Exploration of the NaxMoO2 phase diagram for low sodium contents (x ≤ 0.5)

Laura Vitoux (1) , Marie Guignard (1) , Jacques Darriet (1) , Claude Delmas (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

The phase diagram of the layered NaxMoO2 system for low sodium contents (x ≤ 0.5) was explored using electrochemical (de)intercalation in a sodium ion battery from the Na2/3MoO2 composition which is the only one obtained by solid state reaction at high temperature. This study was realized using electrochemistry combined with in situ X-ray diffraction for sodium contents x below 0.5. For the first time, four single phase domains (x = 0.5, 0.4 ≤ x ≤ 0.42, x = 0.37, and x = 0.33) were evidenced during the cycling of the NaxMoO2 based battery in the 0.25 ≤ x ≤ 0.5 composition domain. All structural phase transitions are fully reversible. The existence of a superstructure was observed for the Na0.5MoO2 and Na0.33MoO2 compositions, attributed to the regular arrangements of both the sodium and molybdenum cations.

Domaines: Matériaux

Laura Vitoux, Marie Guignard, Jacques Darriet, Claude Delmas. Exploration of the NaxMoO2 phase diagram for low sodium contents (x ≤ 0.5). Journal of Materials Chemistry A, 2018, 6 (30), pp.14651-14662. ⟨10.1039/C8TA04224A⟩. ⟨hal-02127775⟩