Article
Mosaic Mapping for Analysis of Heterogeneous Battery Degradation
Surface Analysis Spotlight: XPS
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Batteries are complex systems with many materials and dynamic changes that occur during device operation. Understanding the chemistry of the interfacial (degradation-induced) layers is critical to understand how to design next-generation battery materials for improved stability and long-term performance. In order to determine representative composition and compare samples accurately for such heterogeneous materials, it is necessary to have both small-area analysis capabilities along with the ability to analyze large sample areas.
SmartMosaic® on PHI XPS instruments allows data to be collected efficiently at many sample positions with a Mosaic generated automatically at the end of the acquisition (Figure 1). X-ray induced scanning electron image (SXI) Mosaics allow quick visual inspection of heterogeneities and Spectral Mosaics provide chemical information that is representative of a larger sample piece. These unique capabilities are well-suited to studying heterogeneous samples with beam-sensitive chemistry, allowing batteries to be analyzed appropriately and compared with confidence.
Figure 1: Schematic of the Mosaic data setup and acquisition process.
In this application note, cathode-electrolyte interfaces were studied with and without a protective surface coating. SXI Mosaics showed morphological features such as cracks and pockmarks while Spectral Mosaics highlighted elemental and chemical-state distribution. Both images and spectra showed that the uncoated sample was extremely heterogeneous after cycling, with degradation species scattered across the interface, while the coated sample was effectively protected from harmful side reactions.
To learn more about unique features of PHI XPS and how they can elucidate important battery properties, please attend the upcoming talk “Surface Analysis of Engineered Particles for Improved Battery and Stability” by Dr. Jennifer Mann at AVS 70 in Tampa, FL this November.