三维多孔碳纳米管海绵复合材料的可控制备和性能研究

发布时间：2018-10-13 18:20

【摘要】：碳纳米管海绵是一种由多壁碳纳米管无序堆积而成的三维多孔网络结构,在能源和环境领域有广阔的应用前景。为了推动碳纳米管海绵的实际应用,需要进一步改善它的力学和电学等相关性能,尤其是在形变过程中的结构稳定性和弹性回复能力。此外,在碳纳米管海绵内部可控的引入活性材料是制备高性能功能器件的有效途径。本论文研究了基于碳纳米管海绵的复合多孔材料的可控制备、力学性能和电容性能,探索了在能源器件领域的应用。通过在海绵内部均匀负载非晶碳和导电聚合物制备了结构可控的复合多孔材料,分别提高了海绵的力学性能和电化学性能。具体结果如下:制备了碳纳米管/非晶碳复合多孔材料并研究了力学性能。采用化学气相沉积法,乙炔为碳源,在海绵内部直接沉积非晶碳,获得了非晶碳均匀包覆的碳纳米管核壳结构。通过调节反应时间等参数调控了包覆层的厚度,并且碳纳米管之间的搭接点被有效焊接,形成了具有稳定三维框架的块体结构。力学测试表明,引入非晶碳使碳纳米管海绵的压缩弹性模量和压缩强度分别提高了40和60倍,在10%到50%的压缩应变下可弹性回复,循环压缩1000次后不产生塑性变形。分析了有关机制,发现碳纳米管的包覆及焊接能够保持材料在压缩过程中的结构稳定性,从而获得超弹性。制备了碳纳米管/聚苯胺复合多孔材料并研究了电化学性能。采用电化学沉积法,苯胺单体为原料,在碳纳米管海绵内部聚合成聚苯胺,获得了聚苯胺均匀包覆的碳纳米管核壳结构,并且聚苯胺的厚度可调,碳纳米管之间的搭接点也被焊接。采用三电极法测试了复合海绵的电化学性能,发现引入聚苯胺使质量比电容从约30 F/g提高到了753 F/g,高度压缩后仍能保持70%以上的质量比电容,同时体积比电容增加。通过在碳纳米管和聚苯胺之间引入聚吡咯层,显著提高了循环稳定性(1000次循环后保持90%以上)。碳纳米管的三维导电网络以及表面均匀包覆的赝电容材料是提高电化学性能的两个关键因素,在超级电容器领域有很好的应用前景。
[Abstract]:Carbon nanotube sponge (CNT) is a three-dimensional porous network composed of multi-walled carbon nanotubes (MCNTs), which is widely used in the field of energy and environment. In order to promote the practical application of carbon nanotube sponge, it is necessary to further improve its mechanical and electrical properties, especially its structural stability and elastic recovery ability during deformation. In addition, the controllable introduction of active materials into the carbon nanotube sponge is an effective way to fabricate high-performance functional devices. In this paper, the controllable preparation, mechanical properties and capacitive properties of composite porous materials based on carbon nanotube sponges are studied, and the applications in the field of energy devices are explored. Composite porous materials with controllable structure were prepared by uniformly loading amorphous carbon and conducting polymer in the sponge. The mechanical and electrochemical properties of the sponge were improved respectively. The results are as follows: carbon nanotube / amorphous carbon composite porous materials were prepared and their mechanical properties were studied. Amorphous carbon was deposited directly in the sponge by chemical vapor deposition with acetylene as the carbon source. The core-shell structure of carbon nanotubes coated uniformly with amorphous carbon was obtained. The thickness of the coating layer was adjusted by adjusting the reaction time and the lap joint between the carbon nanotubes was welded effectively to form a block structure with a stable three-dimensional frame. Mechanical tests show that the compressive elastic modulus and compressive strength of carbon nanotube sponges are increased by 40 and 60 times respectively with the introduction of amorphous carbon. Elastic recovery can be achieved at compression strain of 10% to 50%, and no plastic deformation is produced after 1000 cycles compression. The mechanism is analyzed and it is found that the coating and welding of carbon nanotubes can keep the structural stability of the material during compression process and obtain superelasticity. Carbon nanotubes / Polyaniline composite porous materials were prepared and electrochemical properties were studied. Polyaniline was polymerized into Polyaniline in carbon nanotube sponge by electrochemical deposition with aniline monomer as raw material. The core-shell structure of carbon nanotube coated with Polyaniline was obtained, and the thickness of Polyaniline was adjustable. Lap joints between carbon nanotubes are also welded. The electrochemical performance of composite sponge was measured by three-electrode method. It was found that the specific capacitance of composite sponge was increased from about 30 F / g to 753 F / g with the addition of Polyaniline, and the mass specific capacitance was still over 70% and the volume specific capacitance was increased after high compression. By introducing polypyrrole layer between carbon nanotubes and Polyaniline, the cycle stability was improved significantly (over 90% after 1000 cycles). The three-dimensional conductive network of carbon nanotubes and the uniformly coated pseudo-capacitor materials are two key factors to improve the electrochemical performance of carbon nanotubes and have a good application prospect in the field of supercapacitors.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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