Facile Synthesis of Multi-Channel Surface-Modified Amorphous Iron Oxide Nanospheres as High-Performance Anode Materials for Lithium-Ion Batteries

Based on the synergistic effect of ripening and hydrogen ion etching in a hydrothermal solution, a simple, facile, and low-cost new strategy was demonstrated to prepare multi-channel surface-modified amorphous Fe 2 O 3 nanospheres as anodes for Li-ion batteries in this study. Compared with polycrystalline Fe 2 O 3 , the conversion reaction between amorphous Fe 2 O 3 and lithium ions has a lower Gibbs free energy change and a stronger reversibility, which can contribute to an elevation in the cycle capability of the electrode. Meanwhile, there are abundant active sites and more effective dangling bonds/defects in amorphous materials, which is beneficial to promote charge transfer and lithium-ion migration kinetics. The Galvanostatic intermittent titration analysis results confirmed that the amorphous Fe 2 O 3 electrode had a higher Li + diffusion coefficient. In addition, the surfaces of the amorphous nanospheres are corroded to produce multiple criss-cross channels. The multi-channel surface structure can not only increase the contact area between Fe 2 O 3 nanospheres and electrolyte, but also reserve space for volume expansion, thereby effectively alleviating the volume change during the intercalation-deintercalation of lithium ions. The electrochemical performance showed that the multi-channel surface-modified amorphous Fe 2 O 3 electrode exhibited a higher specific capacity, a more stable cycle performance, and a narrower voltage hysteresis. It is believed that amorphous metal oxides have great potential as high-performance anodes of next-generation lithium-ion batteries.