Superior Capacity Retention Sn-Ni-Fe-C Composite Anodes for Lithium-Ion Batteries

Sn-Ni-Fe-C composite anodes have been synthesized by a mechanochemical reaction of Sn with Ni-C and Fe-C composites and characterized. The Sn-Ni-Fe-C composite consisting of nanostructured Sn4Ni3, Sn2Fe, and SnFe along with carbon exhibits excellent capacity retention with a capacity of over 400 mAh/g. X-ray diffraction characterization of the electrodes reveals that while Sn2Fe decomposes completely during the lithiation process, both Sn4Ni3 and SnFe decompose only partially. The enhanced capacity retention of Sn-Ni-Fe-C compared to that of Sn is attributed to the buffering effect provided by Sn4Ni3 and SnFe and their effectiveness in suppressing the Sn grain growth during cycling.