Nafion/PTFE and zirconium phosphate modified Nafion/PTFE composite membranes for direct methanol fuel cells

We prepared Nafion/PTFE (NF) and zirconium phosphate (ZrP) hybridized Nafion/PTFE composite membranes (NF-ZrP). NF-ZrP composite membranes were prepared via two processes. One is impregnating sub-mu m porous PTFE membrane directly in a Nafion/ZrOCl2 solution (NF-Zr-d). The other is impregnating sub-mu m porous PTFE membrane in a Nafion solution to prepare NF composite membrane, and then the NF membrane was impregnated in a ZrOCl2 aqueous solution via in situ precipitation method (NF-Zr-I). The ZrOCl2 inserted in NF composite membranes was then reacted with phosphoric acid to form ZrP and thus NF-ZrP-d and NF-ZrP-I composite membranes were obtained. The direct methanol fuel cell (DMFC) performances of membrane electrode assemblies prepared from Nafion-117, NF, NF-ZrP-d, and NF-ZrP-I composite membranes were investigated. The effects of introducing sub-mu m porous PTFE film and ZrP particles into Nafion membranes on the DMFC performance were investigated. The influence of ZrP hybridizing process into NF membranes (the process of preparing NF-ZrP-I is inserting ZrOCl2 into NF membranes after Nation is annealed and the process of preparing NF-ZrP-d is mixing ZrOCl2 into a Nafion solution before Nation is annealed) on the morphology of NF-ZrP composite membranes and thus on the DMFC performance was also discussed. (c) 2007 Elsevier B.V. All rights reserved.