Changes in Li4Ti5O12 (LTO) Structure due to Charge Effects Analyzed by Resonant Inelastic X-Ray Scattering in Combination with Multivariate Methods

JUAN JOSÉ LEANI; MATEUSZ CZYZYCKI; HÉCTOR JORGE SÁNCHEZ; JOSÉ ROBLEDO; ANDREAS GERMANOS KARYDAS; FABIANA OLIVA; ALESSANDRO MIGLIORI

Gotemburgo

Conferencia; European Conference on X-Ray Spectrometry (EXRS). 2016; 2016

University of Gothemburg

During the last two decades, the compound Li4Ti5O12 (also known as LTO) has been investigated as anode material of lithium ion batteries for several applications as energy storage for electric and hybrid vehicles due to its exceptional features [1-3]. This LTO compound has shown a remarkable Li-ion intercalation/de-intercalation reversibility, demonstrating also zero-strain volume change during the cycling process, with the addition of a notable safety performance. Furthermore, LTO has a high voltage plateau in comparison with other anode material candidates, helping to avoid the formation of metallic lithium [4]. Due to its performance and potential applications, a deep knowledge regarding the behavior of this LTO compound is of highly interest. A wide variety of techniques and tools have to be utilized in order to fulfill this need.In this work, Resonant Inelastic X-ray Scattering (RIXS) has been used, at a fixed energy of 4900 eV, for studying the titanium local environment changes in the LTO molecule when different levels of charge are applied. As complementary technique, XANES spectra across the Ti-K edge were also acquired in the energy range 4930-5080 eV. The measurements were carried out at the IAEA end-station of the XRF-beamline @Elettra Sincrotrone Trieste (Italy). Six (6) samples with different charges (not charged, partially charged and fully charged) were measured by both techniques. . In order to discriminate the changes on the titanium chemical state of the LTO molecule, Principal Component Analysis (PCA) was applied on both the RIXS and XANES spectra.The results clearly demonstrate that RIXS is a very sensitive tool, allowing the detection of slight changes in the chemical environment of the LTO compound due to the different levels of charge. It is concluded that sensitive chemical studies similar to the ones performed with X-ray absorption techniques (XANES, EXAFS) can be also accomplished with this novel RIXS technique, with the clear advantages of fast acquisition and overcoming the need of applying any energy scan during the survey.[1] E. Ferg, R.J. Gummow, A.d. Kock, and M.M. Thackeray, J. Electrochem. Soc., 141, L147 (1994).[2] T. Ohzuku, A. Ueda, and N. Yamamoto, J. Electrochem. Soc., 142, 1431 (1995).[3] L. Aldon, P. Kubiak, M. Womes, J.C. Jumas, J. Olivier-Fourcade, J.L. Tirado, J.J. Corredor, and C. Perez Vicente, Chem. Mater., 16, 5721 (2004). [4] J-Eui Hong, R-Gyeong Oh, and K-Sun Ryuz, J. Electrochem. Soc., 162 A1978 (2015).