In-Depth Analysis of the Conversion Mechanism of TiSnSb vs Li by Operando Triple-Edge X-ray Absorption Spectroscopy: A Chemometric Approach

Fehse, M.; Darwiche, Ali; Sougrati, Moulay T.; Kelder, E.M.; Chadwick, Alan V.; Alfredsson, Maria; Monconduit, Laure; Stievano, Lorenzo

doi:10.1021/acs.chemmater.7b04088

In-Depth Analysis of the Conversion Mechanism of TiSnSb vs Li by Operando Triple-Edge X-ray Absorption Spectroscopy

Title

In-Depth Analysis of the Conversion Mechanism of TiSnSb vs Li by Operando Triple-Edge X-ray Absorption Spectroscopy: A Chemometric Approach

Author

Fehse, M. (TU Delft RST/Fundamental Aspects of Materials and Energy; European Synchrotron Radiation Facility; Universite de Picardie Jules Verne)
Darwiche, Ali (Université de Montpellier)
Sougrati, Moulay T. (Université de Montpellier; CNRS FR3459)
Kelder, E.M. (TU Delft RST/Fundamental Aspects of Materials and Energy; Universite de Picardie Jules Verne)
Chadwick, Alan V. (Universite de Picardie Jules Verne; University of Kent)
Alfredsson, Maria (Universite de Picardie Jules Verne; University of Kent)
Monconduit, Laure (Universite de Picardie Jules Verne; Université de Montpellier; CNRS FR3459)
Stievano, Lorenzo (Universite de Picardie Jules Verne; Université de Montpellier; CNRS FR3459)

Date

2017-12-26

Abstract

The electrochemical cycling mechanism of the ternary intermetallic TiSnSb, a promising conversion-type negative electrode material for lithium batteries, was thoroughly studied by operando X-ray absorption spectroscopy (XAS) at three different absorption edges, i.e., Ti, Sn, and Sb K-edge. Chemometric tools such as principal component analysis and multivariate curve resolution-alternating least squares were applied on the extensive data set to extract the maximum contained information in the whole set of operando data. The evolution of the near-edge (XANES) fingerprint and of the extended fine-structure (EXAFS) of the XAS spectra confirms the reversibility of the conversion mechanism, revealing that Ti forms metallic nanoparticles upon lithiation and binds back to both Sn and Sb upon the following delithiation. The formation of both Li₇Sn₂ and Li₃Sb upon lithiation was also clearly confirmed. The application of chemometric tools allowed the identification of a time shift between the reaction processes of Sn and Sb lithiation, indicating that the two metals do not react at the same time, in spite of a certain overlap between their respective reaction. Furthermore, XANES and EXAFS fingerprint show that the Ti-Sn-Sb species formed after one complete lithiation/delithiation cycle is distinct from the starting material TiSnSb.

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DOI

https://doi.org/10.1021/acs.chemmater.7b04088

Embargo date

2018-11-22

ISSN

0897-4756

Source

Chemistry of Materials, 29 (24), 10446-10454

Part of collection

Institutional Repository