The Electrochemical Sodiation of Sb Investigated by Operando X-ray Absorption and 121 Sb Mössbauer Spectroscopy: What Does One Really Learn?

Ali Darwiche (1) , Marcus Fehse (2, 3, 4) , Abdelfattah Mahmoud (5) , Camille Fontaine (6) , Bernard Fraisse (1) , Raphael P Hermann (7) , Marie-Liesse Doublet (1, 4, 8) , Laure Monconduit (1, 4, 8) , Moulay Tahar Sougrati (1, 4, 8) , Mouna Ben Yahia (1, 8) , Lorenzo Stievano (1, 4, 8)

1 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
2 ESRF - European Synchrotron Radiation Facility [Grenoble]
3 TU Delft - Delft University of Technology
4 ALISTORE-ERI - Advanced Lithium Energy Storage Systems - ALISTORE-ERI
5 GREENMAT - Group of Research in Energy and ENvironment from MATerials
6 SSOLEIL - Synchrotron SOLEIL
7 ORNL - Oak Ridge National Laboratory [Oak Ridge]
8 RS2E - Réseau sur le stockage électrochimique de l'énergie

In this study, we want to highlight the assets and restrictions of X-ray absorption spectroscopy (XAS) and Mössbauer spectroscopy for investigating the mechanism of the electrochemical reaction of antimony electrode materials vs. Na. For this, operando XAS was carried out during the first one and a half cycles, and the whole set of measured data was analysed using a statistical-chemometric approach, while low temperature Mössbauer spectroscopy measurements were carried out ex situ on selected samples stopped at different points of the electrochemical reaction. Complementary ab initio calculations were performed to support the experimental findings. Both techniques show that, upon the first sodiation, most Sb reacts with Na to form disordered Na 3 Sb. This step is accompanied by the formation of amorphous Sb as an intermediate. Upon inversion of the current Na 3 Sb is desodiated and an amorphous Sb phase, distinct from the pristine bulk Sb state, is gradually formed. However, both XAS and Mössbauer spectroscopy were unable to spot the formation of intermediate Na x Sb phases, which were evinced in previous works by operando Pair Distribution Function analyses. The results shown here clearly assign such failure to the intrinsic inability of both techniques to identify these intermediates.

Mots clés: X-ray absorption spectroscopy; Mössbauer spectroscopy; DFT calculations; chemometrics; MCR-ALS; Na-ion batteries; alloy reaction; Sb

Domaines: Matériaux

Ali Darwiche, Marcus Fehse, Abdelfattah Mahmoud, Camille Fontaine, Bernard Fraisse, et al.. The Electrochemical Sodiation of Sb Investigated by Operando X-ray Absorption and 121 Sb Mössbauer Spectroscopy: What Does One Really Learn?. Batteries, 2018, 4 (2), pp.25. ⟨10.3390/batteries4020025⟩. ⟨hal-01803348⟩