Influence of cutting processes, welding, and surface pretreatment on the metallic ion release of gas diffusion layer in PEM electrolysis systems

For the cathodic gas-diffusion layer (GDL) in proton exchange membrane water electrolysis (PEMWE), multiple layers of stretched metal could be an interesting solution. They combine good water and gas transport with low contact resistances and economic benefits. However, the corrosion behavior of the stainless steel used for GDLs (most common DIN 1.4404/AISI 316L) needs to be thoroughly investigated, as metal cations can harm the cell performance. Multiple manufacturing steps and cleaning of the stretched metal layers can impact its corrosion resistance. We herein investigated the impact of stretching, spot welding, and cutting of the gas diffusion layers, as well as the cleaning thereof in immersion tests, and analyzed the electrolyte via inductively coupled plasma mass spectrometry (ICP-MS). Surface analysis with X-ray photoelectron spectroscopy (XPS) complemented our investigations. Overall, ion release from stainless steel GDLs can be reduced by optimizing the manufacturing and cleaning steps, which can decrease Fenton reactivity and thus membrane degradation. Stainless steel cathode GDLs can improve the competitiveness of PEM water electrolysis cells without increasing the interfacial contact resistance (ICR). • Stretched metal gas-diffusion layer. • Metal ion release of GDL. • Impact of GDL manufacturing steps on metal release.