Infrared nanoimaging and nanospectroscopy of electrochemical energy storage materials and interfaces

Electrochemical interfaces are central to the function and performance of energy storage devices. Thus, the development of new methods to characterize these interfaces, in conjunction with electrochemical performance, is essential for bridging the existing knowledge gaps and accelerating the development of energy storage technologies. Of particular need is the ability to characterize surfaces or interfaces in a non-destructive way with adequate resolution to discern individual structural and chemical building blocks. To this end, sub-diffraction-limit low-energy optical probes that exploit near-field interactions, such as pseudoheterodyne imaging, photothermal AFM-IR, and nanoscale Fourier transform infrared spectroscopy, are powerful emerging techniques. These are capable of surface probing and imaging at nanometer resolution. This review outlines recent efforts to characterize ex situ and in situ electrode materials and electrochemical interfaces in rechargeable batteries with infrared near-field probes.