Journal of Power Sources, Vol.267, 203-211, 2014
LiF/Fe/V2O5 nanocomposite as high capacity cathode for lithium ion batteries
Iron fluoride based conversion cathode materials, LiF/Fe/V2O5 nanocomposites with high activity and good cyclic stability have been prepared in the discharged state by employing high energy ball milling and characterized by using XRD, SEM and TEM techniques. Li cycling behavior have been investigated by using galvanostatic cycling and cyclic voltammetry. It has been inferred that addition of V2O5 significantly enhanced the performance of the LiF/Fe nanocomposites by improving its electronic as well as its ionic conductivity. LiF/Fe/V2O5 (15 wt.%, 30 h ball milled) shows the best cycling performance. A high first cycle discharge capacity of similar to 510 (+/- 5) mA h g(-1) is observed. At the end of 50th cycle, the capacity observed is similar to 270 (+/- 5) mA h g-1. The heat treated LiF/Fe/V2O5 (15 wt.%, 20 h ball milled) nanocomposite shows a notable improvement in cycling stability than the as prepared nanocomposite and a reversible capacity of similar to 310 (+/- 5) mA h g(-1) is observed at the end of 50 cycles. The average charge discharge potentials observed in CV are similar to 2.9 and similar to 1.7 V, respectively. Ex-situ XRD, TEM and EIS measurements are performed on cycled electrodes of LiF/Fe/V2O5 (15 wt.%; 30 h ball milled) at selected voltages to understand the reaction mechanism. (C) 2014 Elsevier B.V. All rights reserved.
Keywords:Iron fluoride;Conversion materials;Nanocomposite;Electrochemical impedance spectroscopy;Lithium ion batteries