Direct Local Mapping of Ion Transfer Reactions by Scanning Ohmic Microscopy

Abstract

AbstractScanning ohmic microscopy (SOM) detects a current by the potential difference along the current line. Using two microreference electrodes (MREs) and a very close distance to the electrode surface of interest, this principle can be used to record local current densities independently of the reaction that causes the current flow (ion or electron transfer processes). Ion transfer processes are difficult to image by scanning electrochemical microscopy (SECM). Here we present technical details of our SOM setup with possible extension required for the analysis of battery materials. In this respect, the selection of the specific voltage probes is explored for different applications. Our concept further uses voltage programs, for example, cyclic voltammetry, at each grid point of the image and the integration of specific voltage ranges to obtain material‐specific signals, and is extended by the use of a shear‐force detection unit at inclined capillaries for topographical imaging and an accurate vertical positioning of the probe.