Synthesis Of Hybrid Materials Based On Graphene And Their Perfermances In Libs And SCs

The thesis mainly contains three parts of works: the synthesis andreduction of graphene oxide, the synthesis of graphene/Fe₃O₄、graphene/TiO₂and their properties as an anode materials for lithium ionbatteries, the synthesis of graphene/Ni-Al LDH and its properties asadvanced electrochemical pseudocapacitor material.GO is made by an improved Hummers method followed bysupersonic progress. Graphene/FeOOH hybrid composite is prepared bysolvothermal method, in which the aqueous solution of GO andisopropanol act as a solvent and FeCl3as the crystal seeds. Then heat thegraphene/FeOOH hybrid composite at600℃in the inert atmosphere for4-5h and get the product of graphene/Fe₃O₄. The product structure isconfirmed by SEM, TEM and XRD characterizations. Cycled between1and3V at35mA g^-1demonstrates a first discharge capacity of1250mAh g^-1, after30cycles the capacity is also930mAh g^-1, the hybridmaterial realize a high capacity and good cycling performance.Graphene/TiO₂hybrid composite is prepared by solvothermal method, in which the glycol solution of GO and acetic acid act as asolvent and tetrabutyl titanate as the crystal seeds. In the Teflon reactorhydrolysis of titanium tetrachloride and esterification occursimultaneously. The product structure is confirmed by SEM, TEM andXRD characterizations. Cycled between1and3V at30mA g^-1demonstrates a first discharge capacity of196mAh g^-1, after50cycles thecapacity is also100mAh g^-1a, the hybrid material realize a high capacityand good cycling performance.Moreover, we get Ni-Al LDHs/graphene hybrid material bysolvothermal method in180℃for48h. The product structure isconfirmed by SEM, TEM, HRTEM and XRD characterizations and thendeposite it in nickel foam sheet by PVDF for testing. In the CV cruves,the hybrid shows two redox peaks correspond to two differentNi（II）/Ni（III）. The hybrid material performances good electrochemicalcharacteristics as pseudocapacity with a capacitance of486F·g^-1。We alsostudy the CV and Discharge cruves of the hybrid material with differentnickel and aluminum rato. The results show that the hybrid material hasthe best performance with the nickel and aluminum rato at3.