Transition metal oxides have been actively exploited for application in lithium ion batteries due to their facile synthesis,high specific capacity,and environmental-friendly.In this paper,Fe3O4@TiO2@C yolk-shell(Y-S)s...Transition metal oxides have been actively exploited for application in lithium ion batteries due to their facile synthesis,high specific capacity,and environmental-friendly.In this paper,Fe3O4@TiO2@C yolk-shell(Y-S)spheres,used as anode material for lithium ion batteries,were successfully fabricated by Stober method.XRD patterns reveal that Fe3O4@TiO2@C Y-S spheres possess a good crystallinity.But the diffraction peaks’intensity of Fe3O4 crystals in the composites is much weaker than that of bare Fe3O4 spheres,indicating that the outer anatase TiO2@C layer can cover up the diffraction peaks of inner Fe3O4 spheres.The yolk-shell structure of Fe3O4@TiO2@C spheres is further characterized by TEM,HAADFSTEM,and EDS mapping.The yolk-shell structure is good for improving the cycling stability of the inner Fe3O4 spheres during lithium ions insertion-extraction processes.When tested at 200 mA/g,the Fe3O4@TiO2@C Y-S spheres can provide a stable discharge capacity of 450 mAh/g over 100 cycles,which is much better than that of bare Fe3O4 spheres and TiO2@C spheres.Furthermore,cyclic voltammetry curves show that the composites have a good cycling stability compared to bare Fe3O4 spheres.展开更多
Fe3O4 nano-powder was prepared by the hydrothermal method. The structure and morphology of the product were characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The as-prepared powder has...Fe3O4 nano-powder was prepared by the hydrothermal method. The structure and morphology of the product were characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The as-prepared powder has regularly spherical morphology, and the average size of product is about 25 nm. The possible application use of this material as the active mass of anode for rechargeable Li batteries was examined by cyclic voltammeter (CV), galvanostatic charge/discharge.The experimental results showed that this material exhibited large specific capacity at the first cycle, and the discharge and charge capacity retention of this electrode are 37.04% and 48.76%, respectively. Furthermore, the impedance change of Fe3O4 electrode under different cycle number and potential was examined.展开更多
Iron oxide is a promising anode material for lithium ion batteries, but it usually exhibits poor electrochemical property because of its poor conductivity and large volume variation during the lithium uptake and relea...Iron oxide is a promising anode material for lithium ion batteries, but it usually exhibits poor electrochemical property because of its poor conductivity and large volume variation during the lithium uptake and release processes. In this work, a double protection strategy for improving electrochemical performance of Fe3O4 nanoparticles through the use of decoration with multi-walled carbon nanotubes and reduced graphene oxides networks has been developed. The resulting MWCNTs-Fe3O4-rGO nanocomposites exhibited excellent cycling performance and rate capability in comparison with MWCNTs-Fe3O4, MWCNTs-Fe3O4 physically mixed with rGO, and Fe3O4-rGO. A reversible capacity of -680 mA·h·g^-1 can be maintained after 100 cycles under a current density of 200 mA.g^-1.展开更多
Vanadium oxide Li3VO4 has attracted much attention as anode material for Li-ion batteries in recent years since it has a low and safe redox potential （vs. Li metal）, high specific capacity and its cost is low. Howev...Vanadium oxide Li3VO4 has attracted much attention as anode material for Li-ion batteries in recent years since it has a low and safe redox potential （vs. Li metal）, high specific capacity and its cost is low. However, the poor electronic conductivity and initial low coulombic efficiency limit its practical application. In this mini-review, the state-of-the-art results associated with Li3VO4 are summarized including structure, lithium insertion mechanism, preparation, modification, and electrochemical properties. Finally, the challenges and prospects are also discussed.展开更多
基金supported by the Tianjin Committee of Science and Technology (No.14JCZDJC32400)Tianjin Science and Technology Innovation Platform Program (No.14TXGCCX00017)
文摘Transition metal oxides have been actively exploited for application in lithium ion batteries due to their facile synthesis,high specific capacity,and environmental-friendly.In this paper,Fe3O4@TiO2@C yolk-shell(Y-S)spheres,used as anode material for lithium ion batteries,were successfully fabricated by Stober method.XRD patterns reveal that Fe3O4@TiO2@C Y-S spheres possess a good crystallinity.But the diffraction peaks’intensity of Fe3O4 crystals in the composites is much weaker than that of bare Fe3O4 spheres,indicating that the outer anatase TiO2@C layer can cover up the diffraction peaks of inner Fe3O4 spheres.The yolk-shell structure of Fe3O4@TiO2@C spheres is further characterized by TEM,HAADFSTEM,and EDS mapping.The yolk-shell structure is good for improving the cycling stability of the inner Fe3O4 spheres during lithium ions insertion-extraction processes.When tested at 200 mA/g,the Fe3O4@TiO2@C Y-S spheres can provide a stable discharge capacity of 450 mAh/g over 100 cycles,which is much better than that of bare Fe3O4 spheres and TiO2@C spheres.Furthermore,cyclic voltammetry curves show that the composites have a good cycling stability compared to bare Fe3O4 spheres.
基金Supported by the National Natural Science Foundation of China (Grant No. 20376086)
文摘Fe3O4 nano-powder was prepared by the hydrothermal method. The structure and morphology of the product were characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM). The as-prepared powder has regularly spherical morphology, and the average size of product is about 25 nm. The possible application use of this material as the active mass of anode for rechargeable Li batteries was examined by cyclic voltammeter (CV), galvanostatic charge/discharge.The experimental results showed that this material exhibited large specific capacity at the first cycle, and the discharge and charge capacity retention of this electrode are 37.04% and 48.76%, respectively. Furthermore, the impedance change of Fe3O4 electrode under different cycle number and potential was examined.
文摘Iron oxide is a promising anode material for lithium ion batteries, but it usually exhibits poor electrochemical property because of its poor conductivity and large volume variation during the lithium uptake and release processes. In this work, a double protection strategy for improving electrochemical performance of Fe3O4 nanoparticles through the use of decoration with multi-walled carbon nanotubes and reduced graphene oxides networks has been developed. The resulting MWCNTs-Fe3O4-rGO nanocomposites exhibited excellent cycling performance and rate capability in comparison with MWCNTs-Fe3O4, MWCNTs-Fe3O4 physically mixed with rGO, and Fe3O4-rGO. A reversible capacity of -680 mA·h·g^-1 can be maintained after 100 cycles under a current density of 200 mA.g^-1.
基金Acknowledgement Financial supports from National Materials Genome Project （No. 2016YFB0700600）, Natural Distinguished Youth Scientists Project of China （No. 51425301）, National Science Foundation Committee of China （Nos. 21374021 and U1601214） and Science and Technology Commission of Shanghai Municipality （No. 14520721800） are greatly appreciated.
文摘Vanadium oxide Li3VO4 has attracted much attention as anode material for Li-ion batteries in recent years since it has a low and safe redox potential （vs. Li metal）, high specific capacity and its cost is low. However, the poor electronic conductivity and initial low coulombic efficiency limit its practical application. In this mini-review, the state-of-the-art results associated with Li3VO4 are summarized including structure, lithium insertion mechanism, preparation, modification, and electrochemical properties. Finally, the challenges and prospects are also discussed.
