Highly Stable Intermetallic FeSn₂-Graphite Composite Anode for Sodium-Ion Batteries

The development of anodes with high capacity, long cycle life and good rate capability is essential to expedite the commercialization of sodium-ion batteries for practical applications, including grid storage and electric vehicles (EV). Herein, we report the facile solvothermal synthesis of nanostructured iron distannide (FeSn₂) intermetallic particles as an alloy-type anode and the improvement of its cycle life by fabricating FeSn₂-graphite composites by a ball-milling process. The influence of graphite concentration on the sodium storage properties is studied. The composite anode delivered over 400 mAh g⁻¹ sodiation capacity over 200 cycles at a specific current of 100 mA g⁻¹. In addition, the composite anode exhibited excellent rate performance at higher current rates. This result would certainly pave the way for the development of high-performance anodes that would realize low-cost sodium-ion batteries with a longer calendar life.