CONICET | Buscador de Institutos y Recursos Humanos

In the last few years, the Li4Ti5O12 compound (also known as LTO) has been studied as anode material of lithium ion batteries for applications as energy storage for electric and hybrid vehicles [1-3]. This LTO compound has shown exceptional features, as an extraordinary Li-ion intercalation/de-intercalation reversibility, zero-strain volume change during the cycling process and a distinguished safety performance. Additionally, LTO has a high voltage plateau in comparison with other anode material candidates, helping to avoid the formation of metallic lithium [4]. Due to both its performance and potential applications, a better knowledge of this LTO compound is of highly interest. In order to fulfill this need, different techniques and tools have to be used.In this work, Resonant Inelastic X-ray Scattering in Total Reflection conditions (TR-RIXS) has been used to perform a depth-profile study of the changes in the local environment of titanium in the LTO molecule when different charge treatments are applied.The measurements were carried out at the Brazilian Synchrotron Light Source (LNLS, Campinas) in the D09B beamline in total reflection geometry and using monochromatic photons of 4900 eV, just beneath the K absorption edge of titanium. A grazing incidence angle scan was performed as to study the chemical environment at four different depths of the sample. Eight samples with different charge treatments were studied.Principal Component Analysis (PCA) was used on RIXS spectra in order to discriminate the changes on the titanium chemical state of the LTO molecule at different depths.The results showed that RIXS is a very sensitive tool, allowing the detection of slight changes in the chemical environment of the LTO compound at different depths due to different charge procedures.