| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1275055 | International Journal of Hydrogen Energy | 2012 | 9 Pages |
The influence of the membrane thickness on the performance and durability of 25 cm2 membrane electrode assembly (MEA) toward dynamic aging test was investigated. The tested MEAs consist of chemically stabilized membranes (AQUIVION™) with thicknesses of 30 and 50 μm, electrocatalyst – 46 %Pt/C (Tanaka) with Pt loadings of 0.25 (anode), 0.45 mg cm−2 (cathode) and gas diffusion layers 25 BC (SGL Group). The applied dynamic aging procedure is repetitive current cycling between 0.12 A cm−2 for 40 s and 0.6 A cm−2 for 20 s. The testing conditions were 80 °C, fully saturated hydrogen and air, total pressure of 2.5 atm abs. The aging procedure was regularly interrupted for evaluating the MEAs' “health” via electrochemical methods and mass spectrometry. The carbon support degradation as a function of the electrode potential, current cycling and supplied gas was studied. The effects of the Pt particles agglomeration and Pt physical loss in the active layer of the cathode on the MEAs performance degradation were individually assessed. The effect of the membrane thicknesses on the performance and durability of the PEFC was established. The reasons and stages of MEAs performance degradation were analyzed.
► Membrane thickness as a factor for PEFC performance and durability. ► Non-aged thin (30 μm) compared to thick (50 μm) PEM saves up to 35% of the MEA cost, while the durability is 2.5 times less. ► Shortly after aging start thick MEA performance surpasses the thin one. ► 95 % of the electrochemical surface area loss is caused by the Pt agglomeration. ► Carbon corrosion under steady state cell voltages (0.3 V – OCV) does not proceed in the absence of oxygen.
