蒽醌及其衍生物非共价功能化还原氧化石墨烯的制备与超电容性能

This project will use anthraquinone or its derivatives as guest molecules to functionalize non-covalently reduced graphene oxide (RGO). The host and guest molecules are parallel to each other due to π-π interaction between the aromatic ring and sp2 network of RGO and form a new composite structure consisting of two conjugated systems. When the composite is used as an electrode of supercapacitors, it will reveal higher overall capacitance than the bare RGO because of the superposition between pseudocapacitance and electric double-layer capacitance. In addition, the skeleton of anthraquinone and its derivatives is not destroyed during charging and discharging processes, which is beneficial to maintain the long stability of electrochemical cycling. The project will also detect the maximum electron numbers which transfer in the redox of single anthraquinone derivative with electrochemical reversibility, explore how they are related to super capacitance and recognize their complex electrode process kinetics. Furthermore, the project will regulate and control the interaction between host and guest molecules through the introduction and distribution of nucleophilic or electrophilic groups on the anthraquinone ring as well as the doping of RGO, resulting in the low charge transfer resistance and high electrochemical conversion rate of energy. Finally, we will use the resultant materials to prepare the electrode of supercapacitors, select proper electrolytes and cell voltage according to the measured results in the three-electrode systems and assemble practical supercapacitors by matching the positive and negative electrodes. We will also measure the energy and power density of the assembled supercapacitors in order to evaluate their capacitive performance.

本课题拟选取蒽醌及其衍生物作为客体分子非共价功能化还原氧化石墨烯（RGO），π-π作用使主体与客体分子平行共存，形成新型共轭体复合结构。这种复合体用作超级电容器电极将产生赝电容和双电层电容的叠加效应，可提供比纯RGO更高的总电容。此外，蒽醌及其衍生物在进行充放电循环时，其分子骨架不易被破坏，有望维持超长的循环稳定性。课题研究将探知单个蒽醌衍物在维持电化学可逆性的前提下所能承载的最多电子转移数以及它们与超电容之间的关系，并认识其复杂电极过程动力学；通过蒽醌环上给或吸电子基团的引入与布局，或借助RGO的掺杂等方式调配主客体之间的作用力行为，降低其电荷传递阻力，提高其电化学能量转化速率。最终，用合成的电极材料制作超级电容器电极，并根据它们在三电极体系下的电势数据，选择适当的电解质体系和电位窗口，合理匹配正负极进行类商业型电容器的组装，测试其能量和功率密度方面数据，对目标电容器的性能做出科学评价。

课题研究通过非共价键修饰的方法，在不破坏还原氧化石墨烯（RGO）的sp2杂化体系的前提下把多种具有电化学活性基团的有机分子引入到RGO表面，形成新型的有机分子储能电极。研究发现，芳香族醌类分子修饰的碳基材料，其循环伏安曲线的峰形和峰位差具有特殊的特征，即峰位差非常小，且基本上不随扫描速率而变化，此外，它们的循环伏安曲线中响应电流与扫描速率呈现出线性关系，表明该类有机分子电极在电化学储能方面具有较高的应用价值。成功制备了10余种非共价功能化石墨烯为主体的有机分子电极体系（例如，茜素非共价功能化石墨烯水凝胶、有机分子功能化MOFs衍生的氮掺杂多孔碳、咖啡酸非共价修饰的多孔石墨烯水凝胶复合材料、（杂）芳香族有机分子非共价功能化石墨烯基材料、萘醌衍生物非共价修饰石墨烯纳米片、氧化还原活性有机分子-大黄素修饰石墨烯等），并通过合理匹配组成多种对称或非对称二电极储能体系，全面研究了它们的储能性能，尤其清晰地描绘出二电极体系中有机分子电极反应的相互适应或耦合匹配。从某种意义上讲，这是基金项目研究对该领域相关科学问题方面的理论贡献。此外，制作的器件型超级电容器，单器件可以点亮60个并联LED。在项目研究执行期间，我们在国内外学术期（J. Mater. Chem. A (4篇), Journal of Power Sources (2篇)、 J. Phys. Chem. C (1篇)、Electrochimica Acta (3篇)、 Journal of Colloid and Interface Science (1篇)、International Journal of Hydrogen Energy(1篇)、Dalton Transactions(1篇) 、Journal of Alloys and Compounds (4篇),等）发表学术论文32篇，其中SCI期刊源论文32篇，1区论文7篇，2区论文10篇。申请国家发明专利10项，授权6项。此外，在项目执行期间，共培养了12名硕士研究生和3名博士研究生。