Lift-Out Specimen Preparation and Multiscale Correlative Investigation of Li-Ion Battery Electrodes Using Focused Ion...

Advanced characterization is paramount to understanding battery cycling and degradation in greater detail. Herein, we present a novel methodology of battery electrode analysis, employing focused ion beam (FIB) secondary-ion mass spectrometry platforms coupled with a specific lift-out specimen preparation, allowing us to optimize analysis and prevent air contamination. Correlative microscopy, combining electron microscopy and chemical imaging of a liquid electrolyte Li-ion battery electrode, is performed over the entire electrode thickness down to subparticle domains. We observed a distinctive remnant lithiation among interparticles of the anode at the discharge state. Furthermore, chemical mapping reveals the nanometric architecture of advanced composite active materials with a lateral resolution of 16 nm and the presence of a solid electrolyte interface on the particle boundaries. We highlight the methodological advantages of studying interfaces and the ability to conduct high-performance chemical and morphological correlative analyses of battery materials and comment on their potential use in other fields.