基于锰氧化物和石墨烯材料的超级电容器性能研究

发布时间：2018-04-12 06:20

本文选题：石墨烯 + 锰氧化物　；参考：《北京交通大学》2014年硕士论文

【摘要】：进入21世纪,能源的日益枯竭和环境污染问题越来越严重,发展风能、太阳能等新能源和电动汽车成为全世界的共识,因此发展新型的高性能能量存储装置越来越迫切。超级电容器作为一种介于电池和传统电容器之间的新型储能装置,具有高的功率密度,长的循环寿命,高的放电效率,较宽的温度适用范围,环境友好性,安全性,易维护等优异性能而成为储能领域的研究热点。超级电容器能量密度较低,是限制其商业化发展的最大因素。目前超级电容器的研究,主要是探索和改善高性能电极材料,从而提高超级电容器的能量密度。本文选定高表面积、高导电性的石墨烯和廉价的锰氧化物作为超级电容器的电极材料,结合多种材料表征测试方法和电化学性能测试的研究手段,研究了合成的电极材料的相关性能。本文主要研究成果如下 (1)提出一种新的液相的沉淀法,合成了纳米Mn3O4颗粒和Mn3O4／石墨烯复合材料,并对材料进行了XRD、TEM、SEM和电化学性能表征；得到的复合材料中,Mn3O4颗粒均匀分散在石墨烯片层上,使得Mn3O4赝电容得到更有效地利用,石墨烯能极大地改善体系的导电性。Mn3O4/石墨烯复合材料在表现出140F/g的比电容(10mV/s下),经过1000次循环后仍保持约96%的容量,展现出极好的循环稳定性。 (2)利用乙醇还原高锰酸钾的方法,制备了纳米MnO2,并且将纳米Mn02与石墨烯／碳纳米管体系复合。合成的MnO2/GNS/CNTs三元复合材料展现出优异的电化学性能,尤其是其倍率性能和循环稳定性。在MnO2/GNS/CNTs复合材料中的Mn02成分在5mV/s的扫描速率下最大表现出240F/g的比电容,远大于纯MnO2电极(192F/g)的比电容。 (3)为了进一步优化MnO2/GNS/CNTs三元复合材料体系中,研究了不同的GNS/CNTs比例对电化学性能的影响。组装了对称的超级电容器,最大的能量密度为11.9Wh/kg,优于商用活性炭超级电容器(一般小于5Wh/kg)。
[Abstract]:In the 21st century, the problem of energy depletion and environmental pollution is becoming more and more serious. The development of new energy sources such as wind energy, solar energy and electric vehicles has become a consensus all over the world. Therefore, the development of new high-performance energy storage devices is becoming more and more urgent.As a new energy storage device between batteries and conventional capacitors, supercapacitors have high power density, long cycle life, high discharge efficiency, wide temperature range, environmental friendliness and safety.Easy maintenance and other excellent performance has become a research hotspot in the field of energy storage.The low energy density of supercapacitors is the biggest factor limiting the development of their commercialization.At present, the research of supercapacitors is mainly to explore and improve the high performance electrode materials, so as to improve the energy density of supercapacitors.In this paper, graphene with high surface area and high conductivity and cheap manganese oxide are selected as electrode materials for supercapacitors.The properties of the synthesized electrode materials were studied.The main research results of this paper are as follows(1) A new liquid phase precipitation method was proposed to synthesize nano-sized Mn3O4 particles and Mn3O4/ graphene composites, which were characterized by SEM and electrochemical properties, and the particles of mn _ 3O _ 4 in the composites were uniformly dispersed on graphene lamellae.The pseudo-capacitance of Mn3O4 can be utilized more effectively, and graphene can greatly improve the conductivity of the system. Mn _ 3O _ 4 / graphene composite shows the specific capacitance of 140F/g at 10 MV / s, and maintains the capacity of about 96% after 1000 cycles.Show excellent cyclic stability.Nanocrystalline MNO _ 2 was prepared by reducing potassium permanganate by ethanol, and nanosized Mn02 and graphene / carbon nanotube system were prepared.The synthesized MnO2/GNS/CNTs ternary composites exhibit excellent electrochemical properties, especially their rate performance and cyclic stability.The Mn02 composition in the MnO2/GNS/CNTs composite exhibits the maximum specific capacitance of 240F/g at the scanning rate of 5mV/s, which is much larger than that of the pure MnO2 electrode (192F / g).In order to optimize the electrochemical properties of MnO2/GNS/CNTs ternary composites, the effects of different GNS/CNTs ratios on electrochemical properties were studied.Symmetrical supercapacitors were assembled with a maximum energy density of 11.9 Whs / kg, which is superior to commercial activated carbon supercapacitors (typically less than 5 Whs / kg 路kg ~ (-1) 路kg ~ (-1)).
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TQ127.11;TM53

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