Hollow and sandwich structure of H-TiO2/Fe3O4/C for lithium battery anodes with long cycle performance
Firstly,the precursor spherical Fe3O4 was prepared by hydrothermal method,and the spherical Fe3O4 as the substrate was carbon coated to obtain core-shell Fe3O4@C composite.The Fe3O4 was dissolved in the etching solution by etching method,and the hollow structure C(H-C)material was obtained.Using the H-C as the substrate,a layer of Fe3O4 was coated on H-C material by hy-drothermal method to obtain the hollow core-shell structure Fe3O4/C material.Finally,the H-TiO2/Fe3O4/C composite with hollow sandwich structure was prepared by solvothermal method,which was coated with hydrogenated titanium dioxide(H-TiO2).H-TiO2 and C in the composite can improve the cyclic stability of Fe3O4.At the same time,the hollow structure reduces the proportion of C material(which has a low theoretical capacity)in the composite,and improves the intrinsic capacity of the H-TiO2/Fe3O4/C com-posite.The hollow sandwich H-TiO2/Fe3O4/C active material showed excellent electrochemical performance.After cycle 500 cycles the H-TiO2/Fe3O4/C active material is 629.5 mAh·g-1 at a current density of 0.2 A·g-1,and the most important thing was that the coulomb efficiency of the first cycle reached at amazing 80.6％.After cycle 1000 cycles the H-TiO2/Fe3O4/C specific capacity is 396.04 mAh·g-1 at a high current density of 1 A·g-1.
lithium ion batteryFe3O4hydrogenated TiO2hollowsandwich
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