Poly(arylene ether) Ionomers with Pendant Quinuclidium Groups and Varying Molecular Weight for Alkaline Electrodes

The properties of the ionomer used to construct electrodes for direct methanol anionic fuel cells are critically important to the fuel cell performance. In this study, a new polymer backbone with a higher degree of fluorination for increased hydrophobicity has been shown to improve both the alkaline anode and cathode performance. It was also shown that decreasing the molecular weight of the ionomer improves fuel cell performance. Finally, higher fuel cell performance was observed with quinuclidinium head groups on the anionic ionomer, in comparison to the more traditional trimethyl ammonium cation. The improvements in performance appear to be due to improved mass transport of reactants and products through the electrode as a result of increased free volume within the electrode and a more efficient construction of the electrical double layer at the ionomer/catalyst interface.