Scanning electrochemical cell microscopy: High-resolution structure−property studies of mono- and polycrystalline electrode materials

Scanning electrochemical cell microscopy (SECCM) is a nanopipette-based scanning electrochemical probe microscopy technique that utilises a mobile droplet cell to measure and visualise electrode activity with high spatiotemporal resolution. This article spotlights the use of SECCM for studying the electrochemistry of crystalline electrode materials, ranging from well-defined monocrystals (e.g., transition metal dichalcogenides: MoS2, WS2 and WSe2) to structurally/compositionally heterogeneous polycrystals (e.g., polycrystalline Pt, Au, Pd, Cu, Zn, low carbon steel, boron-doped diamond) and covering the diverse areas of (photo)electrocatalysis, corrosion science, surface science and electroanalysis. In particular, it is emphasised how nanoscale-resolved information from SECCM is readily related to electrode structure and properties, collected at a commensurate scale with complementary, co-located microscopy/spectroscopy techniques, to allow structure–property relationships to be assigned directly and unambiguously.