A new desodiated derivative compound, Na0.89Fe1.8(SO4)3, was prepared by the chemical oxidation of alluaudite Na2.4Fe1.8(SO4)3 phase using NOBF4 as oxidant. The structure and valency of Fe were characterized by X-ray diffraction (XRD) and 57Fe Mössbauer spectroscopy. Intercalation behavior of lithium ions in the structure of Na0.89Fe1.8(SO4)3 was gauged by electrochemical analyses and ex-situ X-ray diffraction. A high capacity of 110 mAh g- 1 at 0.1 C was obtained with a good rate kinetics within a range of 0.1-10 C(1 C = 118 mAh g- 1) involving a high Fe3 +/Fe2 + redox potential of 3.75 V (vs. Li/Li+). These results confirmed that the Na2.4- δFe1.8(SO4)3 framework was stable even after oxidation and forms a new competitive cathode for the reversible intercalation of lithium ions.
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