Depth-resolved Analysis of Titanium Chemical Environments in Li-ion Battery Electrodes by using GI-RRS Combined with Multivariate Methods

JOSE ROBLEDO; JUAN JOSÉ LEANI; F. OLIVA; A. KARYDAS; H.J. SÁNCHEZ; A. MIGLIORI

Trieste

Congreso; International Congress on X-ray Optics and Microanalysis (ICXOM24); 2017

Elettra Sincrotrone Trieste

Lithium-titanate compounds have been studied the last few decades as materials for lithium ion batteries which have applications as energy storage for mobile devices [1-3]. These compounds present several advantages in comparison with other anode material candidates [4]. Due to these features and potential applications, a better knowledge of how these materials store energy may have a direct impact in the technological industry.In this work, X-ray Resonant Raman Scattering in grazing incidence conditions (GI-RRS) has been applied to perform a depth-profile analysis of the titanium chemical state present in lithium-titanate compounds when different kind of charge treatments are applied.The measurements were carried out at the IAEA end-station of the XRF beamline @ Elettra Sincrotrone Trieste (Italy). The incident radiation energy was fixed just beneath the K-shell absorption edge of titanium. The incidence radiation angle was scanned with the aim of studying the local chemical environment of titanium at different probing depths. Several samples with different charge treatments were studied.Different Multivariate Methods were comparatively evaluated and used to process the RRS spectra with the aim to determine changes in the titanium local structure of the lithium-titanate compounds at different depths.The results showed that the RRS technique is a very versatile and sensitive tool, allowing the discrimination of small changes in the local chemical state of the lithium-titanate compounds due to the different charge procedures, thus allowing depth-resolved characterizations.