Electrochemical performance of LiMSnO (M = Fe, In) phases with ramsdellite structure as anodes for lithium batteries

LiMSnO4 (M = Fe, In) compounds were synthesized by high temperature solid-state reaction method and the electrochemical studies were carried out vs. lithium metal. Lithium is reversibly intercalated and deintercalated in LiFeSnO4 with a constant capacity of similar to90 mAh/g. In situ X-ray diffraction data show that ramsdellite structure is stable for lithium intercalation and deintercalation in LiFeSnO4. Galvanostatic discharge/charge of LiFeSnO4 in the voltage window 0.05-2.0 V shows a reversible capacity of similar to100 mAh/g. The observed capacity in LiFeSnO4 is due to the two processes involving alloying/dealloying of Li4.4Sn and formation/decomposition of Li2O. In contrast, the new isotypic oxide LiInSnO4 does not exhibit any lithium intercalation due to the absence of mixed valence for indium. Its reversible capacity is strongly dependent on the voltage window. LiInSnO4 exhibits severe capacity fading on cycling in the voltage window 0.05-2.OV, but shows a stable capacity of similar to90mAh/g in the voltage range 0.75-2.OV. (C) 2004 Elsevier Inc. All rights reserved.