Towards understanding of component aging in dynamically operated polymer electrolyte water electrolyzers

摘要

If polymer electrolyte water electrolysis (PEWE) is to be deployed to serve as an energy storage technology in the grid, the potential challenges related to the component durability need to be understood and addressed. The PEWE industry has demonstrated several systems operating over 30,000 hours with degradation rates in the range of 0-5 μV/h [1,2]. Other systems with a lower content of precious metals in terms of protective coatings and catalysts show degradation rates ranging from 30-600 μV/h [3,4]. We focus on understanding correlations between component aging and cell performance deterioration. Owing to the complexity and coupling of degradation mechanisms, we develop methods to study individual mechanisms in suitable ex-situ experiments. In this study we investigate the effect of start-stop operation on the performance and gas purity of an in-house developed PEWE test-bench using commercially available Nafion 115 and Nafion 117 based catalyst coated membranes (CCMs). The cell was operated galvanostatically between 0 – 2 A/cm~2 at 60 oC for 100 hours. After 100 hours of testing, the degradation rates and hydrogen crossover for the two CCMs were evaluated at 1 A/cm~2. Additionally, we investigate whether the performance loss is reversible during the short cycling operation.