In recent years, there has been a significant emphasis on enhancing lithium-ion batteries, transforming electric vehicles, stationary storage technologies, and portable electronics. Their lifespan, particularly in relation to capacity fade, is predominantly influenced by electrode degradation and the deactivation of active materials. Another critical aspect impacting battery lifespan and performance is the solid electrolyte interphase (SEI). However, selecting the right analytical technique to study lithium-ion battery degradation and SEI properties presents challenges due to the necessity for detailed structural and chemical composition information, including light elements like lithium, with high surface sensitivity.
In this investigation, we utilized a unique combination of a Scanning Electron Microscope equipped with a Focused Ion Beam (FIB-SEM) and a compact Time-of-Flight Secondary Ion Mass Spectrometer (ToF-SIMS) to explore the topographical and chemical composition of both non-cycled and cycled lithium-ion battery electrodes. Our objective was to identify degradation mechanisms, including parasitic chemical reactions. By integrating SEM observations with ToF-SIMS and other analytical techniques such as Energy Dispersive X-ray Spectroscopy (EDS) and Raman spectroscopy on the same FIB-SEM system, we achieved comprehensive 2D and/or 3D characterization of lithium-ion battery materials. This approach yields insights into degradation processes, SEI properties, and electrode composition, enhancing our understanding of battery behavior at an internal level.