氧化石墨热还原及石墨烯-硫化物超电容性能研究

发布时间：2018-04-06 20:06

本文选题：石墨烯　切入点：硫化铜　出处：《中国矿业大学》2017年硕士论文

【摘要】：石墨烯因其独特的物理化学性能在储能材料领域具有广阔的应用前景,近年来石墨烯基超级电容器复合材料已经成为储能材料研究领域的研究热点。本文采用氧化-热还原法将石墨先氧化成氧化石墨,在空气中对氧化石墨进行快速加热,使其片层发生剥离和还原,制得石墨烯粉末,并通过X射线衍射(XRD),红外光谱(FT-IR),拉曼光谱(Raman),X射线光电子能谱(XPS),透射电镜(TEM)等表征手段讨论快速热还原对样品还原程度的影响。在此基础之上,采用一步水热法分别制备了硫化铜-石墨烯复合材料和多相镍硫化物-石墨烯复合材料,并表征了复合材料的结构和成分,讨论了复合材料作为超级电容器电极活性材料的电化学电容性能。主要研究内容和结论如下:1.采用热板作为热源,在空气中将氧化石墨粉直接喷向热板进行还原,使得样品的制备十分迅速。样品的结构和成分分析表明,随着温度的升高,氧化石墨的结构逐渐向石墨烯的结构进行转变。在快速热还原过程中,氧化石墨的片层堆叠结构发生剥离和还原,形成石墨烯的微晶结构。比表面积和孔径分析表明,这种还原产物具有高达737 m2?g-1的比表面积和0.70 cm3?g-1?nm-1的孔体积。这种制备方法对于实现石墨烯大规模工业化生产具有重要的借鉴意义。2.在快速热还原制备石墨烯的基础上,采用一步水热法在石墨烯基底上生长出花球状硫化铜微球,改善了以有机溶剂作为反应溶剂的方法,是一种环境友好的制备工艺。电化学电容性能测试表明,在1 A?g-1时比容量最高可达1222.5F?g-1,并且在5 A?g-1时连续循环3000次后,电容保持率达到92.11%。3.利用水热法制备了多相镍硫化物-石墨烯复合材料,在石墨烯表面负载的镍硫化物微球为多种镍硫化物(NiS,NiS2和Ni3S4)的混合相。探讨了反应温度和时间对产物的结构与成分的影响,并将这种复合材料应用于超级电容器电极活性材料。电化学电容性能测试表明,在1 A?g-1时比容量可达1602.2 F?g-1,并具有良好的倍率特性与循环稳定性(循环3000次后的电容量保持率为90.81%)。
[Abstract]:Graphene has a wide application prospect in the field of energy storage materials because of its unique physical and chemical properties. In recent years, graphene based supercapacitor composites have become a research hotspot in the field of energy storage materials.In this paper, graphite was oxidized to graphite oxide by oxidation-thermal reduction method. Graphite oxide was heated rapidly in air, and its lamellar layer was stripped and reduced to produce graphene powder.The effects of rapid thermal reduction on the reduction degree of the samples were discussed by means of X-ray diffraction (XRD), FTIR (FT-IRT), Raman spectroscopy (Ram), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM).On this basis, copper sulphide graphene composites and polyphase nickel sulfide-graphene composites were prepared by one-step hydrothermal method, and the structure and composition of the composites were characterized.The electrochemical capacitance performance of composite material as electrode active material of supercapacitor was discussed.The main contents and conclusions are as follows: 1.Using hot plate as heat source, the oxidized graphite powder was sprayed directly into the hot plate in air, which made the preparation of the sample very rapid.The structure and composition analysis of the samples showed that the structure of graphite oxide gradually changed to that of graphene with the increase of temperature.In the process of rapid thermal reduction, the lamellar stacked structure of graphite oxide is stripped and reduced to form the microcrystalline structure of graphene.The specific surface area and pore size analysis showed that the reduction product had a specific surface area of 737 m2?g-1 and a pore volume of 0.70 cm3?g-1?nm-1.This preparation method has important reference significance for realizing the large-scale industrial production of graphene.On the basis of rapid thermal reduction to prepare graphene, copper sulfide microspheres were grown on graphene substrate by one step hydrothermal method, which improved the method of using organic solvent as reaction solvent and was an environmentally friendly preparation process.The electrochemical capacitance performance test shows that the maximum specific capacity can reach 1222.5 FU g-1 at 1 A?g-1, and the capacitance retention rate reaches 92.11.1 after 3000 continuous cycles at 5 A?g-1.Multiphase nickel sulfide-graphene composites were prepared by hydrothermal method. The nickel sulfide microspheres supported on the surface of graphene were mixed with various nickel sulfides, NiS _ 2 and Ni _ 3S _ 4).The effects of reaction temperature and time on the structure and composition of the product were discussed, and the composite was applied to the electrode active material of supercapacitor.The electrochemical capacitance performance test shows that the specific capacity can reach 1602.2 FG-1 at 1 A?g-1, and has good rate characteristics and cycle stability (the capacitance retention rate of 3000 cycles is 90.81%).
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM53;TQ127.11;TB332

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