Recent developments of micro-heaters based on micro-electromechanical systems (MEMS) for in situ experiments in the FIB-SEM chamber have enabled the use of TOF-SIMS for tracking chemical transport in high-temperature solid-state reactions. Additionally, the capability to prepare crosssectioned specimens, facilitated by the FIB, allows for in situ chemical mapping across interfaces at much higher spatial resolution compared to conventional microtome-based SIMS analysis (see Figure and Supporting Information, SI, for sample preparation details).