Analysis of Li Ion Battery Anodes Using In-situ FIB-ToF-SIMS

Depth profiling (1D or 3D) is often used to determine the depth distribution of species in a material.Depth profiling works well when the surface of a sample is smooth and when the depth(s) are in the nm to micron thickness range.For thicker layers, one can mount the material in epoxy and generate a cross section which can be imaged.Unfortunately, cutting and polishing often damages (or at least smears) fragile materials such Li ion batteries.Over the two past decades, Focused Ion Beam (FIB) has proven to be a viable approach to expose sub surface layers 10s of microns thick which is often analyzed by SEM or TEM in conjunction with EDS [1].Unfortunately, most EDS detectors are not able to detect light species such as Li and C (especially at the degraded vacuum which most SEM's operate under), and definitely can not detect H. ToF-SIMS not only detects all elements (and their isotopes), it also allows for the analysis of molecular fragments which is often critical for understanding the material.FIB/ToF-SIMS has been used to analyze other material systems [2,3].