Advanced core–shell hollow carbon nanofibers for ion and electron accessibility in sodium ion batteries

Abstract

One-dimensional core–shell hollow carbon nanofibers (HCNFs) have been synthesized by coaxial electrospinning, deacetylation and carbonization, which exhibit multi-surface properties that enhance electrolyte infiltration and facilitate ion/electron transport. The nitrogen-doped hard carbon outer shell compensates for the low conductivity of amorphous carbon, and the inner core carbon supports the stability of core–shell hollow structures. This unique structure ensures the accessibility of electrons/ions during electrochemical reactions and contributes to the superior rate performance of HCNFs. Ultimately, a high retention rate of 77% of the initial capacity value (0.1 A g⁻¹) was demonstrated at a current density of 2 A g⁻¹. The core–shell hollow structure designed in this work greatly optimizes the sodium transport dynamics.