FeSn2and CoSn2Electrode Materials for Na-Ion Batteries

Alloys have the potential to fill the void for a reliable, high-performing anode material for sodium ion batteries. Here we investigate for the first time CoSn 2 and FeSn 2 and their reaction with sodium. These tin alloys can achieve capacities of up to 680 mAh/g if fully exploited, almost double of the standard anode material used today. We elucidate the reaction mechanism of these two isostructural alloys by analogy to the well understood Sn-Na system, and demonstrate that the transition metal believed to be inactive by the community in fact strongly influences the reaction mechanism.