Screening Non-Cationic Impurities for Short-Term Impacts on PEM Water Electrolysis

Water contamination remains an important challenge for the reliability and durability of polymer electrolyte membrane water electrolysis (PEMWE) and is a leading cause of stack failures. Recent research in the field has focused on understanding and mitigating cation contamination, but little is known about the impacts of non-cation contaminants in PEMWE. In this investigation, we screen a variety of non-cation impurities, including anions, weak acids, organics, and particulates, which may enter PEMWE cells from sources including system components, manufacturing residues, biological material, and inadequate purification. Impurity species are screened for short-term performance impacts and the reversibility of any observed impacts to determine if they should be considered detrimental contaminants. We find that anionic and weak acid impurities cause voltage impacts ranging from mild to insignificant that are generally reversible, except for chloride, which causes significant, irreversible degradation. Short-term impacts from acidic impurities at industrially relevant concentrations are generally negligible. The organic compounds considered cause voltage impacts ranging from moderate to insignificant, which are generally reversible. No voltage impacts are observed for the particulate material tested. These results can help inform PEMWE water purification and system management practices and guide future research on the topic.