Fabrication of Fe7S8/C flexible nanofibers with nano-buffered spaces and their application in Li-ion batteries†
Abstract
Much attention has been paid to freestanding and flexible electrodes of Li-ion batteries (LIBs) in order to match the requirements of the future trend of flexible electronics. In this paper, Fe7S8/C flexible nanofibers with nano-buffered spaces are synthesized by an electrospinning and vulcanization process. The Fe7S8/C flexible nanofiber film with enough flexibility and high electrical conductivity can be directly punched into a flexible electrode slice without current collector, binder and conductive additives. Experimental results show that the Fe7S8/CNF2-700 flexible nanofibers delivers a high reversible specific capacity of 675 mA h g−1 after 400 cycles at a current density of 1 A g−1. Its excellent electrochemical performance is mainly attributed to the fact that the carbon nanofiber affords a conductive pathway and the nano-void between the Fe7S8 nanoparticles and carbon matrix provides sufficient buffer space for the volume expansion of Fe7S8 during charge and discharge cycles. Therefore, it is quite hopeful that this composite nanofiber will become a potential candidate as an anode material for next-generation flexible LIBs.