FeWO4Cl as cathode material for lithium rechargeable battery

Abstract

Lithium has been electrochemically and chemically intercalated into layered FeWO4Cl. The discharge curve between FeWO4Cl and Li 2FeWO4Cl is constituted by three potential plateaux and two domains where the cell voltage decreases rapidly upon the intercalation of lithium ions. A wide bi-phase domain is obtained for x in Li x FeWO4Cl ranging between 0.0 and 0.85. The limit of a solid solution extends in the vicinity of the LiFeWO4Cl composition. The theoretical and practical discharge capacities for Li1-xFeWO4Cl are 79.03 mAh/g and 78.45 mAh/g respectively. The structures of FeWO4Cl and LiFeWO4Cl were determined: from single crystal analysis and by Rietveld refinement of the powder X-ray diffraction pattern respectively. The modifications of the Fe-O bond lengths emphasize the iron reduction during the discharge process. Moreover, the strong change of Fe-Cl distance suggests a reversible framework modification. © 2008 Springer Science+Business Media, LLC.