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Johnston, K. E., Sourati, M. T., Stieyano, L., Darwiche, A., Dupre, N., Grey, C. P. & Monconduit, L. (2016) Effects of Relaxation on Conversion Negative Electrode Materials for Li-lon Batteries: A Study of TiSnSb Using Sn-119 Mossbauer and Li-7 MAS NMR Spectroscopies. Chem. Mat. 28 4032–4041.
Added by: Richard Baschera (2016-07-11 09:25:06) Last edited by: Richard Baschera (2016-07-11 09:29:50) |
| Type de référence: Article DOI: 10.1021/acs.chemmater.6b01502 Numéro d'identification (ISBN etc.): 0897-4756 Clé BibTeX: Johnston2016 Voir tous les détails bibliographiques  |
Catégories: INTERNATIONAL, ST2E Mots-clés: Anode, cell, ion batteries, Lithium batteries, Operando, performance, reactivity, spectra Créateurs: Darwiche, Dupre, Grey, Johnston, Monconduit, Sourati, Stieyano Collection: Chem. Mat. |
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| Résumé |
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Conversion materials were recently considered as plausible alternatives to conventional insertion negative electrode materials in lithium-ion batteries due to their large gravimetric and volumetric energy densities. The ternary alloy TiSnSb was recently proposed as a suitable negative electrode material due to its large capacity (550 mA h g(-1)) and rate capability over many cycles. TiSnSb has been investigated at the end of lithiation (discharge) using Sn-119 Mossbauer and Li-7 magic-angle spinning (MAS) NMR spectroscopies to determine the species formed, their relative stabilities and their behavior during relaxation. During discharge, TiSnSb undergoes a conversion reaction to produce a mixture of phases believed to consist of lithium antimonides, lithium stannides, and titanium metal. In situ Sn-119 Mossbauer spectroscopy indicates the presence of Li7Sn2 at the end of discharge, while Li-7 NMR experiments suggest the formation of two distinct Sn-containing species (tentatively assigned to Li7Sn2 and Li7Sn3), in addition to two Sb-containing species (tentatively assigned as Li3Sb and a non-stoichiometric phase of Li2Sb, Li2-xSb). To gain insight into the relative stabilities of the species formed, experiments have been completed under open circuit voltage conditions. A new Sn-based species has been identified via Sn-119 Mossbauer spectroscopy at the end of relaxation. Similar changes are observed in the Li-7 NMR spectra obtained during relaxation. The species created at the end of discharge are extremely unstable and spontaneously evolve towards delithiated phases. Surprisingly, it is possible to resume electrochemical cycling after relaxation. It is likely that this behavior can be extended to this family of electrode materials that undergo the conversion reaction.
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