Preparation And Electrochemical Performance Of Metal Oxide And Graphene Composites

In this paper,two kinds of three-dimensional structures of tin dioxide and graphene composites and tricobalt tetroxide and graphene composites were designed and prepared by chemical methods.SEM,TEM,XRD,TG,XPS,N2 adsorption-desorption,FT-IR and Raman et al.Characterized the physical and chemical properties of the materials,and assembled them into coin-type batteries in an argon-filled glove box.The electrochemical performance of the materials was tested using a blue electricity system and an electrochemical workstation.The main results were obtained as follows.Three-dimensional(3D)hierarchical tin oxide Quantum Dots/graphene frameworks(SnO2 QDs@GF)were designed through anchoring the SnO2 QD on the graphene surface under hydrothermal reaction.The SnO2 QDs@GF have a 3D skeleton with a large number of mesopores and ultra-small SnO2 QDs,which greatly improves the stability of the three-dimensional structure and surface area.The unique design of this structure improves the specific area and promotes ion transport.The mechanically strong SnO2 QDs@GF can directly be used as the anode of LIB,it displays a high reversible capacity(1300 mAh g-1 at 100 mA g-1),excellent rate performance(642 mAh g-1 at 2000 mA g-1)and super long cycle stability(when the current density is 10A g-1,the capacity loss is less than 2%after 5000 cycles).This novel synthesis tactic can further be expanded to production of other quantum dots/graphene composites with 3D structure as high-performance electrodes for LIB.Based on graphene oxide,Co-MOF particles are uniformly grown on the surface by in-situ deposition method to obtain GO/Co-MOF by coordination,and then compacted on the surface of GO/Co-MOF by in-situ polymerization coated with conductive polyaniline and finally heat-treated to obtain polyaniline-coated three-dimensional graphene tricobalt tetroxide composite material(3D GF/Co3O4/PANI).It has been found that the polypyrrole-coated cobalt oxide particles grow uniformly on the graphene substrate,which greatly increases the surface area of the material.When used as the anode of the lithium-ion battery,it shows excellent electrochemical performance.At a current density of 100 mA g-1,the reversible capacity can reach 1152 mAh g-1 and at a current density of 8000 mA g-1.The power-down capacity is 312mAh g-1,which has excellent rate performance.This method provides good experimental data and theoretical support for the application of graphene-based polymer-coated metal-organic framework composites in the electrode materials of lithium ion batteries.