Improved electrochemical performance of α-Fe2O3 nanorods and nanotubes confined in carbon nanoshells

Abstract

Core-shell α-Fe2O3@C nanorods (FC1) and nanotubes (FC2) are synthesized via a hydrothermal method with further annealing. The structure, morphology and lithium storage performance are investigated by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, thermogravimetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The electrode based on the core-shell nanotubes (FC2) delivers the reversible capacity of 1350mAhg−1 cycled at 100mAg−1 after 50 cycles, 1186mAhg−1at 500mAg−1 after 100 cycles, and 765mAhg−1at 2Ag−1 after 300 cycles, much higher than those of pure α-Fe2O3 nanotubes and the core-shell nanorods (FC1). Electrochemical measurements show that the tubular morphology and the carbon shell play an important role in affecting both the cycle life and the rate capability of the electrodes. These insights will be of benefits in designing of other anode materials for lithium-ion batteries.