Evaluation of the mechanical and chemical behavior of adhesives in KOH at elevated temperatures for alkaline water electrolysis

In the context of the ongoing discourse surrounding climate targets and carbon neutrality, hydrogen has garnered increased attention as a potential energy source. However, the cost of manufacturing electrolyzers continues to represent a significant obstacle to market entry. To lower these costs, adhesive bonding, as an automatable process, offers opportunities for cost reduction on the process side. However, to apply this technology, the adhesive must demonstrate resistance to the conditions within the electrolyzer. In this study, a range of commercially available one- and two-component epoxy resin adhesives are exposed to conditions of alkaline electrolysis (KOH, 90°C for 7 days). In order to gain insight into the behavior of the adhesives, a variety of analytical techniques were employed. To investigate the behavior of the adhesives under the given conditions, the change in sorption measurements, TGA, FTIR and Shore hardness was considered, taking into account the chemical composition. The adhesives demonstrated a high degree of variability. While the general structure of the resin made from bisphenol A or F appears stable, signs of degradation could be attributed to the hardener or other ingredients (plasticizers or adhesion promoters).