Long-cycle performance of the hollow and sandwich structured of H-TiO2/Fe3O4/C anode material for lithium-ion batteries
摘要
First, a spherical Fe3O4 was synthesized using the hydrothermal method, and subsequently coated with carbon to form a core–shell C/Fe3O4 composite. The Fe3O4 core was then dissolved in an etching solution to create a hollow carbon (H-C) structure. This H-C served as a substrate onto which a Fe3O4 layer was deposited via the hydrothermal method, resulting in a hollow core–shell Fe3O4/C composite. Finally, the solvothermal method was employed to coat the Fe3O4/C composite with a layer of hydrogenated titanium dioxide (H-TiO2), resulting in a hollow-structured H-TiO2/Fe3O4/C material. This structure not only ensures the formation of a dual-core shell structure, but also reduces the proportion of carbon material in the composite electrode, thereby enhancing the theoretical specific capacity of the composite electrode. The presence of H-TiO2 and carbon improved the cyclic stability of Fe3O4 within the composite. This hollow sandwich–structured composite demonstrated excellent electrochemical performance, delivering a discharge specific capacity of 629.5 mAh g−1 after 500 cycles at 0.2 A g−1, along with a high initial coulombic efficiency of 80.6%.