Identical-Location Electron Microscopy Applications for Electrode Materials in Electrochemical Energy Systems - Fuel...

As the world advances towards cleaner energy solutions, increased attention has been put towards researching electrochemical systems, such as fuel cells, electrolyzers, and batteries. However, before these technologies can be fully implemented, several key challenges must be addressed, among them nanoscale material degradation due to harsh working conditions. Understanding the degradation mechanisms holds the key to developing advanced materials and systems. Electron microscopy, particularly identical location electron microscopy (IL-EM), offers a detailed way to study and visualize these degradation processes. This technique enables the scrutiny of specific locations, down to the nano or atomic scale, both before and after subjecting materials to simulated operational conditions. It also provides valuable insights into morphological, chemical, and structural changes that occur following electrochemical tests. By combining electrochemical testing with electron microscopy, IL-EM has been advantageous for challenging old or formulating new hypotheses regarding materials degradation in a way that has been impossible with more traditional characterization approaches. This paper offers a comprehensive and up-to-date review of key aspects and findings related to the degradation of catalytic and electrode materials observed through IL-EM. It mainly focuses on IL transmission EM (IL-TEM) and applications to fuel cells due to the prevalence of published literature in this particular area; however, applications in electrolyzers and batteries, although limited, are also included in the review. In addition, less-utilized IL techniques such as scanning EM (IL-SEM) and electron tomography approaches are discussed as well. The versatility and efficiency of the IL technique are explored and discussed through a wealth of up-to-date, thought-provoking, and interrelated studies.