Looking inside electrodes at the microscale with LIBS: Li distribution

The enhancement of Lithium-ion batteries (capacity, power, life span, etc.) poses a significant challenge in the pursuit of decarbonizing individual modes of transportation. The behavior and performance of these batteries vary primarily based on the nature of their electrode materials, with some still undergoing development. To gain a deeper understanding of the aging mechanisms that occur during battery operation, it is essential to assess the distribution of lithium within the electrodes with the highest possible spatial resolution. In this study, we showcase the application of micro-LIBS imaging as a multi-elemental characterization tool for investigating the aging mechanisms. By employing a high numerical aperture (0.42) microscope objective and a short wavelength laser (266 nm), we have developed a high lateral resolution micro-LIBS imaging experimental device approaching 2 μm. Performance evaluation was conducted on a certified aluminum sample with a high silicon content (⁓18 %). The utility of this new micro-LIBS instrumentation in studying Nickel Manganese Cobalt (NMC) batteries, revealing the formation of preferential sites for inactive lithium in negative electrodes, is also demonstrated.