High performance anode based on a partially fluorinated sulfonated polyether for direct methanol fuel cells operating at 130 C
Centre for Solar Energy and Hydrogen Research Baden-Wuerttemberg, Division 3, Electrochemical Energy Storage and Conversion, Helmholtzstr. 8, D-89081, Germany; Helmholtz Institute Ulm, Helmholtzstr. 8, D-89081 Ulm, Germany; Institute of Chemical Process Engineering, University of Stuttgart, Boeblingerstr. 72, D-70199 Stuttgart, Germany; North-West University, Chemical Resource Beneficiation, Potchefstroom, South Africa
Due to the disadvantages of the Nafion polymer for the application in the direct methanol fuel cell (DMFC) especial at temperatures above 100 C several polymers of the hydrocarbon type have already been investigated as membranes and ionomers in the DMFC. Among them were nonfluorinated and partially fluorinated arylene main-chain hydrocarbon polymers. In previous work, sulfonated polysulfone (sPSU) has been applied as the proton-conductive binder in the anode of a DMFC, ending up in good and stable performance. In continuation of this work, in the study presented here a polymer was prepared by polycondensation of decafluorobiphenyl and bisphenol AF. The formed polymer was sulfonated after polycondensation by oleum and the obtained partially fluorinated sulfonated polyether (SFS) was used as the binder and proton conductor in a DMFC anode operating at a temperature of 130 C. The SFS based anode with 5% as ionomer showed comparable performance for the methanol oxidation to Nafion based anodes and significant reduced performance degradation versus Nafion and sPSU based anodes on the Nafion 115 membrane. Membrane electrode assemblies (MEAs) with the SFS based anode showed drastically improved performance compared to MEAs with Nafion based anodes during operation with lower air pressure at the cathode. © 2014 Elsevier B.V. All rights reserved.
Catalyst layers; High-performance anodes; Medium temperature; Membrane electrode assemblies; Partially fluorinated; Performance degradation; Sulfonated polyether; Sulfonated polysulfone; Anodes; Atmospheric pressure; Binders; Ethers; Ionomers; Polycondensation; Polymers; Direct methanol fuel cells (DMFC)