Combined techniques gives nanoscale view of structural changes during electrochemical reactions

Probing nanoscale electrochemical processes and structural changes remains a challenge in spectroelectrochemistry, particularly pertaining to the interfacial reactions at solid-liquid interfaces. Scanning electrochemical cell microscopy (SECCM) can make highly localized electrochemical measurements, but by itself struggles with monitoring chemical structure changes incurred by electrochemical reactions.

Kumatani et al. developed a measurement system that combines the electrochemical probe of the SECCM system with Raman spectroscopy to obtain both localized electrochemical and spectroscopic data. The approach, called operando spectroscopy, assesses the meniscus formed on the surface of samples to characterize electrochemical reactions and the associated structural transformations while the reactions are taking place.

“The establishment of this newly developed operando measurement system represents a significant advance in solid-liquid interfacial studies involving electrochemical processes, including battery reactions, electrocatalytic reactions, corrosion science,” said author Akichika Kumatani. “It is expected to enable investigations unique to localized interfaces, such as single-entity electrochemistry, and to contribute to further developments in spectroelectrochemistry.”

The device uses the meniscus formed when a glass-pipette filled with electrolyte as a confined electrochemical cell contacts the sample surface. The Raman laser is aligned to the pipette’s tip.

The group demonstrated their approach by examining crystal flakes of lithium iron phosphate, a common material used in the cathodes of lithium-ion batters. The group was able to successfully monitor the lithium-ion charge-discharge processes during the reaction, allowing them to observe structural changes during lithium-ion intercalation.

They next look to push their operando measurements to capture time-dependent electrochemical changes arising from structural effects and elucidate interfacial processes within confined regions.

Source: “Raman-integrated scanning electrochemical cell microscopy for operando localized spectroelectrochemistry,” by Akichika Kumatani, Eita Tachizaki, Ryonosuke Ishige, Hiroki Ida, Yasufumi Takahashi, Susumu Shiraki, and Hitoshi Shiku, Applied Physics Letters (2026). The article can be accessed at https://doi.org/10.1063/5.0319771 .