Laser-induced breakdown spectroscopy : A versatile tool for quality-controlled development of Li-based battery systems

Laser-induced breakdown spectroscopy (LIBS) is a relatively new diagnostic approach, which enables quantitative characterization of elemental composition, concentration and its distribution in lithium-ion based battery materials. A rather small research community is so far dealing with this topic, e.g., studying lithium composition in electrodes, analysis of binder distribution in composite thick films, or 3D imaging of solid-state electrolytes for lithium-ion batteries. At KIT, rapid analysis of large footprint electrodes was established for the first time regarding time-saving and controlled material screenings, and for recording of three-dimensional elemental profiles of entire electrodes. This analytic tool could also be easily implemented in battery manufacturing, even during continuous production. Anymore, the use of LIBS after battery operation provides additional information about cell cycling behavior, degradation mechanisms, and local lithium-ion insertion. It could be shown that LIBS is a powerful analysis tool for configuration of electrode designs, based on influencing factors such as porosity, thickness or laser-assisted surface modification. The latest has a strong impact on electrochemical performances, leading to a tremendous boost of lithium-ion mobility identified in fs-laser generated micro-pillars. This effect could be observed for modified composite cathode and anode materials which indicates that laser-structuring can fulfill the requirements for next generation batteries, providing both a contemporaneous high energy- and power density on battery-level. In this work a complete screening of electrodes, confirmed by quantitative measurements, will be presented. The LIBS technique is a versatile tool for battery materials development, in-line diagnostic tool, and post-mortem characterization for correlation with electrochemical data.