石墨烯/氮掺杂多孔碳复合电极膜的制备与电驱动性质研究

Compared with the traditional ionic polymer-metal composite electric actuators, carbon electrode based actuators overcomed the shortcomings of noble metal electrode, including its poor flexibility and easily to be broken upon swelling, and thus the cycling stability was improved. As a result, they has wide applications in intelligent robot, microcomputer operating system and many other fields. Among the reported carbon materials, graphene is expected to be good electrode materials for actuators with excellent performance due to its high specific surface area and high electron injection elongation. However, up to now, for most of the prepared graphene materials, the restacking of graphene layer happened during the preparation process which was caused by Vander Waals force between them and will lead to the decrease of specific surface area and pore sizes in graphene and finally lead to the decrease of the specific capacity. This will lead to small actuation displacement. Considering the above problems, this project aims to prepare graphene/nitrogen-doped porous carbon composite films as electrode for actuators. Firstly, the nitrogen doped carbon layer on the surface of graphene could avoid the restacking of graphene layers and increase the electric double layer capacitance; Secondly, the controllable hierarchical and porous structure of nitrogen doped carbon layer itself could further improve the electric double layer capacitance of the electrode materials; finally, the doped nitrogen in polyaniline based carbon materials could increase the pseudo capacitance of the electrode material. Thus, the high frequency response and stability of graphene electrode based actuators may be improved, which could lay the foundations for their practical application.

和传统离子型聚合物-金属复合电驱动器件相比，以碳基材料为电极的驱动器件克服了贵金属电极柔韧性差，溶胀时易发生断裂的缺点，大大提高了响应的循环稳定性，因此在智能机器人，人工助力系统和微机电操作等领域有着优异的应用前景。在已经报道的碳材料中，石墨烯由于具有较高的理论比表面积和量子伸长率，有望成为性能优异的驱动电极材料。然而目前所使用的大部分石墨烯基材料在制备过程中，其表面受范德华力影响而层层紧密堆叠，导致比表面积和多孔孔径减小，比电容较低，不利于大驱动位移的获得。针对这种现象，本项目拟制备石墨烯/氮掺杂多孔碳复合电极膜，首先，利用石墨烯表面的氮掺杂碳层避免石墨烯的堆叠，提高电双层电容；其次，利用氮掺杂碳层本身可控的分级与多孔结构进一步提高电极材料的电双层电容，最后，利用聚苯胺基碳材料中的掺杂氮提高电极材料的赝电容，从而有效地提高石墨烯基驱动器件的高频响应行为和稳定性，为其实际应用奠定基础。

二维碳基电极材料的多孔结构和化学组成是影响其储能和驱动性质的关键因素。对电极材料孔径结构的调控和元素掺杂状态的研究有利于进一步提高其比电容，从而提升电驱动性质。本项目以石墨烯和含氮聚合物为原料，通过多种结构诱导方法，实现孔径可控的二维氮掺杂碳基电极材料的制备，通过对多孔结构和元素掺杂含量与状态的研究，揭示了这两者与电极材料储能与驱动性质之间的关系。首先，我们利用碳纳米管与离子液体作为结构导向剂，利用这两者与石墨烯/聚苯胺复合物之间的相互作用力，成功制备了具有褶皱结构的石墨烯/聚苯胺基电极材料。由于产物电极膜具有丰富的多孔结构，因此表现出增强的储能和驱动性质。此外，我们使用双聚合物模板法，通过在制备过程中引入离子液体作为造孔剂，成功制得了具有多孔结构的碳片材料，产物同样具有较高的比电容，有望在驱动领域获得进一步应用。我们还研究了聚合物配比，离子液体的用量等参数对产物形貌和电容性质的影响，初步确立了电极材料微观结构与其电容之间的关系。由于氧化物阵列多孔结构的可控性比较强，我们还用阵列法尝试在二维碳材料表面生长氧化镍阵列，通过阵列多孔结构的控制实现储能驱动性质的提高，并阐述了相关理论，为高驱动活性电极材料的制备奠定了理论基础和技术基础。