石墨烯多维结构构建及其超级电容性能研究

发布时间：2018-06-24 16:23

  本文选题：石墨烯 + 活性炭　； 参考：《燕山大学》2014年硕士论文

【摘要】：石墨烯作为碳材料的又一新同素异形体，具有巨大的研究、应用开发价值，有望成为超级电容器理想的电极材料。然而石墨烯基超级电容器有着其自身存在的问题有待研究。首先便不同的制备方法所获得的产物在形貌上存在着较大的差异，对石循环稳定性有着较大的影响；其次在制备过程中，片层之间存在的作用力使产物会发生团聚现象，实际获得的石墨烯的比表面积要远低于理论值，如何减少团聚且构建具备多级结构的石墨烯，从而使其提供的比容量尽可能向理论值靠近便成为当前研究的热点；最后制备石墨烯的成本就目前来说较高，而为了使石墨烯能够成为商业化应用的超级电容器电极材料，探索石墨烯和其它材料的复合材料便成为了可能的出路。本论文主围绕石墨烯基超级电容器主要展开以下研究工作。 采用水合肼处理和热膨胀两种不同的方法制备还原氧化石墨烯并对其循环稳定性加以研究。采用水合肼处理制备的产物rGO-Hz具有良好的循环稳定性；而采用热膨胀方法制备的产物rGO-T循环稳定性较差。分析了rGO-T循环稳定性较差的原因，是因为在循环过程当中，含氧官能团的消去使得rGO-T赝电容不断减少，且片层间发生团聚，最终导致其循环稳定性较差。 制备GO包覆的PS球作为前驱体并在不同温度下进行热处理得到具备多级结构的石墨烯。当热处理温度为700℃时，获得的样品HG7在0.5A/g的电流密度下比电容为162F/g，当电流密度提高至16A/g时，，其比电容仍然能达到112F/g，并且在各个电流密度下的比电容保持率都能达到90%以上；其拐点频率和等效内阻分别为12.598Hz和0.465，具有较快的电容响应速度和良好的导电性。 通过控制KAC和GO的质量比进行水热反应实现还原氧化石墨烯与活性炭复合材料的制备。当KAC与GO的质量比为2:1时，产物GKAC2的协同效应达到最大，具有最佳的电容行为和导电性的同时，比电容也达到最大值。电流密度为2A/g时，产物GKAC2在水系环境和有机体系下的比电容分别为205F/g和175F/g，当电流密度提高至16A/g时，其比电容分别为152F/g和143F/g。此外，产物GKAC2在有机体系下的功率密度和能量密度相比于水系环境下都有所提升，在1mol/LTEABF4/AN为电解液的有机体系，样品在16A/g的电流密度下功率密度和能量密度分别达到9.1kW/kg和26.3Wh/kg。因此制备石墨烯和活性炭的复合材料过程中，在提升石墨烯性能的同时大大降低了其生产成本。
[Abstract]:Graphene, as a new isomorphism of carbon materials, has great research and development value, and is expected to be an ideal electrode material for supercapacitors. However, graphene-based supercapacitors have their own problems to be studied. First of all, the products obtained by different preparation methods have great differences in morphology, which have a great influence on the stability of the stone cycle. Secondly, during the preparation process, the products will be agglomerated by the force between the layers. The specific surface area of graphene obtained is much lower than the theoretical value. How to reduce agglomeration and construct graphene with multilevel structure, so as to make the specific capacity of graphene as close as possible to the theoretical value has become the focus of current research. At last, the cost of preparing graphene is relatively high. In order to make graphene become a commercial electrode material for supercapacitor, it is possible to explore the composite materials of graphene and other materials. In this thesis, the following research work is mainly carried out around graphene-based supercapacitors. The redox graphene was prepared by hydrazine hydrate treatment and thermal expansion, and its cycle stability was studied. The products prepared by hydrazine hydrate treatment have good cyclic stability, while those prepared by thermal expansion method have poor cycle stability. The reason for the poor stability of rGO-T cycle is that the elimination of oxygen functional groups leads to the decrease of rGO-T pseudo-capacitance and the aggregation between the layers, which leads to the poor cycle stability of rGO-T. Go coated PS spheres were prepared as precursors and heat treated at different temperatures to obtain graphene with multilevel structure. When the heat treatment temperature is 700 鈩

本文编号：2062142