High resolution electrochemical imaging methods provide opportunities to study localized phenomena on electrode surfaces. Here, we review recent advances in scanning electrochemical microscopy (SECM) to study materials involved in (electrocatalytic) energy-related applications. In particular, we discuss SECM as a powerful screening technique and also advances in novel techniques based on micro- and nanopipets, such as the scanning micropipet contact method and scanning electrochemical cell microscopy and their use in energy-related research.

Scanning tunneling microscopy (STM) has revolutionized the fields of heterogeneous catalysis and environmental sciences by providing unique insights into the atomic-scale structure of model catalysts. For the first time, STM has revealed the structure of active sites, including steps, kinks, and special atomic geometries in compounds. It has provided images of atomic scale dynamic processes, including diffusion and reactions. STM can operate in environments of gases and liquids, as found in real life and in industrial processes. We illustrate these unique capabilities with examples and how the information obtained can lead to industrially relevant information and help the design of new catalysts.

Atomistic and nanometer scale mechanisms of electrochemical reactions and ionic flows in solids in the nanometer–micron range persist as terra incognito in modern science. While structural and electronic phenomena are now accessible to electron and scanning probe microscopy (SPM) techniques, probing nanoscale electrochemistry requires the capability to probe local ionic currents. Here, we discuss principles and applications of electrochemical strain microscopy (ESM), a technique based on probing minute deformations induced by electric bias applied to an SPM tip. ESM imaging and spectroscopy are illustrated for several energy storage and conversion materials. We further argue that down-scaling of physical device structures based on oxides necessitates ionic and electrochemical effects to be taken into account. Future pathways for ESM development are discussed.

Atomic force microscopy (AFM)-based impedance spectroscopy provides localized impedance information of materials and interfaces at the nanoscale by utilizing the conductive AFM tip as a moving electrode to detect current response as a function of time and frequency under controlled environments. This capability enables AFM-based nanoscale impedance measurements to play a unique role in enhancing our understanding of many electronic and electrochemical devices. This article introduces the central concepts of AFM-based impedance measurement and reviews recent examples applying this technique to a variety of functional materials systems, in particular focusing on fuel cells, lithium-ion batteries, photoactive biomembranes, as well as other application examples.