This research project was focused on sodium layered oxides as cathode materials for Na-ion batteries. Actually, they present a lot of advantages, but they are not widely used because of their instability under atmosphere conditions. The stabilization of this material was the main objective of the topic. Two synthesis processes for NaNi0.5Mn0.5O2 have been compared. The classical method gave good results, but the new synthesis path under dry air showed a material with much more interesting properties in terms of cyclability and potential, even if the capacity still needed to be increased. The stability in ambient air of both samples was followed by X-ray diffraction. It has been found out the dry air synthesis allows to get an air-stable compound with no structural degradation. The electrochemical properties at high potential of the dry air sample were investigated, and it has been found out that at 4.2V, the participation of the oxygen redox reaction enabled to reach a capacity of 210 mAh/g. Nevertheless, after a few cycles, this phenomenon disappears and the capacity fades again to 95 mAh/g. The stabilization of this phenomenon has been investigated thanks to the collaboration with Umicore, by the introduction of Zinc within the material.
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