Antimony-based Intermetallic Alloy Anodes for High-Performance Sodium-Ion Batteries: Effect of Additives

Antimony (Sb)-containing intermetallic alloy compound consisting of molybdenum (Mo) and Sb dispersed in an amorphous carbon matrix was developed via high-energy mechanical milling and utilized as an anode for a sodium-ion battery. The structure and morphology of the as-prepared material were characterized using X-ray diffraction (XRD) and transmission electron microscope. Ex situXRD measurement confirmed the formation of a Na3Sb phase during sodiation. The electrochemical performance of the as-prepared Mo3Sb7-C composite demonstrated stable cyclability up to 40 cycles at a current rate of 100 mA/g. When a fluoroethylene carbonate additive was introduced into the electrolyte, the Mo3Sb7-C anodes exhibited a longer cyclic life with a capacity retention of similar to 90% at 100 cycles, as well as superior rate-cyclic performance corresponding to a capacity retention of more than 70% at 10000 mA/g. This enhanced electrochemical performance could be ascribed to the formation of a stable solid electrolyte interphase layer, smaller charge-transfer resistance, and better dispersion of Mo3Sb7 nanoparticles in the carbon matrix.