Abstract
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 Na3Sb. This step is accompanied by the formation of amorphous Sb as an intermediate. Upon inversion of the current Na3Sb 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 NaxSb 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.
Original language | English |
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Article number | 25 |
Journal | Batteries |
Volume | 4 |
Issue number | 2 |
DOIs | |
State | Published - Jun 2018 |
Funding
Acknowledgments: S. Belin and V. Briois are gratefully acknowledged for their expert advice on beamline operation, Synchrotron Soleil (France) for providing beamtime at the beamline SAMBA. Alistore-European Research Institute is gratefully acknowledged for financial support through the postdoc grants to A.D. and M.F. Work by R.P.H. was sponsored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The research group Catalyse, Réactivité de Surface et Rayonnement Synchrotron (GDR CNRS 3590) is gratefully acknowledged for its information and supporting activity for the application of the chemometric approach in the analysis of spectroscopic data. S. Belin and V. Briois are gratefully acknowledged for their expert advice on beamline operation, Synchrotron Soleil (France) for providing beamtime at the beamline SAMBA. Alistore-European Research Institute is gratefully acknowledged for financial support through the postdoc grants to A.D. and M.F. Work by R.P.H. was sponsored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The research group Catalyse, Réactivité de Surface et Rayonnement Synchrotron (GDR CNRS 3590) is gratefully acknowledged for its information and supporting activity for the application of the chemometric approach in the analysis of spectroscopic data.
Funders | Funder number |
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UT-Battelle, LLC | |
U.S. Department of Energy |
Keywords
- Alloy reaction
- Chemometrics
- DFT calculations
- MCR-ALS
- Mössbauer spectroscopy
- Na-ion batteries
- Sb
- X-ray absorption spectroscopy