(Digital Presentation) Chemical Workflow of Characterizing Lithium-Ion Battery Electrodes: From SEM-Eds PCA and FIB Tof-SIMS Analysis to XPS

Abstract

Lithium-ion batteries (LIBs) have revolutionized energy storage technology, with cathode materials playing a pivotal role in their performance. Nickel Manganese Cobalt (NMC) cathodes are essential components, where the nickel (Ni) content profoundly influences battery capacity and cycle time. Traditional methods, such as SEM-EDS element mapping, have limitations in resolving distinct NMC phases. To address this, we employ Principal Component Analysis (PCA) phase mapping, unveiling intricate NMC phase distinctions.Furthermore, we investigate into the crucial aspect of lithium-ion distribution within the cathode using Focused Ion Beam Time-of-Flight Secondary Ion Mass Spectrometry (FIB ToF-SIMS). This technique, when integrated a compact SIMS detector with a DualBeam microscope, provides invaluable insights into lithiation and delithiation processes regarding to battery cycling. Our finding on an electrode revealing that discharged cathodes exhibit 7Li+ signal 3.5 times higher than charged cathodes. The SIMS lithium mapping results illustrated the trapped lithium ions in charged cathodes, as well as the uniform return of lithium ions to cathode oxide material upon discharge. Additionally, our results highlight the preservation of oxygen levels in cathode chemistry during charging and discharging, except for its involvement in lithium intercalation. We also address the challenges associated with windowless EDS detectors for lithium detection based on published literatures.Expanding our investigations, we present novel results of FIB-SIMS at cryogenic conditions, unveiling the distribution of lithium and sodium in an anode electrode. Moreover, we illuminate disparities in lithium detection between room temperature and cryogenic temperature acquisitions, providing insights into the behaviour of slow-charged graphite anodes.In this abstract, we extend our presentation to include X-ray Photoelectron Spectroscopy (XPS) for the detection of organic and inorganic matter in battery electrodes.In summary, our work combines SEM-EDS PCA and FIB ToF-SIMS and XPS techniques to provide a comprehensive understanding of lithium-ion battery cathode, anode materials, contributing to advancements in energy storage technology. Keywords: Lithium-ion battery, EDS PCA phase mapping, FIB-ToF-SIMS, XPS, SEM-FIBReference[1] Ali Eftekhari, Energy Storage Materials, Volume 7, April 2017, Pages 157-180.[2] Chengge Jiao, Lex Pillatsch, Johannes Mulders, David Wall, August 2019, Microscopy and Microanalysis 25(S2):876-877.[3] Mingwei Shang, Xi Chen, Junjie Niu, Cell Reports Physical Science 3, 100767, February 16, 2022 Figure 1