Enhancing Sodium Ion Battery Performance by Strongly Binding Nanostructured Sb₂S₃ on Sulfur-Doped Graphene Sheets

Sodium ion batteries (SIBs) have been considered a promising alternative to lithium ion batteries for large-scale energy storage. However, their inferior electrochemical performances, especially cyclability, become the major challenge for further development of SIBs. Large volume change and sluggish diffusion kinetics are generally considered to be responsible for the fast capacity degradation. Here we report the strong chemical bonding of nanostructured Sb₂S₃ on sulfur-doped graphene sheets (Sb₂S₃/SGS) that enables a stable capacity retention of 83% for 900 cycles with high capacities and excellent rate performances. To the best of our knowledge, the cycling performance of the Sb₂S₃/SGS composite is superior to those reported for any other Sb-based materials for SIBs. Computational calculations demonstrate that sulfur-doped graphene (SGS) has a stronger affinity for Sb₂S₃ and the discharge products than pure graphene, resulting in a robust composite architecture for outstanding cycling stability. Our study shows a feasible and effective way to solve the long-term cycling stability issue for SIBs.