Preparation Of Transition Metal Oxide/graphene Composites And Their Lithium Storage Properties

Clean and renewable energy development and utilization,increasing people's demand for energy storage devices.As a high-performance energy storage devices,Lithium-ion battery research and therefore cause for concern.The transition metal oxide materials as the next generation of high-performance lithium-ion battery anode material aroused great interest research scientists in the field of energy storage devices.However,the transition metal oxide poor electrical conductivity,the charge-discharge process easy powdered shortcomings severely affected its performance improvement.In this thesis,excellent electrical conductivity and mechanical properties of large specific surface area of graphene as a conductive material and a support frame to form a composite material with two typical transition metal oxide,and a lithium-ion battery anode material,hoping to obtain excellent The electrochemical properties.The main work is as follows:(1)Preparation of an aqueous solution of graphene oxide with Hummers method.Graphene oxide were analyzed by X-ray diffraction,Raman scattering and transmission electron microscopy characterization testing.(2)Preparation of the first transition metal oxide Fe2O3 nanorods/graphene composites materials and Fe2O3 nanoparticles/graphene composites with hydrothermal method.And these two composite structure,morphology were characterized its anode materials for lithium-ion batteries charge and discharge characteristics and cycle stability were tested.Fe2O3 nanorods/graphene composites annealing before the first charge and discharge capacity of electrode is respectively 1014 and 1136 mA gh-1,annealing after the first charge and discharge capacity of electrode is respectively for 907 and 1278 mA h g-1.Fe2O3 nanoparticles/graphene composites the first charge and discharge capacity of electrode is respectively 692 and 886mA h g'1.(3)Preparation of the second transition metal oxide MnO nanoparticles/graphene composites with hydrothermal method.And these two composite structure,morphology were characterized its anode materials for lithium-ion batteries charge and discharge characteristics and cycle stability were tested.Composites annealing before the first charge and discharge capacity of electrode is respectively 661 and 642 mA h g-1,annealing after the first charge and discharge capacity of electrode is respectively 912 and 901 mA h g-1,constant current charge discharge cycle 80 times,before and after annealing were holding capacity is 549 mA h g-1 and 712 mA h g-1.