Acid-base blend membranes based on 2-amino-benzimidazole and sulfonated poly(ether ether ketone) for direct methanol fuel cells

Direct methanol fuel cells (DMFC) are attractive for portable and automobile power needs, but their commercialization is hampered by high methanol permeability and the high cost of the currently used Nafion membrane. We report here a novel, low-cost blend membrane consisting of polysulfone-2-amide-benzimidazole (a basic polymer) and sulfonated poly(ether ether ketone) (an acidic polymer), which facilitates proton conduction through acid-base interactions while preserving excellent chemical and mechanical stabilities. The blend membrane exhibits performance in DMFC much higher than that of Nafion 115 and similar to that of Nalion 112, but with a remarkably superior long-term performance than Nafion 112 due to significantly reduced methanol crossover, enhancing the commercialization prospects of DMFC. (c) 2006 Elsevier B.V. All rights reserved.