氧化石墨、碳纳米管掺杂活性炭、氮化碳的电化学性能研究

发布时间：2018-10-12 18:00

【摘要】：由于石油资源日趋短缺，并且燃烧石油的内燃机尾气排放对环境的污染越来越严重，促使人们研究替代石油的新型能源装置。对于化学电源的研究成为研究热点并取得了一定的成果，超级电容器以其优异的电特性而可以部分或全部替代传统的汽油用于车辆的牵引和启动。除此之外，超级电容器具有比传统的化学电池更加广泛的用途。在超级电容器研究中，开发高比容量的电极材料具有重要的应用价值和理论意义。目前超级电容器研究最多的是炭材料，如活性炭、介孔炭、炭纤维、碳纳米管、石墨烯等，但这些炭材料存在着各自的缺点。碳纳米管、石墨烯作为新型的炭材料受到人们的广泛关注。虽然碳纳米管、石墨烯是由石墨片层组成，并具有良好的导电、导热等性能，但其密度远小于石墨类材料。将碳纳米管、石墨烯与活性炭复合，发挥二者各自的优良特征，改进电极材料的导电性，将有利于获得高的能量密度和功率密度性能。氮化碳是人工合成的晶体材料，具有类似于石墨的片层结构、大的比表面积、强吸附能力、热稳定性好、这些优异性能使其在机械、光学和电子材料等领域有着广阔的潜在应用前景。本文研究的主要内容： (1)采用Hummer法，制备氧化石墨，并优化制备条件。结果表明，KMnO4和H2SO4用量对氧化石墨的形貌影响最大。加入量不足或过量都将使氧化石墨呈现絮状团聚体。电化学性能显示，氧化石墨具有良好的电容特征、功率放电和循环性能。 (2)在活性炭中分别添加氧化石墨和碳纳米管，考察氧化石墨和碳纳米管改进活性炭电极的导电性对电化学性能的影响。电化学性能测试结果显示，氧化石墨和碳纳米管对改进活性炭导电性的作用基本相似。电极导电性随着二者加入量的增加而增加，，电化学性能优于活性炭。当氧化石墨和碳纳米管的加入量为5wt%时，具有最好的电容特征、最大的响应电流密度、获得最大的容量。同时比较氧化石墨和碳纳米管的加入量为5wt%时，电化学性能的差别。发现碳纳米管对改进活性炭的电化学性能作用优于氧化石墨。 (3)以双氰胺为原料，制备块体和层状类石墨烯氮化碳。将其与碳纳米管复合，作为超级电容器的电极材料，分析其电化学性能。结果显示，N2吸附容量随着碳纳米管加入量的增加而增加。在块体氮化碳中加入50wt%碳纳米管，可获得最好的电化学性能；而在层状氮化碳中加入25wt%碳纳米管，可获得最好的电化学性能，表明层状氮化碳结构在应用方面将优于块体氮化碳。
[Abstract]:Because of the increasingly shortage of petroleum resources and the pollution of the environment caused by the exhaust gas from the combustion engine, people are studying new energy devices instead of oil. The research of chemical power supply has become a research hotspot and has achieved certain results. Because of its excellent electrical characteristics, supercapacitors can partly or wholly replace traditional gasoline for vehicle traction and start. In addition, supercapacitors have a wider range of uses than conventional chemical batteries. In the study of supercapacitors, the development of high specific capacity electrode materials has important application value and theoretical significance. At present, carbon materials, such as activated carbon, mesoporous carbon, carbon fiber, carbon nanotubes, graphene and so on, are the most studied supercapacitors, but these carbon materials have their own shortcomings. Carbon nanotubes (CNTs) and graphene (graphene) have attracted much attention as new carbon materials. Although carbon nanotubes graphene is composed of graphite laminates and has good conductivity and thermal conductivity its density is much smaller than that of graphite materials. Carbon nanotubes, graphene and activated carbon were combined to give play to their respective excellent characteristics and to improve the conductivity of electrode materials, which would benefit to obtain high energy and power density properties. Carbon nitride is a synthetic crystalline material, with a lamellar structure similar to graphite, large specific surface area, strong adsorption ability, good thermal stability, these excellent properties make it in mechanical, Optical and electronic materials and other fields have a wide range of potential applications. The main contents of this paper are as follows: (1) Graphite oxide was prepared by Hummer method and the preparation conditions were optimized. The results showed that the content of KMnO4 and H2SO4 had the greatest influence on the morphology of graphite oxide. Insufficient or excessive addition of graphite oxide will result in flocculent aggregates. Electrochemical properties show that graphite oxide has good capacitance, power discharge and cyclic properties. (2) addition of graphite oxide and carbon nanotubes into activated carbon, The effect of graphite oxide and carbon nanotubes on the electrochemical properties of activated carbon electrode was investigated. The results of electrochemical performance test showed that graphite oxide and carbon nanotubes had similar effects on improving the conductivity of activated carbon. The conductivity of the electrode increases with the increase of the content of the two, and the electrochemical performance is better than that of the activated carbon. When the addition amount of graphite oxide and carbon nanotube is 5 wt%, it has the best capacitance characteristic, the maximum response current density and the maximum capacity. At the same time, the difference of electrochemical properties of graphite oxide and carbon nanotubes was compared when the addition amount of graphite oxide and carbon nanotubes was 5 wt%. It was found that the electrochemical performance of carbon nanotubes was better than that of graphite oxide. (3) bulk and layered graphene nitride was prepared from dicyandiamide. Carbon nanotubes (CNTs) were used as electrode materials for supercapacitors and their electrochemical properties were analyzed. The results show that the N _ 2 adsorption capacity increases with the addition of carbon nanotubes. The best electrochemical performance can be obtained by adding 50wt% carbon nanotubes to bulk carbon nitride, and by adding 25wt% carbon nanotubes to layered carbon nitride. The results show that the structure of layered carbon nitride is better than that of bulk carbon nitride in application.
【学位授予单位】：辽宁科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM53

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