Ultrafine antimony (Sb) nanoparticles encapsulated into a carbon microfiber framework as an excellent LIB anode with a superlong life of more than 5000 cycles.

Antimony (Sb) anode has attracted increasing attention given its high theoretical capacity and suitable working potential. Nonetheless, its practical application is largely hindered by huge volume changes during the cyclic process, resulting in unsatisfactory long-term cycled stabilities at high current density. In this work, large-scale ultrafine Sb nanoparticles are functionally designed to encapsulate into a 3D carbon microfiber framework (CMF) via a scalable electrospinning approach followed by a thermal treatment process. This fabrication strategy effectively avoids the change in the volume of the Sb anode and provides a fast conductive network to serve as an efficient 3D e/Li transport pathway. Benefiting from this novel structural design, an ultrafine Sb nanoparticles@carbon microfiber framework (U-Sb-NPs@CMF) composite anode used for lithium-ion batteries (LIBs) delivers a high reversible capacity of 622 mAh g after 200 cycles at 0.5 A g and 507 mAh g after 2000 cycles at 2 Ag and a high-capacity retention of 350 mAh g even after 5000 long-term cycles. These outstanding charge-discharge performances suggest that the U-Sb-NPs@CMF composite is a promising candidate for an anode material in the application of LIBs.