钡铁氧体/石墨烯/MXenes三元全片层复合结构的制备及吸波性能研究

Low density, wide absorption band and strong absorption are highly demanded for modern excellent microwave absorbing materials. In view of this, we design a novel stacked structure with lamellar graphene/barium ferrite/MXenes in this proposal. Modified by cationic/anionic surfactants, graphene and MXenes lamellas would be positively/negatively charged respectively, forming tight combination under the electrostatic interaction. After hydrothermal/solvothermal treatment, lamellar barium ferrite could be deposited on the surfaces of graphene/MXenes, forming a novel stacked structure of graphene/barium ferrite/MXenes. This ternary stacked structure is thoroughly constructed by two-dimensional lamellar materials and could have large surface dipole, high magnetic loss tangent angle and anisotropy, which are beneficial to the strong electromagnetic loss and the extension of the absorption band. Meanwhile, based on the good thermal conductivity and electric conductivity of MXenes, and the unique lamellar structures, a maze of electromagnetic wave could be realized, resulting in strong absorption of electromagnetic wave after multiple reflections and absorptions. In particular, for the composite, the electromagnetic parameters are adjustable, facilitating the fulfillment of impedance matching. In addition, the coating slurry has good flexibility, high mechanical strength and easy molding. In this project, we would dedicate to investigate the relationship between the new synthesis processing of ternary composite structure, the synergistic effects and interface effects and the reasons for the improvement of the electromagnetic properties, establish the relationship among microstructure, magnetic domain structure and electromagnetic performance of the composite, and reveal the mechanism of electromagnetic loss. Our research would provide much experimental and theoretical basis for the application extension of the microwave absorbing materials.

针对现代高性能吸波材料所需低密度、宽吸收带和强吸收等问题，本项目拟对石墨烯和MXenes片层采取阴阳离子表面活性剂修饰的方法，使其分别带上正负电荷，在静电相互作用下有效结合，经水热溶剂热处理后，负载上片状钡铁氧体，得到钡铁氧体/石墨烯/MXenes三元全片层复合结构。该复合结构全由片层组成，具有大偶极矩、高磁损耗正切角和各向异性等效场，利于实现强电磁损耗，宽吸收带。结合其独特的片层结构、MXenes优良的导电导热性能，构建电磁波迷宫，使得电磁波在片层间多次反射、吸收，实现强吸收。该复合结构电磁参数可调节，易于满足阻抗匹配。同时，其涂覆浆料柔性好，机械强度高，易于成型。本项目重点探索三元复合结构制备工艺、三元间协同效应及界面效应与电磁参数改善之联系，建立复合材料显微结构、铁氧体磁畴结构与宏观电磁性能间的构效关系，揭示该类体系的电磁损耗机理，为拓展其在吸波材料领域的应用提供实验基础和理论依。

设计并采用两步溶解热法制备了BaFe12O19 (BFO)薄片、二维石墨烯和Fe3O4纳米颗粒的复合材料。BFO薄片与二维石墨烯可以有效增强异质界面，有利于界面极化增强。引入反尖晶石Fe3O4作为第三相可以提高饱和磁化强度。由于BaFe12O19薄片和石墨烯界面之间的极化增强，RGO/BaFe12O19/Fe3O4的复合材料具有良好的微波吸收性能。在15.6 GHz厚度为1.8 mm时，最大反射损耗可达-46.04 dB，有效吸收带宽达到5.68 GHz(从11.60 GHz到17.28 GHz)。此外，我们报道了一种层间电子/离子双传输通道设计策略，基于一维导电细菌纤维素@聚吡咯在二维单层MXene片层间的均匀插层，同步构筑层间电子/离子双传输通道，有效缓解了二维单层MXene自组装薄膜由片层密堆积引起的层间离子传输受阻以及由插层物引起的层间电子传输受阻问题。为获得高性能的储能器件，我们还制备了Co3S4 纳米片。结合理论计算费米能级和电子态密度结果显示片层结构有利于促进了快速电子转移路径，为催化反应提供了高的活性位点。为实现高性能的OER和ORR催化活性，我们将碳材料与过渡金属化合物进行复合，作为空气电极催化材料，制备了平面叉指锌空气电池。累计发表SCI论文22篇，授权发明专利1项。