三维氮掺杂石墨烯的制备及其电化学性能研究
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摘 要
石墨烯是由单层碳原子以 sp2杂化紧密堆积而成的六方蜂窝状二维原子晶体，
是目前最为理想的二维纳米材料，也是一种新型碳材料，因具有良好的电荷传输
性能和超高的表面积等独特性质，广泛应用于超级电容器、燃料电池和锂离子电
池等储能器件。将石墨烯制备成三维多孔结构不仅能够实现从纳米材料研究到宏
观实际应用的转变，而且可以在一定程度上解决石墨烯的团聚问题。此外，将石
墨烯进行氮掺杂可以有效调控石墨烯的电子结构和化学性质，制备出的材料表现
出许多优异性能，是一种促进石墨烯实际应用的行之有效的方法。因此，本论文
利用一种简单的方法-水热法一步实现三维氮掺杂石墨烯的制备，利用扫描电子显
微镜和低温氮气吸-脱附分析了解材料的微观形貌和孔结构；利用红外光谱、拉曼
光谱、X射线粉末衍射和 X射线光电子能谱研究材料的结构和组成；利用循环伏
安、恒电流充放电和交流阻抗测试考察材料的电化学性能。具体如下：
1. 从氧化石墨烯出发，以吡咯单体作为还原剂和掺氮剂，采用水热法实现氮
掺杂石墨烯的三维自组装。首先以三维氮掺杂多孔石墨烯水凝胶为模型，将其经
过三种不同的干燥方式处理，考察了干燥方式对三维石墨烯结构和性能的影响。
结果表明，干燥方式对材料的孔结构影响很大，将石墨烯水凝胶直接冷冻干燥可
以得到连续三维多孔结构，而经过预先冷冻，然后再冷冻干燥得到的样品则具有
松散的层状堆叠结构，加热干燥的样品为类石墨的紧密堆积层状结构。直接冷冻
干燥样品具有最高的比电容和最好的电容倍率性能，比电容为 218 F/g，在电流密
度为 1 A/g 时，仍然能够保持较高的比电容值，约为 185 F/g，为初始比电容的 85%。
2．吡咯的添加量也是影响三维氮掺杂石墨烯的结构和电化学性能的重要因
素，因此，固定干燥条件为直接冷冻干燥，通过改变材料制备过程中吡咯的加入
量考察氮掺杂量对材料结构和电化学性能的影响。结果表明，随着氮含量的增加，
材料微米级的大孔没有明显改变，但是比表面积显著降低，从 361 降到 37 m2/g，
且氧化石墨烯与吡咯的质量比为 1:2 的材料表现出较好的电化学性能，比电容高达
218 F/g。
3. 为了进一步解决石墨烯在水热过程中的团聚问题，制备了三维氮掺杂石墨
烯/碳纳米管复合材料。结果表明碳纳米管可以有效地解决石墨烯在水热过程中的
团聚问题，增加了石墨烯片层间距和材料的比表面积，当碳纳米管的含量为 5%时，
材料的 BET 比表面积高达 597 m2/g。与此同时，嵌入的碳纳米管不仅能够解决氮
掺杂石墨烯的团聚问题，还能够提高材料的导电性，与相同条件下制备的氮掺杂
三维石墨烯比，制备的三维氮掺杂石墨烯/碳纳米管复合材料表现了良好的电化学
性能，具有较低的内阻和较高的比电容（比电容为 284 F/g）。
关键词：石墨烯 氮掺杂 水热法 碳纳米管 超级电容器
ABSTRACT
Graphene, a two-dimensional atomic crystal, is composed of monolayer carbon atoms
which are densely packed into a honeycomb structure by sp2 hybridization. Graphene is
not only the optimal two-dimensional nanomaterial, but also a kind of new carbon
materials. Due to its unusual electronic transport properties and high specific surface
area, graphene has been widely used in supercapacitors, fuel cells and lithium ion
batteries, etc. The three-dimensional porous structure of graphene can not only realize
the transformation from nanomaterials research to macro practical application, but also
solve the aggregation of graphene to a certain extent. Furthermore, doping nitrogen is a
practical way to tailor graphene electronic structure, improve its physical and chemical
properties, and facilitate its practical applications. Therefore, a simple hydrothermal
method was used to realize the preparation of N-doped graphene in this paper. Scanning
electron microscopy and N2 adsorption/desorption method were used to analysis
microstructure and pore structure of the materials. Fourier transform infrared
spectroscopy, raman spectra, X-ray powder diffraction and X-ray photoelectron
spectroscopy were used to study the structure and composition of the materials. And
their electrochemical performance were measured by cyclic voltammetry(CV),
galvanostatic charge/discharge(GCD) methods and electrochemical impedance
spectroscopy(EIS) test. The main results were summarized as follows:
1. Using graphene oxide as initial material, and pyrrole as reducing/nitrating agents.
Hydrothermal method was used to realize the three-dimensional self-assembly of
graphene. Using three-dimensional N-doped porous graphene as model material, then
the samples were treated in three different drying methods. The influence of drying
methods for the structure and performance of materials was investigated. The results
showed that each layer of PFD contained several layers of graphene sheets. On the
contrary, when the sample was freeze dried directly, three-dimensional interconnected
frameworks with randomly opened pores were formed. When the sample was heat dried,
tightly packed layers were formed. DFD had the highest specific capacitance(218 F/g)
and the best capacitance ratio performance. When the current density was 1 A/g, DFD
still could maintain a higher specific capacitance value(185 F/g), which was 85% of the
initial specific capacitance.
2. The content of pyrrole is also an important factor for the structure and
electrochemical properties of three-dimensional N-doped graphene. Therefore, fixing
the drying condition as freeze-drying directly, the influence of pyrrole amount on the
structure and electrochemical properties of materials was studied. The results showed
that micron grade macropores of materials had no obvious change with the increase of
the content of pyrrole, but the specific surface area decreased significantly, which
droped from 361 to 37 m2/g. When the quality ratio of graphene oxide and pyrrole was
1:2, the material exhibited good electrochemical performance and the specific
capacitance was 218 F/g.
3. Three-dimensional N-doped graphene/CNTs can further solve the problem of
graphene aggregation during the hydrothermal process. The results showed that CNTs
could effectively prevent the graphene from aggregating, and improve the spacing
between two layers and specific surface area of graphene. When the content of CNTs
was 5%, the BET specific surface area of material could reach 597 m2/g, at the same
time, the embedded CNTs could improve the electrical conductivity of the materials.
The three-dimensional N-doped graphene/CNTs showed good electrochemical
performance as well as low resistance, and the specific capacitance was as high as 284
F/g.
Key Word: graphene, N-doped, hydrothermal method, carbon
nanotubes, supercapacitor
目 录
中文摘要
ABSTRACT
第一章 绪 论..................................................................................................................1
1.1 石墨烯的发现.......................................................................................................1
1.2 石墨烯的结构及性质……………………………………………………….......1
1.3 石墨烯的制备方法……………………………………………………………...2
1.3.1 机械剥离法…………………………………………………………………..2
1.3.2 外延生长法…………………………………………………………………..3
1.3.3 化学气相沉积法……………………………………………………………..3
1.3.4 化学合成法…………………………………………………………………..4
1.3.5 氧化还原法…………………………………………………………………..4
1.4 三维石墨烯的制备方法………………………………………………………...6
1.4.1 抽滤法………………………………………………………………………..6
1.4.2 化学气相沉积法……………………………………………………………..7
1.4.3 水热法………………………………………………………………………..8
1.5 石墨烯的改性…………………………………………………………………...8
1.6 石墨烯在超级电容器领域的应用……………………………………………...9
1.6.1 双电层电容器的工作原理………………………………………………….10
1.6.2 赝电容电容器的工作原理………………………………………………….10
1.6.3 基于石墨烯的超级电容器研究进展……………………………………….10
1.7 课题意义和研究内容…………………………………………………………..11
第二章 实验部分……………………………………………………………………...13
2.1 实验试剂及仪器………………………………………………………………..13
2.1.1 实验试剂…………………………………………………………………….13
2.1.2 实验仪器…………………………………………………………………….13
2.2 材料的表征……………………………………………………………………..14
2.2.1 场发射扫描电子显微镜……….……………………………………………14
2.2.2 傅里叶变换红外光谱……………….………………………………………14
2.2.3 激光拉曼光谱…………..…………………………………………………...14
2.2.4 X 射线衍射…………...………………………………………………………15
2.2.5 X 射线光电子能谱……………...…………………………………………....15
2.2.6 氮气吸-脱附测试……………………………………………………………15
2.2.7 电化学性能测试…………………………………………………………….15
第三章 三维氮掺杂石墨烯的制备及其电化学性能……………………………...…18
3.1 干燥方式对三维氮掺杂石墨烯结构和电化学性能的影响…………………..18
3.1.1 实验………………………………………………………………………….19
3.1.2 结果与讨论………………………………………………………………….21
3.2 氮掺杂量对材料结构和电化学性能的影响…………………………………..30
3.2.1 实验………………………………………………………………………….30
3.2.2 结果与讨论………………………………………………………………….30
3.3 小结……………………………………………………………………………..35
第四章 三维氮掺杂石墨烯/碳纳米管的制备及其电化学性能……………………..36
4.1 实验……………………………………………………………………………..36
4.1.1 三维氮掺杂石墨烯/碳纳米管的制备………………………………………36
4.1.2 电极的制备及组装………………………………………………………….37
4.2 结果与讨论……………………………………………………………………..37
4.2.1 碳纳米管含量对材料孔结构的影响……………………………………… 37
4.2.2 碳纳米管含量对材料电化学性能的影响………………………………….40
4.3 小结……………………………………………………………………………..42
第五章 结论………..………………………………………………………………… 43
参考文献……………………………………………………………………………….44
在读期间公开发表的论文和承担科研项目及取得成果…………………………….50
致谢…………………………………………………………………………………….51
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作者：侯斌
分类：高等教育资料
价格：15积分
属性：55 页
大小：4.07MB
格式：PDF
时间：2025-01-09
