Raman-integrated scanning electrochemical cell microscopy for <i>operando</i> localized spectroelectrochemistry

Scanning electrochemical cell microscopy (SECCM) utilizes a meniscus formed between the sample surface and the tip of a glass pipette filled with electrolyte as a confined electrochemical cell, enabling highly localized electrochemical measurement. However, SECCM alone makes it challenging to monitor chemical structure changes that accompany electrochemical reactions. In this study, we developed an in operando measurement system that integrates Raman spectroscopy with an electrochemical probe of the SECCM system, allowing simultaneous acquisition of localized electrochemical and spectroscopic data. A single crystal flakes of LiFePO4, a cathode material for lithium-ion batteries, was prepared, and changes in Raman scattering during lithium-ion charge/discharge processes were successfully monitored through the meniscus formed on their surfaces. This combined system provides nanoscale insights into electrochemical reactions and the associated structural transformations.