Nanocrystalline Ag-Fe-Sn Anode Materials for Li-Ion Batteries

The Ag-Fe-Sn alloy powders prepared by mechanical alloying technique have been studied as anode material for lithium-ion batteries. The half-cell tests with lithium counter electrode revealed that a suitable substitution of Fe for Ag led to a significant improvement of the cycling performance of the electrodes. Among these electrodes, the Ag 36.4 Fe 15.6 Sn 48 electrode was found to be capable of keeping a rechargeable capacity of about 280 mAh/g over 300 cycles, which was better than that of the Fe-free Ag 52 Sn 48 electrode. Typically, the structural changes of the Ag 26 Fe 26 Sn 48 electrode during Li insertion and/or extraction were characterized using the combined techniques involving X-ray diffraction, high resolution transmission electron microscopy, selected area electron diffraction, and energy dispersive X-ray spectrometry. It is considered that the electrochemical properties of these electrodes are associated with their microstructure and morphology, such as the distribution of intermetallic compound Ag 3 Sn in Sn matrix, the Ag 3 Sn/Sn ratio as well as the presence of inactive Fe.