Probing Operating Electrochemical Interfaces by Photons and Neutrons

Abstract The operation of all electrochemical energy‐related systems, such as supercapacitors, batteries, fuel cells, etc. depends largely on the processes occurring at electrochemical interfaces at which charge separation and chemical reactions occur. Evolution of structure and composition at the interface between electrodes and electrolytes affects all the device′s functional parameters including power and long‐term performance stability. The analytical techniques capable of exploring the interfaces are still very limited, and more often only ex situ studies are performed. This sometimes leads to a loss of important pieces of the puzzle, hindering the development of novel technologies, as in many cases intermediates and electrochemical reaction products cannot be “quenched” for post‐process analyses. Techniques capable of operando probing of electrochemical interfaces by photons and neutrons have become an extensively growing field of research. This review aims at highlighting approaches and developing ideas on the adaptation of photoelectron, X‐ray absorption, vibrational spectroscopy, nuclear magnetic resonance, and X‐ray and neutron reflectometry in electrochemical studies.