Advancements in In Situ/Operando Characterization of Hydrogen Fuel Cells

Hydrogen fuel cells, as vital clean energy representatives, hold vast prospects in the energy domain. However, their actual processes involve numerous intricate physical and chemical reactions. To comprehend and optimize their functionality, various characterization techniques are employed to provide crucial insights into the electrochemical properties, structural composition, and reaction kinetics of fuel cells. This paper reviews the latest research advancements in in situ/operando characterization of hydrogen fuel cells, such as in situ/operando spectroscopic, electrochemical, and microscopy techniques. Initially, we briefly introduce the basic structure and principle of fuel cells, and the advantages and disadvantages of traditional characterization methods are outlined. Subsequently, the in situ Raman and infrared spectroscopy studies on the catalytic reaction mechanisms at the fuel cell interface are introduced. Then, using different in situ/operando characterizations, the water management, thermal management, membrane electrode degradation, and reaction process of fuel cells were monitored, obtaining information on morphology and species distribution. Finally, various characterization methods were summarized, and the future development of in situ/operando characterization techniques for fuel cells was discussed.