Research On Preparation Of Cobalt?iron Oxide /graphene-carbon Nanotubes Composites For Lithium-stored Property

Since the transition metal oxide was found to be useful for lithium ion battery anode material,its theoretical specific capacity,simple preparation,non-polluting characteristics has been a hot spot for research.However its easy to reunite,low conductivity characteristics make the study focus on the carbon material composite to obtain uniform particles,small particle size of metal nanoparticles.In this paper,graphene-carbon nanotubes 3D carbon materials are used as load materials to obtain uniform cobalt and iron oxide nanoparticles on their surfaces,which improves the cycle performance and the rate performance of lithium ion batteries.The main contents are as follows:(1)Cobalt oxide/multi-layer graphene composites were prepared by hydrothermal method,which used expanded graphite and cobalt acetate tetrahydrate as raw materials.Then it was used as catalysts for growth of graphene-carbon nanotubes 3D carbon materials with CVD method.And their microstructures were characterized.(2)Cobalt oxide/graphene-carbon nanotubes composites were prepared by hydrothermal method,which used graphene-carbon nanotubes 3D carbon composite and cobalt acetate tetrahydrate as raw materials.Study the effects of the doping amount of cobalt ions on the morphology and storage properties of the products.The microstructural characterization and electrochemical performance of the composites were tested.The results show that with the increase of cobalt doping amount,the formation of flaky cobalt oxide on the surface of the three-dimensional carbon material increases the contact area between the electrode material and the electrolyte,which improves the lithium storage performance of the lithium ion battery.Reversible capacity of 677 m Ahg-1 can be delivered after 40 cycles at 100mAg-1 current density.(3)Iron oxide/graphene-carbon nanotubes composites were prepared by hydrothermal method.The effects of the loading of different substrates and iron oxides on the 3D carbon composite were also investigated.The microstructural characterization and electrochemical performance of the composites were tested.The experimental results show that Fe2O3/3D carbon composite shows a higher lithium storage capacity and rate performance than that of Fe2O3/FLGS and Fe2O3.Reversible capacity of 500mAhg-1 can be delivered after 50 cycles at 500 m Ag-1 current density.By reducing the iron oxide in the three-dimensional carbon material on the load,effectively improve the electrode material lithium storage performance.Reversible capacity of 780 m Ahg-1 can be delivered after 40 cycles at 100mAg-1 current density.