The effect of BPSH post treatment on DMFC performance and properties

Abstract

Direct methanol fuel cells (DMFCs) are being investigated for applications ranging from milliwatt (cell phones) to kilowatt (APUs) size scales. A common pitfall for DMFCs has been the inability of the electrolyte, typically Nafion, to act as an effective methanol barrier. Methanol crossover adversely affects the cell by lowering the cell voltage due to a mixed potential at the cathode and lower fuel utilization. Improved DMFC performance was demonstrated with sulfonated poly(arylene ether sulfone) copolymer membranes (1). Another study has shown the dependence of polymer properties and morphology on the post treatment of such membranes (2). In agreement with measurements on free-standing films, the fuel cell characteristics of these membranes have been found to have a strong dependence on acidification treatment. Methanol permeability, proton conductivity, and electro-osmotic drag coefficient all were found to increase when the membranes were acidified under boiling conditions versus a low-temperature process.