High-throughput electrochemistry across length scales from macroscale screening to scanning electrochemical cell microscopy

High-throughput electrochemistry (HTE) has been dominated by macroscale platforms that achieve throughput through parallelisation, enabling efficient optimisation under system-relevant conditions. More recently, HTE concepts have extended toward micro- and nanoscale methodologies, where throughput arises from systematic exploration of electrochemical parameter space within a single experiment. In this context, scanning electrochemical cell microscopy (SECCM) has emerged as a versatile platform that combines serial, information-dense measurements with flexible experimental control, supporting both correlative structure-activity analysis and rapid optimisation of electrochemical conditions. The confined micro/nanoscale meniscus in SECCM gives rise to unique mass-transport characteristics, including fast diffusion, controlled ion migration, and access to gas|electrolyte|electrode three-phase boundaries that are not readily accessible at the macroscale. Tuneable probe sizes further enable direct linking of nanoscale behaviour to ensemble responses relevant to macroscale HTE, while dual-channel configurations allow local modulation of electrolyte composition without bulk solution exchange. This article reviews recent advances in macroscale HTE and SECCM-based micro/nanoscale screening, highlighting their complementary roles in scale-aware electrochemical optimisation.