具有发达离子扩散通道的石墨烯基复合薄膜及高体积能量密度柔性超级电容器的研究

To solve the problem of low volumetric energy density for flexible energy storage device, this project makes use of hetero-atom modified porous graphene and carbon nanotubes-metal oxide as basic unit, preparing flexible film electrode materials by 3D space assembly with the integration of 3D ion diffusion channels, integrated conductive network, surface modification and high pseudocapacitance. The carbon nanotubes-metal oxide can construct ion diffusion channel between the layers in the dense graphene. Simultaneously, the design of the pore on the graphene surface ensures that the fast diffusion of electrolyte ions on the direction of perpendicular to the graphene sheets, resulting the electrode material to form developed 3D ion diffusion channels. This research focuses on the effect of pore structure and surface modification on the conductivity, wettability and electrochemical properties of the composites. We will also explore the principle of the matched positive/negative electrodes with loading different metal oxide in different voltage window for asymmetric supercapacitors, as well as its effect on the electrochemical performance. The research of this project will help to realize controllable regulation of structure and performance for flexible electrode material, and obtain the asymmetric flexible supercapacitors with high volumetric energy/power density, long cycle life and good rate capability, which may provide theory basis and feasible measures for promoting future application of flexible energy storage devices.

针对目前柔性储能器件体积能量密度低的问题，本项目拟采用杂原子修饰的多孔石墨烯和碳纳米管-金属氧化物为基础单元，通过三维空间组装的方式制备具有发达离子扩散通道、整体导电网络、表面修饰、高赝电容等功能集成的柔性薄膜材料。碳纳米管-金属氧化物可在致密体石墨烯的层间搭建离子扩散通道；同时石墨烯片层上孔道的设计又确保了电解液离子在垂直方向上的快速扩散。重点研究材料的孔结构和表面修饰对复合材料的导电性、浸润性、电化学特性的影响；探寻负载不同金属氧化物的正/负电极材料在不同电压窗内的匹配规律，组装非对称柔性超级电容器并研究其电化学性能。通过本项目的研究，实现柔性电极材料结构与性能的可控调节，并获得具有高体积能量/功率密度、长循环寿命、高倍率特性的非对称柔性超级电容器，为推动柔性储能器件的应用提供理论基础和实验依据。

在国家自然科学青年基金的资助下，本项目执行人利用多种方法极大地提高了柔性储能器件的体积能量密度。本项目分别以杂原子修饰的多孔石墨烯和碳纳米管-金属氧化物为基础单元，通过三维空间组装的方式实现了具有发达离子扩散通道、整体导电网络、表面修饰、高赝电容等功能集成的柔性薄膜电极材料的可控制备。研究了所制备柔性电极材料的密度、孔结构及电化学性能之间的平衡关系，并通过材料表面修饰提高了复合膜材料的整体导电性及浸润性，极大地提高了电极材料的整体电化学特性。基于高性能电极材料实现了柔性电极材料结构与性能的可控调节，并通过非对称柔性超级电容器组装获得了具有高体积能量/功率密度、长循环寿命、高倍率特性的非对称柔性超级电容器。我们提出了一种以离子通道构筑基元、导电基元、赝电容基元为功能基元制备柔性电极材料的制备方法；揭示了不同赝电容电极材料（金属氧化物）基元不同电压窗内的匹配规律；阐明了高性能非对称柔性超级电容器的组装方法。因此，本项目工作的顺利进行为推动柔性储能器件的应用提供了重要的理论基础和实验依据。