Ultra Soft X-ray Absorption Spectroscopy and Photoelectron Spectroscopy Studies on Related Materials and Cathodes of Lithium Ion batteries

For analysis of lithium ion batteries, the ultra soft X-ray absorption spectroscopy beamline BL-2 at SR center of Ritsumeikan University has been improving: adding the new grating (900 l/mm) to the monochromator for higher energy up to 1000eV, and constructing the XAFS-PES (photoelectron spectroscopy) chamber equipped with in-situ transfer vessel systems. To elucidate the performance of this beamline, Li-K, O-K and TM-L XAFS and Li1s PES of related materials and cathodes have been measured. Finally, for precise analysis on the chemical state of Li, reference samples of Li compounds were also in-situ prepared by using deposition. Li K-XAFS spectra of deposited Li metal shows fine features compared with that of ground Li metal. A strong peak of Li1s photoelectron indicates that fresh surface layer of Li metal was prepared.