基于聚多巴胺的新型碳材料的制备及其电化学性能研究

发布时间：2018-01-25 19:08

  本文关键词： 聚多巴胺 氮掺杂 多孔碳材料 能量存储 超级电容器　出处：《长春工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：多孔碳材料由于高的比表面积,优异的电子传导率,良好的化学稳定性等优点在超级电容器的电极材料领域被广泛研究。但与其他类型的电极材料如金属氧化物和导电聚合物相比,基于碳的电极材料的比电容和能量密度仍然较低。为了提高多孔碳材料的电化学性能,一种有效的方法是向材料中引入杂原子和官能团。例如掺杂氮原子,与单纯的多孔碳材料相比,氮掺杂能提高材料的电导率和湿润性,但制备过程耗时,或有危险,活化过程容易对环境造成污染。因此,研究制备过程无污染,电化学性能好的多孔碳材料对电极材料的发展有重要意义。氮掺杂的多孔碳材料做电极材料时主要是通过电荷在电极表面的积累以及材料表面的含氮官能团的氧化还原反应来存储电荷,具有比表面积大,循环稳定性好等特点。但这类材料往往氮掺杂率较低,制备过程繁琐且污染环境,限制了其实际应用。本文首先利用生物小分子多巴胺在碱性条件下自聚合形成650±38nm平均粒径的聚多巴胺(polydopamine,PDA)球,然后在活化剂KOH存在下高温煅烧PDA球制备出了氮掺杂多孔碳材料,避免了氮掺杂的复杂过程和硬模板的应用。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线粉末衍射(XRD)、X-射线光电子能谱(XPS)和Raman光谱等对所制备的氮掺杂多孔碳材料进行了形貌及结构组成的表征。系统研究了煅烧温度对材料结构组成、孔特性及电化学性能的影响。利用KOH做活化剂700℃高温碳化后,制备出的碳材料PDA-KOH-700比表面积和孔体积分别可达到1469.49 m2g-1和0.8527 cm3g-1。在6mol·L-1KOH电解液中,采用循环伏安、恒电流充放电对多孔碳材料的电化学性能进行了研究。结果表明,由于双电层电容和赝电容的协同作用,在电流密度为1 A·g-1时比电容可达到269 F·g-1,充放电循环1000圈后电容仍可保留初始值的93.5%,并且大功率密度下仍然保持较高的能量密度。这些结果表明,PDA-KOH-700在应用于超级电容器电极材料方面有很好的前景。
[Abstract]:Porous carbon materials have excellent electron conductivity due to their high specific surface area. The advantages of good chemical stability have been widely studied in the field of electrode materials for supercapacitors, but compared with other types of electrode materials such as metal oxides and conductive polymers. The specific capacitance and energy density of carbon-based electrode materials are still low. In order to improve the electrochemical performance of porous carbon materials, an effective method is to introduce hetero-atoms and functional groups into the materials, such as doped nitrogen atoms. Compared with the pure porous carbon materials, nitrogen doping can improve the conductivity and wettability of the materials, but the preparation process is time-consuming or dangerous, the activation process is easy to pollute the environment. Therefore, the preparation process has no pollution. Porous carbon materials with good electrochemical properties are of great significance to the development of electrode materials. Nitrogen doped porous carbon materials are mainly used as electrode materials through the accumulation of charge on the electrode surface and the oxygen of nitrogen-containing functional groups on the surface of the materials. The reduction reaction to store the charge. This kind of material is characterized by large surface area and good cycling stability. However, this kind of material often has low nitrogen doping rate, cumbersome preparation process and pollution of the environment. The practical application of dopamine was limited. Firstly, polydopamine with 650 卤38 nm average particle size was synthesized by self-polymerization of biological small molecule dopamine in alkaline condition. Nitrogen doped porous carbon materials were prepared by calcining PDA spheres at high temperature in the presence of activator KOH. The complex process of nitrogen doping and the application of hard template are avoided. By means of scanning electron microscope (SEM) and transmission electron microscope (TEM), the X-ray powder diffraction (XRD) is carried out. X-ray photoelectron spectroscopy (XPS) and Raman spectra were used to characterize the morphology and structure of nitrogen-doped porous carbon materials. The effect of pore characteristics and electrochemical properties. KOH was used as activator after high temperature carbonization at 700 鈩，

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