Robust α-Fe(2)O(3)@TiO(2) Core–Shell Structures With Tunable Buffer Chambers for High-Performance Lithium Storage

α-Fe(2)O(3) has high potential energy storage capacity and can serve as a green and low-cost anode material for lithium-ion batteries. However, α-Fe(2)O(3) suffers large volume expansion and pulverization. Based on DFT calculations, TiO(2) can effectively maintain the integrity of the crystal structure during the discharge/charge process. Well-defined cubic α-Fe(2)O(3) is coated with a TiO(2) layer using the hydrothermal method with the assistance of oxalic acid surface treatment, and then α-Fe(2)O(3)@TiO(2) with tunable buffer chambers is obtained by altering the hydrochloric acid etching time. With the joint efforts of the buffer chamber and the robust structure of the TiO(2) layer, α-Fe(2)O(3)@TiO(2) alleviates the expansion of α-Fe(2)O(3) during the discharge/charge process. The optimized sample (FT-1h) achieves good cycling performance. The reversible specific capacity remains at 893.7 mA h g(-1), and the Coulombic efficiency still reaches up to 98.47% after 150 cycles at a current density of 100 mA g(−1). Furthermore, the reversible specific capacity can return to 555.5 mA h g(−1) at 100 mA g(−1) after cycling at a high current density. Hence, the buffer chamber and the robust TiO(2) layer can effectively improve the cycling stability and rate performance of α-Fe(2)O(3).