Scanning electrochemical cell microscopy: An ideal technique for isolating grain boundary electrochemistry?

Scanning electrochemical cell microscopy (SECCM) is a powerful technique for high-resolution electrochemical mapping and localised electroanalysis at the nanoscale, enabled by a mobile droplet cell. Building on recent advances in the study of single entities, crystalline materials, and individual grains of polycrystalline surfaces, this article focuses on the application of SECCM to the direct electrochemical analysis of grain boundaries on metallic electrodes. Emphasis is placed on the inherent complexity of grain boundary behaviour, the advantages of SECCM relative to conventional macroscopic electrochemical approaches, and recent methodological developments that enable increasingly rigorous interrogation of grain boundary electrochemistry.