In situ techniques are a very powerful tool for investigating the evolution of physico-chemical phenomena, as they provide high veracity real-time information on the sequence of events and material transformations. Microscopic methods, in addition, allow probing phenomena at the meso and nanoscale, where the control over the operation of electrochemical devices happens: at the grain boundaries of a battery electrode material, in the conductive filaments of a memristor, in the space-charge layer of a gas sensor, etc. Applied to studies of lithium intercalation in vanadium pentoxide nanostructures, in situ scanning electron microscopy revealed details of lithiation, formation of SEI and electromigration mechanisms in single-nanowire battery devices. Furthermore, two novel scanning probe microscopy techniques and examples of their use for detecting local electrochemical activity in several ionically-active materials will be presented. The first order reversal curve current-voltage spectroscopy employs the coupling between the ionic motion and electronic conductivity to measure the former. The time-resolved Kelvin probe force microscopy method separates surface vs. bulk ionic activity on insulating surfaces in the time domain. Discussion of the benefits and future development of both techniques as well as the use of multivariate statistical methods for extracting physical meaning from the multidimensional datasets will close the presentation.
For further information please contact Nikolai Zhitenev, 301-975-6039, nikolai.zhitenev [at] nist.gov (nikolai[dot]zhitenev[at]nist[dot]gov)