η-Fe2O3 spindles as anode materials for lithium-ion batteries with excellent stable and high electrochemical performance

η-Fe2O3 composed of many sub-micrometer spindle-like particles has been successfully synthesized by a simple solvent-assisted precipitation route. The electrode of the as-obtained η-Fe2O3 powder shows a stable and ultrahigh reversible capacity of over 1200 mAh/g during up to 10 cycles at 100 mA/g and excellent rate capability, owing to the small and uniform grain size, mesoporous structure and advantageous crystallinity, which can be confirmed by SEM and TEM results. Based on the experimental results, it is believable that the η-Fe2O3 prepared by this method is a promising anode material for high energy-density lithium-ion batteries.

Graphical abstractThe high resolution HR-TEM image demonstrates a single η-Fe2O3 nanoparticle, showing high crystallinity. To our surprise, the clear edge, rarely seen in many similar reports, indicates its superior boundary crystallinity which favors rapid lithium ion transport.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We prepared η-Fe2O3 spindles by a simple solvent-assisted precipitation route. ► Electrode consists of small nanoparticles with a high degree of crystallinity. ► The initial discharge capacity reached unprecedented 1845.1 mAh/g at 100 mA/g. ► The reversible capacity retention was 788.8 mAh/g even at 800 mA/g.