Introduction
Proton Exchange Membrane Water Electrolyzer (PEMWE) is currently considered as a promising solution for hydrogen production from renewable energy sources. However, its operational lifetime still falls short of the EU target under practical conditions. One of the key factors limiting durability improvement is the heterogeneity present in electrolyzers at various scales. Addressing the degradation caused by this heterogeneity is challenging because its complex impact mechanisms are not yet fully understood. This is largely due to the lack of appropriate characterization tools and test approaches that can provide sufficient and high-quality dataset allowing systematic study of the heterogeneity impact. Without quantification of the heterogeneity impact, the actual degradation prediction models could not fully adapt to the next-generation electrolyzers which tend to have large cell active areas and big cell numbers.
The proposed Multi-Hero project aims to clarify the impact of multiscale heterogeneity on the degradation of a key PEMWE component—the membrane electrode assembly (MEA)—by employing novel ex-situ and in-operando characterization tools across multiple scales, combined with tailored long-term degradation tests, and by enhancing degradation prediction models. To achieve this goal, we will adopt an interdisciplinary approach, drawing on the complementary expertise of two CNRS laboratories: one specializing in microscale ex-situ characterization, and the other in in-operando characterization at both the cell (small scale) and stack (macro scale) levels and degradation modeling.
We will begin by conducting microscale characterizations of a batch of commercial MEA components during the pre-assembly phase. Then, these characterized components will be used in in-operando accelerated stress tests at both the cell (small scale) and stack (macro scale) levels. The tests will be carried out over multiple experimental periods, with several test objects assessed during each cycle. After the degradation tests, post-mortem microscale analysis will be performed to investigate localized failure mechanisms. Each test cycle will incorporate novel characterization tools developed by the two partner teams—such as scanning gel electrochemical microscopy and zone-specific electrochemical impedance spectroscopy—to capture heterogeneity-related information at different spatial and structural scales. Finally, we will develop multiscale degradation models that integrate analytical data across the full PEMWE lifecycle—from “birth” to “death”—in order to quantify the impact of heterogeneity factors and their associated uncertainties, leveraging a batch testing approach.
The Multi-Hero project will empower PEMWE technology with cutting-edge multiscale characterization tools and modeling methods, enabling a deeper understanding of heterogeneity-driven degradation. Ultimately, the project’s outcomes will enhance the accuracy of degradation predictions under realistic operating conditions and provide insightful guidelines for optimizing the design and operation of PEMWEs.
Key words: membrane electrode assemble, degradation modelling, multiscale characterization, heterogeneity, proton exchange membrane water electrolyzer