Details

Autor(en) / Beteiligte

• Zhang, Chengzhi
• Wei, Donghai
• Wang, Fei
• Zhang, Guanhua
• Duan, Junfei
• Han, Fei
• Duan, Huigao
• Liu, Jinshui

Titel

Highly active Fe7S8 encapsulated in N-doped hollow carbon nanofibers for high-rate sodium-ion batteries

Ist Teil von

• Journal of energy chemistry, 2021-02, Vol.53, p.26-35

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• NHCFs/Fe7S8 is rationally designed by combining high active Fe7S8 with high conductivity N-doped carbon. The robust structure with hollow carbon fibers and ultrathin carbon coating layer enables improved charge transfer kinetics and relieved volume expansion. [Display omitted] •The Fe/S atomic ratio in iron sulfides controls sodium-ion storage property.•Fe7S8 endows high electron conductivity, reaction reversibility and Na+ transport.•The structure with an ultrathin carbon coating layer to protect the Fe7S8.•The NHCFs/Fe7S8 as electrode shows high-rate capability in DME electrolyte. Nanostructured iron sulfides are regarded as a potential anode material for sodium-ion batteries in virtue of the rich natural abundance and remarkable theoretical capacity. However, poor rate performance and inferior cycling stability caused by sluggish kinetics and volume swelling represent two main obstacles at present. The previous research mainly focuses on nanostructure design and/or hybridizing with conductive materials. Further boosting the property by adjusting Fe/S atomic ratio in iron sulfides is rarely reported. In this work, Fe7S8 and FeS2 encapsulated in N-doped hollow carbon fibers (NHCFs/Fe7S8 and NHCFs/FeS2) are constructed by a combined chemical bath deposition and subsequent sulfidation treatment. The well-designed NHCFs/Fe7S8 electrode displays a remarkable capacity of 517 mAh g−1 at 2 A g−1 after 1000 cycles and a superb rate capability with a capability of 444 mAh g−1 even at 20 A g−1 in ether-based electrolyte. Additionally, the rate capability of NHCFs/Fe7S8 is superior to that of the contrast NHCFs/FeS2 electrode and also much better than the values of the most previously reported iron sulfide-based anodes. The in-depth mechanism explanation is explained by further experimental analysis and theoretical calculation, revealing Fe7S8 displays improved intrinsic electronic conductivity and faster Na+ diffusion coefficient as well as higher reaction reversibility.