煤基功能碳材料的合成及储能应用

Synthesis of coal-based functional carbon materials and its application in energy storage

煤及其热加工转化的衍生品煤沥青等是重要的化工资源,基于分子化学工程的技术方法和多维碳材料工程的新理念,发展煤基功能碳材料是实现煤炭资源清洁高效高值利用的有效途径。煤炭及煤沥青在分子层面呈现稠环芳烃特性,可通过物理外场(微波、等离子体等)强化作用,利用分子化学裁剪、杂化改性、界面组装等技术手段,实现零维、一维、二维和三维煤基功能碳材料的可控合成,将推动煤基功能碳材料的储能应用。介绍了煤及其热加工转化衍生品的来源、种类及理化性质,系统总结了数种煤基功能碳材料如碳点、炭纤维、碳纳米管、石墨烯、炭纳米片、多孔炭、炭气凝胶、泡沫炭等的制备方法及优缺点;重点介绍了硬炭、软炭、多孔炭、杂原子掺杂炭等煤基功能碳材料的储能应用,突出了碳层取向调控、杂原子掺杂、限域空间构筑等技术策略在提升碳材料离子存储性能方面的重要作用;介绍了煤基功能碳材料与过渡金属或过渡金属化合物有机耦合制备复合材料的方法,诠释了煤基碳源之性质与高容量且体积变化明显的碳电极材料之结构性能间的本征构效关系;讨论了煤基功能碳材料面临的可控度低、前驱体分子结构演变复杂、合成方法优化等问题。基于分子化学工程理念及过程强化技术的发展,讨论了煤基功能碳材料的未来发展方向。

Coal and its derivatives from the thermal conversion processes such as coke production are important chemical resources.The production of coal-based functional carbon materials(CFCMs)enabled by the theory and techniques of the molecular chemical engineering and the multi-dimensional carbon engineering,is an effective way to realize an efficient and clean utilization of coal resources.Coal and coal tar pitch feature the characteristics of polycyclic aromatic hydrocarbons at the molecular level.The controllable synthesis of zero-dimensional,one-dimensional,two-dimensional,and three-dimensional CFCMs can be enhanced by the physical fields such as microwave and plasma via molecular chemical cutting,hybridization,and interface assembly,promoting the applications of the CFCMs in energy storage fields.Firstly,the sources, types, and physicochemical properties of coal and its derivatives from the thermal conversion processes are intro-duced in detail in terms of the synthesis of CFCMs. Then, the preparation methods, advantages, and disadvantages of vari-ous CFCMs such as carbon dots, carbon fibers, carbon nanotubes, graphene, carbon nanosheets, porous carbon, carbon aerogels, and carbon foam are summarized systematically. After that, the applications of CFCMs in energy storage are dis-cussed in terms of hard carbon, soft carbon, porous carbon, and heteroatom doped carbon, and the impacts of carbon layer orientation regulation, heteroatom doping, and confined space construction on the ion storage capability are highlighted. Next, the methods of making hybrids by combining coal-based functional carbon materials with transition metals are sum-marized, and the structural regulation effect of coal-based carbon sources on the electrode materials with high capacity but significant volume change is discussed. The key issues related to the CFCMs in terms of controlled fabrication, the tuning and evolution of molecular structure and activity of the precursors, and the synthesis methods are addressed. Finally, the perspective and future directions of the CFCMs are outlined, which will be pushed forward by the theory and techniques originated from the molecular chemical engineering and the enhanced mass and heat transfer strategies.