Synthesis and Properties of FeSn₂-C Composites as Anode Materials for Lithium-Ion Batteries

Abstract

Tin has a theoretical specific capacity as high as 990 mAh•g-1 , and is thus a potential anode material for high-energy-density lithium-ion batteries. However, it suffers from a huge volume change during lithiation/delithiation process, leading to poor cycle performance. In this paper, core/shell structured FeSn2-C composites were successfully synthesized by a simple high-energy ball milling technique with Sn, Fe, and graphite powder as raw materials. The FeSn2-C composite was evaluated as an anode material for lithium-ion batteries. The influence of milling time and final phase composition on the microstructure and electrochemical performance of FeSn2-C composites was systematically investigated. The failure mechanism of the FeSn2-C electrode was also analyzed. The results reveal that long milling time can promote the mechanical alloying process of the FeSn2 phase and reduce the particle size of the FeSn2-C composite, which are beneficial for the increase of the specific capacity and the improvement of the cycle performance of the FeSn2-C electrode. A high FeSn2 phase content leads to a high specific capacity of the FeSn2-C