石墨烯/聚乙烯醇“互啮”型交替层状材料的构筑及其电容性能的研究

Capacitors are important storge component in electronic equipment. It is a problem attacting wide attention that how to obtain capacitors with high energy storge density, small volume and light quanlity. Enlarging electrode area under same volum is one of main appoaches in solving this problem. Since graphenes has excellent electrical conductivity and a flake shape with high aspect ratio while polymers are insolent, the alternate-layered structure of graphene and ploymer could form a microcapacitor. The propose of this project is preparing a novel film capacitor consisting with intermeshing alternating layers of graphene and polymer through spinning coating & self-assembly technology. By controlling the dispersion of the graphene sheets in polymer matrix, a shunt capacitance will be built. This film capacitor,having similar structure with that of Multi-Layer Ceramic Capacitor, might have high energy density, low loss and good flexibility. The effect of spin-coating factors and self-assembly factors on microstructure of the composite will be studied and the mechanism will be analyzed. On this basis, an effective method in controlling micro-morphologies will be constructed. Then, alternated-layered composite with different microstructures (such as different polymer layer, different graphene layer, different interface layer and different number of layers) will be built and the relationships between their microstructure and capacitive performance will be deeply studied and compared. The research work of this project may provide a new promising method and its scientific evidence to prepare a film capacitor with high capacity,low loss and good flexibility.

如何获得体积小，质量轻，储能密度高的大功率电容器是人们一直以来的追求。在同样体积下，尽可能的增加电极总表面积以提高储能密度是实现这一目标的主要手段之一。本研究拟采用旋涂-组装的方法制备与多层陶瓷电容器结构类似的石墨烯/聚乙烯醇"互啮"型交替层状材料，利用石墨烯层的高导电性和聚乙烯醇层的绝缘性构成若干微电容的并联，以获得具有高储能密度、低损耗，柔韧性好的薄膜电容。通过研究构筑过程中各种因素（如：溶液浓度、旋涂参数等）对材料结构、形态的影响规律及其作用机理，建立起形貌调控的有效手段；在此基础上，制备出具有不同微观结构的层状复合材料，深入研究其微观结构（如聚乙烯醇层结构、石墨烯层结构、界面层结构、组装层数等）对电容性能的影响规律及作用机理；探索设计、制备高储能密度、低损耗、柔韧性好的多层薄膜电容的新思路及其科学依据。这无论是从基础理论研究角度还是对推动新材料的研究与应用开发都具有重要的意义。

如何获得体积小，质量轻，储能密度高的大功率电容器是人们一直以来的追求。高介电常数、低介电损耗、柔韧性好的电介质材料是实现这一目标的主要手段之一。然而怎样同时实现高介电常数与低介电损耗是介电材料研究领域的一大难题。针对这一问题，本项目首先采用非共价改性的方式实现了石墨烯的表面修饰。研究结果表明：基于π-π或π-离子间相互作用均可实现对石墨烯的有效改性。在保留石墨烯优异导电性能的基础上可解决石墨烯易团聚，与基体聚合物界面作用不好的局限。所获得的改性石墨烯具有较高的导电性和良好的分散能力。然后，我们尝试采用不同的方式（溶液浇铸-层叠热压法，层层旋涂及层层浸涂法）构筑石墨烯/聚合物的交替层状结构。并研究了构筑过程中各种因素对材料结构、形态的影响规律及其作用机理。研究结果表明，溶液浇铸-层叠热压法难以达到真正微观尺度上的控制。在石墨烯含量增大时易于形成局部的导电搭接网络。层层旋涂法则可以得到规整度高的交替层状聚合物薄膜。且其形貌可控。由此探索出一个微观尺度上结构可控的石墨烯/聚合物层状复合材料的构筑方法；在上述研究工作的基础上，本项目通过制备不同微观结构的石墨烯/聚合物复合材料并研究其结构与介电性能之间的关系，阐明了其微观结构对介电性能的影响规律及作用机理，探索出设计、制备高介电常数、低介电损耗，柔韧性好的多层薄膜的新思路及其科学依据。这无论是从基础理论研究角度还是对推动新材料的研究与应用开发都具有重要的意义。