Halide-Ion-Assisted Synthesis of Different α-Fe₂ O₃ Hollow Structures and Their Lithium-Ion Storage Properties

Various α-Fe₂ O₃ hollow structures, such as wormlike shapes, ellipsoids, and quasicubes, were synthesized successfully by a halide-ion-assisted solvothermal method. The self-assembly assisted by selective absorption of halide ions and Ostwald ripening speeded up by acidic etching commonly determine the final unique structures. The electrochemical performance of the α-Fe₂ O₃ with different structures in reversible lithium-ion storage was investigated, and showed that the hollow Fe₂ O₃ quasicubes exhibit the best cycling performance with a charge capacity of 401.6 mAh g^-1 after 100 cycles at 0.2 C. The superior cycling stability and high specific capacity can be ascribed to the higher specific surface area, lower charge-transfer resistance, and adequate alleviation of volume variation.