| Résumé | Hydroxyl anion conducting membranes have been developed using poly(vinyl alcohol) (PVA) as polymermatrix by incorporation of poly(diallyldimethylammonium chloride) (PDDA) as anion charge carriers. PDDA of four different molecular weight (namely PDDA-HMw, PDDA-MMw, PDDA-LMw and PDDA-ULMw) was incorporated in order to clarifying the effect of molecular weight on membrane performances. The membranes are characterized in detail by FTIR spectroscopy, scanning electron microscopy (SEM), thermal gravity analysis (TG), mechanical property, AC impedance technique, water uptake, swelling ratio, oxidation and alkaline stability to evaluate their applicability in alkaline fuel cells. The OH -conductivity of the membranes was found to be increased with increasing molecular weight of PDDA, and the maximum OH-conductivity of 0.027 S cm-1was achieved for PVA/PDDA-HMw membrane. ThePVA/PDDA-HMw membrane also showed the best mechanical property and excellent thermal stability due to the most compact and dense network structure. All the membranes showed relatively highoxidative stability in 30% H2O2and strong alkaline stability in 2 M KOH for 624 h at room temperature. The fuel cell performances of the MEAs with these membranes were 18.2, 23.4, 28.5 and 35.1 mW cm-2using H2and O2gases at 25°C. The long-term stability of single-cell performance showed that the PVA/PDDA membrane could approximately last 80 h on the fuel cell with only a slight decrease of 0.1 V in cell potential. © 2013 Elsevier Ltd. All rights reserved. |
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