Nanoscale Colocalized Electrochemical and Structural Mapping of Metal Dissolution Reaction

Understanding the structure-activity relationship in electrochemical metal dissolution reactions is fundamentally important, from designing higher density batteries to mitigating corrosions. The kinetics of metal dissolution reaction is highly dependent on surface structures, including grain boundaries and local defects. However, directly probing the electrochemical activity at these sites is difficult because the conventional bulk electrochemistry measures an averaged kinetics, obscuring the structure-activity correlation. Herein, we report the colocalized mapping of an electrochemical metal dissolution reaction using Ag as a model system. The local dissolution kinetics is voltammetrically mapped via scanning electrochemical cell microscopy (SECCM), which is correlated with local structures obtained via colocalized electron backscattering diffraction (EBSD). Individual pits of similar to 200 nm are formed, and their geometries suggest dissolution is fastest in the direction parallel to the {111} planes. Enhanced dissolution kinetics is observed at the high-angle grain boundaries but not at twin boundaries, which are attributed to the different binding energy of Ag atoms. Furthermore, the faster local dissolution correlates with the geometrically necessary dislocation density. The work demonstrates the importance of nanoscale local electrochemical mapping and colocalized microscopic measurement in obtaining the structure-activity relationship for electrochemical reactions at complex interfaces.

Automated summary

Understanding the structure-activity relationship in electrochemical metal dissolution reactions is crucial for designing higher density batteries and mitigating corrosions. The kinetics of metal dissolution is strongly influenced by surface structures, such as grain boundaries and defects. However, directly probing the electrochemical activity at these sites is challenging due to the limitation of conventional bulk electrochemistry. In this study, the colocalized mapping of an electrochemical metal dissolution reaction using Ag as a model system is reported. The local dissolution kinetics is measured using scanning electrochemical cell microscopy (SECCM) and correlated with the local structures obtained via colocalized electron backscattering diffraction (EBSD). The findings reveal the importance of nanoscale local electrochemical mapping and colocalized microscopic measurement in understanding the structure-activity relationship for electrochemical reactions at complex interfaces.