Revisiting the Sodiation Mechanism of TiO 2 via Operando X-ray Absorption Spectroscopy

Marcus Fehse (1, 2) , Aurélien Henry (3) , Andrea Zitolo (4) , Bruno Boury (3) , Nicolas Louvain (3, 5) , Lorenzo Stievano (3, 5)

1 CIC ENERGIGUNE - Parque Tecnol Alava
2 ALISTORE-ERI - Advanced Lithium Energy Storage Systems - ALISTORE-ERI
3 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
4 SSOLEIL - Synchrotron SOLEIL
5 RS2E - Réseau sur le stockage électrochimique de l'énergie

The sodiation mechanism of TiO2 anatase was thoroughly investigated via X-ray absorption spectroscopy under operando conditions. The data set was analysed via an innovative and smart approach based on chemometric tools that allows the unbiased and reliable extraction of the maximum amount of meaningful information. The resulting data analysis reveals that the electrochemical sodiation mechanism is mainly based on the reduction of Ti4+ to Ti3+, going along with the irreversible amorphisation of the pristine anatase structure. At least one semi-amorphous intermediate is formed during the first discharge, whose local structure resembles those obtained at the end of the charge.

Mots clés: TiO 2; anatase; sodium-ion batteries; X-ray absorption spectroscopy; chemometrics

Domaines: Autre; Matériaux

Marcus Fehse, Aurélien Henry, Andrea Zitolo, Bruno Boury, Nicolas Louvain, et al.. Revisiting the Sodiation Mechanism of TiO 2 via Operando X-ray Absorption Spectroscopy. Applied Sciences, 2020, 10 (16), pp.5547. ⟨10.3390/app10165547⟩. ⟨hal-02914709⟩