S/N-doped carbon nanofibers affording Fe7S8 particles with superior sodium storage

• Published in: Journal of power sources 2020-03, Vol.451, p.227790, Article 227790
• Main Authors: Li, Xiu, Liu, Tao, Wang, Yun-Xiao, Chou, Shu-Lei, Xu, Xun, Cao, Anmin, Chen, Libao
• Format: Article
• Language: English
• Subjects: Anode; Carbon nanofibers; Fe7S8; N-co-doping; Sodium-ion batteries
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2020.227790

Iron sulfides draw much attention as electrode candidates for sodium-ion batteries (SIBs) due to the rich chemical stoichiometries and high capacity. However, they usually exhibit poor cycling performance due to the large volume change during sodiation/desodiation process. In this work, we embed Fe7S8 nanoparticles into sulfur, nitrogen-doped carbon (S/N–C) nanofibers through electrospinning/sulfurization processes. The heteroatom doped carbon matrixes could effectively protect the Fe7S8 from structural collapse, obtaining a stable cycling performance. Moreover, the conductive matrixes with 1D structure can facilitate the diffusion of electrons, leading to good rate capability. As results, the as-designed Fe7S8@S/N–C nanofibers present a discharge capacity of 347 m Ah g−1 after 150 cycles at 1 A g−1 and a high rate capacity of 220 m Ah g−1 at 5 A g−1 in virtue of unique structural characteristics. •The S/N-doped carbon nanofibers can enhance the conductivity of Fe7S8.•Fe7S8 nanoparticles are embedded into the doped carbon nanofibers.•The Fe7S8@S/N–C nanofibers present a capacity of 347 mA h g−1 after 150 cycles.