Title: Resolving Local Electrochemistry at the Nanoscale via Electrochemical Strain Microscopy: Modeling and Experiments,
Abstract: Electrochemistry is the underlying mechanism in a variety of energy
conversion and storage systems, and it is well known that the composition,
structure, and properties of electrochemical materials near active interfaces
often deviates substantially and inhomogeneously from the bulk properties. A
universal challenge facing the development of electrochemical systems is our
lack of understanding of physical and chemical rates at local length scales,
and the recently developed electrochemical strain microscopy (ESM) provides a
promising method to probe crucial local information regarding the underlying
electrochemical mechanisms. Here we develop a computational model that couples
mechanics and electrochemistry relevant for ESM experiments, with the goal to
enable quantitative analysis of electrochemical processes underneath a charged
scanning probe. We show that the model captures the essence of a number of
different ESM experiments, making it possible to de-convolute local ionic
concentration and diffusivity via combined ESM mapping, spectroscopy, and
relaxation studies. Through the combination of ESM experiments and
computations, it is thus possible to obtain deep insight into the local
electrochemistry at the nanoscale.