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.