Self-standing Na-storage anode of Fe2O3 nanodots encapsulated in porous N-doped carbon nanofibers with ultra-high cyclic stability

• Published in: Nano research 2018-08, Vol.11 (8), p.4026-4037
• Main Authors: Liu, Yongchang, Wang, Fanfan, Fan, Li-Zhen
• Format: Article
• Language: English
• Subjects: Anodes; Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Carbon; Carbon cycle; Carbon fibers; Chemistry and Materials Science; Condensed Matter Physics; Electrochemical analysis; Electrochemistry; Electrode materials; Encapsulation; Iron oxides; Materials Science; Nanofibers; Nanoparticles; Nanotechnology; Rechargeable batteries; Research Article; Retention; Sodium; Sodium-ion batteries; Stability
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-018-1985-0

Ultrasmall γ-Fe 2 O 3 nanodots (∼ 3.4 nm) were homogeneously encapsulated in interlinked porous N-doped carbon nanofibers (labeled as Fe 2 O 3 @C) at a considerable loading (∼ 51 wt.%) via an electrospinning technique. Moreover, the size and content of Fe 2 O 3 could be controlled by adjusting the synthesis conditions. The obtained Fe 2 O 3 @C that functioned as a self-standing membrane was used directly as a binder- and current collector-free anode for sodium-ion batteries, displaying fascinating electrochemical performance in terms of the exceptional rate capability (529 mA·h·g –1 at 100 mA·g –1 compared with 215 mA·h·g –1 at 10,000 mA·g –1 ) and unprecedented cyclic stability (98.3% capacity retention over 1,000 cycles). Furthermore, the Na-ion full cell constructed with the Fe 2 O 3 @C anode and a P2-Na 2/3 Ni 1/3 Mn 2/3 O 2 cathode also exhibited notable durability with 97.2% capacity retention after 300 cycles. This outstanding performance is attributed to the distinctive three-dimensional network structure of the very-fine Fe 2 O 3 nanoparticles uniformly embedded in the interconnected porous N-doped carbon nanofibers that effectively facilitated electronic/ionic transport and prevented active materials pulverization/aggregation caused by volume change upon prolonged cycling. The simple and scalable preparation route, as well as the excellent electrochemical performance, endows the Fe 2 O 3 @C nanofibers with great prospects as high-rate and long-life Na-storage anode materials.