Ultra-stable Sb/hard carbon composite anodes with synergistic alkali-ion storage performances

Antimony based anode materials are attractive for alkali-ion battery applications due to their high theoretical capacity and lower insertion voltage. Herein, Sb/hard carbon composites are fabricated using a simple and scalable high-energy ball-milling approach and have been investigated as anodes for alkali-ion batteries. The structural and morphological studies reveal that Sb nanoparticles are embedded into hard carbon matrix, which provide mechanical buffer and conductive network to improve alkali-ion insertion kinetics. In sodium cells, the composite (HS5050) with optimized Sb loading delivers capacities of 250 mAh g(-1) at 100 mA g(-1) with excellent cycle life up to 800 cycles, compared to other composite and individual anodes. Remarkably, the same HS5050 provides higher capacities of 572 and 380 mAh g(-1) in lithium and potassium cells, respectively with impressive cycle life. The enhanced alkali-ion charge storage performances of composite anode are attributed to the synergistic effect of Sb and hard carbon.