Typical approaches to studying solid-state reactions, including post-mortem measurements of reaction products by X-ray diffraction (XRD) or nuclear magnetic resonance (NMR) and computational modelling , can distinguish or identify the phases formed and their relative weights/fractions. However, average descriptions lack the resolution to visualize the spatial distributions of chemical elements and compounds. In turn, in situ heating experiments using transmission electron microscopy (TEM) combined with X-ray energy dispersive spectroscopy (EDS), diffraction, and energy filtered TEM (EFTEM) have been developed to map chemical and phase changes at the nanoscale . In addition to complexities in TEM due to highly constrained sample thicknesses and incompatibilities between EDS detectors and infrared radiation generated during heating, these electron microscopy techniques typically report only composition and morphological changes without chemical specificity on bonding or chemical environment changes in the solid state. Moreover, TEM and bulk diffraction-based techniques generally lack sensitivity to non-crystalline phases as well as minor, transient phases present during solid-state reactions. Time of flight secondary ion mass spectrometry (TOF-SIMS) at nanometer resolution, made possible by the use of a gallium (Ga) focused ion beam (FIB), provides an answer to these challenges by imaging the distribution of elements as well as their bonding encoded in multi-atom ions from the near-surface region of solids . TOF-SIMS uses an energetic primary ion beam to bombard the sample surface, resulting in the production of secondary ions and neutral species . The secondary ions are detected and separated based on their time-of-flight which is linearly linked to the square root of the mass per charge number (m/Q) ratio. Significantly, TOF-SIMS offers trace chemical detection, with detection limits reported in the parts-per-million to parts-per-billion range , as well as the capability to analyze and detect light elements with isotopic specificity. These advantages surpass the capabilities of TEM-EDS, albeit at lower spatial resolution, making TOF-SIMS a preferred choice for studying complex chemical processes in energy storage and hot corrosion .