Nax(Fe,Mn)O2 Layered Oxides Used in Sodium Batteries : Structural Transformations Induced By the Electrochemical Process
In this context, we recently studied some NaxMO2 phases used as positive electrode in Na cells with a special focus on the structural transformations and redox processes occurring during cycling in P2- and O3-Nax(Fe,Mn)O2 systems. The structures of all starting materials were determined by Rietveld refinement from powder X-Ray diffraction data. The electrochemical study was carried out in sodium batteries with a solution of NaPF6 in PC as electrolyte. For all materials, a very good reversibility of the electrochemical process was observed. In situ and ex situ X-ray powder diffraction experiments were carried out to understand better the structural transformations induced by the electrochemical (de)intercalation process. In parallel, redox processes were studied by ex situ and in situ Mössbauer spectroscopy.
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