance technique. It is found that by cross-linking modifications, the membranes exhibit excellent thermal stability with onset degradation temperature high above 170 degrees C, a relatively high oxidative stability at 60 degrees C, and a strong alkaline stability in 8 M KOH at 80 degrees C. High OH- conductivity of 0.025 S cm(-1) is achieved at 25 degrees C and reaches up to 0.037 S cm(-1) at 80 degrees C. For exploring the conducting mechanisms, the concentration and mobility of charge carries of the membranes are also measured. The H-2/O-2 fuel cell tests with PVA/PDDA-OH- membranes yield the peak power density of 11.5 mW cm(-2) and greatly increase to 35.1 mW cm(-2) depending on PVA/PDDA mass ratio, on a low metal loading on both the anode and the cathode of 0.5 mg (Pt) cm(-2) at ambient temperature. (C) 2013 Elsevier B.V. All rights reserved.