Synthesis of flexible Fe3O4/C nanofibers with buffering volume expansion performance and their application in lithium-ion batteries

Freestanding binder-free electrodes, as a new generation of electrode material, can effectively improve the energy density of lithium-ion batteries (LIBs). In this paper, novel structured Fe 3 O 4 /C composite nanofibers are successful synthesized by a simple electrospinning method followed by a thermal treatment process. The composite nanofibers have the unique internal voids between Fe 3 O 4 nanoparticles and carbon matrix. The Fe 3 O 4 /C nanofibers film with good flexibility and excellent electrical conductivity can be directly used to fabricate half-cell without any current collector, binder and additional conductive agent. As anode material for LIBs, the Fe 3 O 4 /C composite nanofibers deliver high reversible capacity (762 mA h g −1 at 0.5 A g −1 after 300 cycles). The results show that the internal voids in flexible Fe 3 O 4 /C composite nanofibers effectively buffer volume expansion of Fe 3 O 4 in lithium ion intercalation/deintercalation process and avoid the fracture of the nanofibers, which retain the structural integrity and improve the cycling stability of electrode. Therefore, the design and synthesis strategy of flexible nanofibers film are prospective for applications in next-generation flexible LIBs.