An analysis of degradation phenomena in polymer electrolyte membrane water electrolysis

• Published in: Journal of power sources 2016-09, Vol.326, p.120-128
• Main Authors: Rakousky, Christoph, Reimer, Uwe, Wippermann, Klaus, Carmo, Marcelo, Lueke, Wiebke, Stolten, Detlef
• Format: Article
• Language: English
• Subjects: Degradation; Durability; PEM electrolyzer; Porous transport layer; PTL; Water electrolysis
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2016.06.082

The durability of a polymer electrolyte membrane (PEM) water electrolysis single cell, assembled with regular porous transport layers (PTLs) is investigated for just over 1000 h. We observe a significant degradation rate of 194 μV h−1 and conclude that 78% of the detectable degradation can be explained by an increase in ohmic resistance, arising from the anodic Ti-PTL. Analysis of the polarization curves also indicates a decrease in the anodic exchange current density, j0, that results from the over-time contamination of the anode with Ti species. Furthermore, the average Pt-cathode particle size increases during the test, but we do not believe this phenomenon makes a significant contribution to increased cell voltages. To validate the anode Ti-PTL as a crucial source of increasing resistance, a second cell is assembled using Pt-coated Ti-PTLs. This yields a substantially reduced degradation rate of only 12 μV h−1, indicating that a non-corroding anode PTL is vital for PEM electrolyzers. It is our hope that forthcoming tailored PTLs will not only contribute to fast progress on cost-efficient stacks, but also to its long-term application of PEM electrolyzers involved in industrial processes. •Durability of state-of-the-art PEM electrolysis tested for just over 1000 h.•Reversible voltage increase recovers immediately after brief shut downs.•Titanium contamination of electrodes and observed growth of Pt particles.•Cell assembly highly affects results of CCM durability testing.•Pt-coated PTL reduces degradation by 89%.