Journal of Power Sources, Vol.196, No.22, 9331-9338, 2011
High-temperature water-free proton conducting membranes based on poly(arylene ether ketone) containing pendant quaternary ammonium groups with enhanced proton transport
Poly(arylene ether ketone) containing pendant quaternary ammonium groups (QPAEKs) are anion-conducting polymers synthesized from benzylmethyl-containing poly(arylene ether ketone)s (PAEK-TM). Then QPAEK membranes doped with different concentrations of H(3)PO(4) are prepared and evaluated as high temperature proton exchange membranes. The H(3)PO(4) doping ability of quaternary ammonium groups in QPAEK system is found to be stronger than that of imidazole groups in polybenzimidazole system. The doping level of resulting QPAEK/H(3)PO(4) composite membranes increases with both the concentration level of soaking H(3)PO(4) solution and the ion exchange capacity. For example, the highest doping level of composite membranes is 28.6, which is derived from QPAEK-5 with an ion exchange capacity of 2.02 mmol g(-1) saturated with concentrated phosphoric acid. A strong correlation between the doping level and the proton conductivity is observed for all the membranes. Besides their low cost, novel high temperature proton exchange membranes, QPAEK/H(3)PO(4), show really high proton conductivity and possess excellent thermal and mechanical stability, suggesting a bright future for applications in high temperature fuel cell. (C) 2011 Elsevier B.V. All rights reserved.
Keywords:High temperature;Poly(arylene ether ketone);Phosphoric acid;Proton exchange membrane;Fuel cell