Investigation on the degradation of MEAs for PEM water electrolysers part I: Effects of testing conditions on MEA performances and membrane properties

Proton exchange membrane water electrolyzer (PEM WE) is an attractive electrochemical device that generates high purity hydrogen. However, its insufficient durability relatively to its high system cost is a bottleneck of that technology when compared to alkaline water electrolysis. In this work, the influence of the ageing protocols on PEM WE performances is investigated. From electrochemical and physico-chemical analyses it was found that high temperature degrades the membrane more than the current density does. High F− content from the perfluorosulfonic acid (PFSA) membrane degradation was found on the cathode side. Such a result supports the 2 e− oxygen reduction reaction mechanism that generates hydrogen peroxide which is known as detrimental compound for the PFSA membranes. The monitoring of the fluoride rate might be a suitable parameter to estimate the membrane thickness change. In our test conditions at 80 °C the membrane thinning rate was found to be 25 nm/h using SEM images which was twice the value found from fluoride measurements.