Spatially-Resolved Electrochemical Methods for the Nanoscale Investigation of Reactivity and Transport in Materials for Energy Conversion and Storage

Electrochemistry plays a central role in developing technologies for energy storage and conversion such as batteries, fuel cells and photoelectrochemical systems. The analysis, quantification, and unraveling of several fundamental properties of these systems, many of which lack adequate in situ analytical methods, would impact positively our ability to understand, manipulate, and design better technologies. I will describe how reactive imaging techniques such as those based on Scanning ElectroChemical Microscopy (SECM) provide a unique approach to research in catalysis, batteries and novel materials such as graphene. Here, micro- and nano-electrode probes can be used to detect adsorbed species and to image their reactivity with spatial and temporal resolution on electrodes. SECM can use selective species that interrogate surface-bound molecules and reaction intermediates in electrocatalytic reactions, thus allowing us to obtain information about their surface dynamics. These studies follow those obtained in model electrode surfaces such as graphene, where the differential reactivity of chemically-formed species or selectively adsorbed redox-active complexes can be used to describe the impact of processing steps on this material and possibly to design new strategies in Electrocatalysis. Likewise, current efforts in our laboratory have explored the quantification and imaging at the Nanoscale of photoelectrogenerated species at strontium titanate anodes and their correlation to powerful in situ X-ray structural results from our collaborators.  Another front in our laboratory, consists in using ion-sensitive and selective strategies to provide a distinctive method of analysis for lithium-ion batteries, ion-selective membranes and ionic conductors. These methods allow assessing and tuning the impact of different chemical and electrochemical conditions on the ability of these materials to transfer ions. Efforts towards the imaging of these dynamic processes will be described.