氧化石墨烯诱导纳米薄层多孔炭的定向组装及其结构与电容性能调控

Carbon-based supercapacitor is considered as an efficient device for energy storage and conversion. The porous structure, electrical conductivity, tap density and surface chemical properties of carbon materials have a great influence on their electrochemical performance in supercapacitors. The project aims to synthesize graphene-directed porous carbon nanosheets, which is based on the solution self-assembly and polymerization of phenols and formaldehyde around graphene oxides (GOs). Through control of the interactions between the monomers and the GOs with the aid of amino acids, the amount of the graphene and the thickness of porous carbon nanosheets can be precisely adjusted. The porous structure, surface chemical property and local microcrystalline structure of the graphene-directed porous carbons may be tuned by the uses of ionic liquids, porogens and physical activation method. Hence, we can synthesize sheet-like porous carbon materials with high electrical conductivity, appropriate density and developed pore system allowing easy access for electrolyte ions. The capacitance performance, cyclic voltammetry and galvanostatic charge/discharge features will be characterized. Particularly, the electrochemical impedance spectroscopy (EIS) will be employed as a key technique to study the charge transfer and ion diffusion behavior between electrodes and solution interfaces. The project will elucidate the mechnism of GO directed assembly of carbon precusors and the influence of structure and surface chemistry of the carbons on their electrochemical performance. This will provide a basis for fabrication of supercapacitors with high energy density, high power density and excellent cycling performance.

炭基超级电容器是一种高效的能量转换和储存设备。炭电极材料的孔隙结构、电导率、振实密度及表面化学是影响其电容行为的关键因素。本项目拟以氧化石墨烯为结构导向剂，采用溶液合成方法诱导酚醛的定向组装，制备内含石墨烯的纳米薄层多孔炭材料。通过调变酚醛与氧化石墨烯之间的相互作用，分别实现对片层结构中石墨烯含量和多孔炭层厚度的准确控制；通过引入功能离子液、造孔剂或结合物理活化,协同调控多孔炭层的孔隙尺寸和局域微晶结构，适度修饰多孔炭层的表面化学，获得电导率高、孔隙发达并且可被电解液离子充分利用、密度适中的多孔炭电极材料的制备方法，并系统研究材料的电容性能，重点采用交流阻抗谱研究电极与溶液界面的电荷转移和离子扩散。项目将阐明氧化石墨烯导向聚合物组装及构筑机制，揭示片层多孔炭材料结构参数及表面化学的调控及其对超级电容器能量储存性能的影响规律，为构筑高功率密度、高能量密度、长循环寿命的超级电容器提供科学依据。

炭电极材料的孔隙结构、电导率及表面化学是影响炭基超级电容器电容行为的关键因素。本项目以氧化石墨烯为结构导向剂，通过引入功能离子液，采用溶液合成方法诱导酚醛的定向组装，制备了内含石墨烯的纳米薄层多孔炭材料。通过调变酚醛与氧化石墨烯之间的相互作用，可调控多孔炭层厚度(5-140 nm)。应用于超级电容器电极材料，0.5A/g下比容量达213 F/g，且10 A/g下容量保持率为75.1% (160 F/g)，展现出优异的比电容特性和倍率性能。循环35000次容量保率为99.3% 。提出利用配位作用，实现动态造孔，可调节多孔炭层的孔隙尺寸。利用温控相变概念，合成了有机片层结构导向剂，制备出孔道通透的纳米炭片，丰富了炭片的制备方法，优化了孔隙结构，理解了模板与聚合物组装及构筑机制，揭示片层多孔炭材料结构参数及表面化学的调控及其对超级电容器能量储存性能的影响规律。 研究成果在国际期刊发表16篇论文，影响因子大于8的论文7篇，申请专利2项，授权1项；培养毕业博士研究生2名，另有2名在读，培养毕业硕士研究生9名，参加国际会议2次，国内电化学相关会议4次，口头报告3次。