An electrochemical cell for in operando small angle X-ray scattering and X-ray absorption spectroscopy analyses for proton exchange membrane fuel cells and electrolyzers

The effectiveness of the transition from fossil fuels-based energy systems, to (more) sustainable ones, can be strongly supported by establishing hydrogen-based economies in the so called hard-to-abate sectors (as for example heavy industry or maritime), where green hydrogen, produced via water electrolysis powered by renewable energy sources, is further processed by means of fuel cells to produce electrical energy. Producing efficient and cost-effective fuel cell systems and water electrolyzers is then fundamental for promoting the spread of green hydrogen generation and use. In this scenario, fuel cell technology remarkably improved in the last decades, promoting Proton Exchange Membrane Fuel Cells (PEMFCs) use in the automotive and in transportation sectors. Nonetheless, the complex architecture of fuel cells and electrolyzers, still slows down the research and development required for improving their efficiency and lifetime, and contemporary reducing their production costs, which are still strongly bounded to the cost of catalyst materials (Wang et al., 2020). Important achievements in optimizing fuel cell architecture and/or catalyst loading, were obtained thanks to analysis carried out in operando conditions, which allowed to increase the depth of knowledge about catalyst degradation phenomena (Shan et al., 2016). Moreover, important phenomena characterizing fuel cell operation and degradation were revealed by in operando analysis carried out at synchrotron facilities, or using neutrons as a probe. In particular, Small Angle X-ray Scattering (SAXS) was used for highlighting catalyst morphological evolution (Martens et al., 2022; Povia et al., 2018) (also supported by former studies on catalyst model systems (Bogar et al., 2021; Ruge et al., 2017)), while X-Ray Absorption Spectroscopy (XAS)