The Application Of Graphene And Conducting Polymer Based Composites Materials In Electrochemical

With the rapid development of economy in our country,the demand of energy is increasing.Researching the appropriate energy storage devices such as electrochemical devices and applying them to practice become the key research objects.Lithium ion battery and supercapacitor are two hot spots in the current research.Lithium ion battery has advantages of high energy density,high discharge voltage and no memory effect.Supercapacitor has advantages of short charging time,high power density and environment friendly.So,the two devices have good application prospects.Our paper studied the application of graphene in lithium ion battery and the application of conducting polymers in supercapacitor.We compounded the graphene/conductive polymers with the mixed transition metal oxides and studied the electrochemical properties of composite materials.In the research of lithium ion battery anode materials,graphene oxide?GO?was used as raw materials.The reduction of graphene oxide load zinc molybdate composites?ZnMoO₄/rGO?was prepared by hydrothermal method.The ZnMoO₄/rGO composites were applied to lithium ion battery anode materials.The composition of composites was characterized by X-ray diffraction?XRD?,thermogravimetric analysis?TGA?and X-ray photoelectron spectroscopy?XPS?.The morphology of composites was observed by scanning electron microscopy?SEM?and transmission electron microscopy?TEM?.The electrochemical performance of ZnMoO₄/rGO composites was investigated by the galvanostatic charge–discharge technology.The initial discharge capacity was 2391.2mAh·g^-1 at a current density of 100 mA·g^-1.The research of rate performance was carried out at different current densities.The cyclic voltammetry?CV?and electrochemical impedance spectroscopy?EIS?measurements were performed by electrochemical workstation.In the research of electrode materials of supercapacitor,MnV₂O₆ and Cu₃?OH?₂V₂O₇·2H₂O were synthesized by hydrothermal methods respectively.Polypyrrole@MnV₂O₆ and polypyrrole@Cu₃?OH?₂V₂O₇·2H₂O composites were prepared via in situ polymerization methods.The polypyrrole?PPy?was deposited on the surface of MnV₂O₆ nanosheets and Cu₃?OH?₂V₂O₇·2H₂O nanowires.The composition and morphology of two kinds of composites were characterized by XRD,SEM,TEM and TGA test methods.The electrochemical performance was measured bycyclic voltammetry?CV?,galvanostatic charge/discharge and electrochemical impedance spectroscopy?EIS?measurements in a three-electrode system and two-electrode system.