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

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

Research output: Contribution to journalArticleScientificpeer-review

25 Citations (Scopus)
37 Downloads (Pure)

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.

Original languageEnglish
Pages (from-to)10446-10454
Number of pages9
JournalChemistry of Materials
Volume29
Issue number24
DOIs
Publication statusPublished - 26 Dec 2017

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