Necklace-Like Sn@C Fiber Self-Supporting Electrode for High-Performance Sodium-Ion Battery

Sodium-ion battery (SIB) is regarded as the next generation of large-scale energy storage systems, but it still faces problems such as low energy density, severe expansion/contraction of electrode volume, and poor cycle performance. Herein, necklace-like Sn-MOF@PAN fibers are prepared by the electrospinning method and then carbonized into Sn-C necklace paper as the binder-free cathode in an SIB. In each bead, Sn nanoparticles are wrapped by a porous carbon shell. The morphology and composition of the necklace-shaped Sn@C nanofibers are optimized by adjusting the ratio of Sn-MOF/PAN in the precursor. Sn@C with the optimal composition has a high specific capacity of 207 mAh g⁻¹ even at a high current density of 2 A g⁻¹ and maintains a specific capacity of 327 mAh g⁻¹ after 100 cycles at a current density of 100 mA g⁻¹. This research provides a high-performance flexible electrode for SIBs.