Oxygen vacancy-rich Fe3O4 nanoparticle synthesized via facile electrochemical method as anode material for high-performance lithium-ion batteries

Oxygen vacancies (Ov), which are internal defects of metal oxides, can effectively alter intrinsic properties of materials. Developing an anode material containing Ovs applied in lithium-ion batteries (LIBs) was hypothesized to enhance their electrochemical performance, which has currently attracted extensive attention. Herein, we successfully synthesized three groups of Fe3O4 nanoparticles with different Ov concentrations by a facile and controllable electrochemical oxidation corrosion method. First, density functional theory was applied to predict the Li-ion storage performance and electronic properties of pristine Fe3O4 and the synthesized different Ov-content Fe3O4 materials. When used as an anode material in LIBs, all the three as-prepared Ov-rich Fe3O4 electrodes possessed excellent cycling performance and high reversibility. After 330 cycles, the reversible ca-pacity achieved 745 mAh g-1, 921 mAh g-1, and 850 mAh g-1, respectively. Ovs in the Fe3O4 not only promote high electronic conductivity in the materials, but also afford additional active sites for lithiation and delithiation, further enhancing the electrochemical performance. However, excessive Ovs are not conducive to the improvement of lithium storage capacity. Theoretical predictions and experimental results are consistent with each other. This work has great importance in the direction of oxygen defect applications in the field of LIBs.