Electrospun carbon nanofibers as anode materials for sodium ion batteries with excellent cycle performance

A simple and scalable electrospinning process followed by thermal treatment was used to fabricate carbon nanofibers (CFs). The as-prepared CFs were investigated as anode materials for sodium ion batteries (SIBs). Remarkably, due to their weakly ordered turbostratic structure and a large interlayer spacing between graphene sheets, the CFs exhibit a dominant adsorption/insertion sodium storage mechanism that shows high reversibility. As a result, the CFs show excellent electrochemical performance, especially cycle stability (97.7% capacity retention ratio over 200 cycles). Reversible capacities of 233 and 82 mA h g^-1 are obtained for the CFs at a current density of 0.05 A g^-1 and even a high current density of 2 A g^-1, respectively. The excellent cycle performance, high capacity and good rate capability make the CFs promising candidates for practical SIBs.