成果简介

二维石墨烯纳米片的自堆叠倾向与固有缺陷显著削弱了石墨烯薄膜的导电性与界面结构，从而限制了其电磁波吸收性能及电磁干扰（EMI）屏蔽效率。然而，通过合理优化导电网络结构与微介观界面以实现卓越的EMI屏蔽性能，仍是当前面临的重要挑战。本文，西南交通大学祁青、孟凡彬教授团队在《Carbon》期刊发表名为“Biomimetic dictyophora-inspired RGO/MXene aerogel films for synergistically enhanced EMI shielding and photothermal conversion performance”的论文，研究报道了一种具有仿生结构的氧化石墨烯/MXene气凝胶薄膜（RGMA），其界面采用仿拟Dictyophora的定向多孔分级结构，呈现交替搭接式构型。

该结构通过有机分子修饰的氧化石墨烯（RGO）与MXene纳米片交替自组装，经液氮冰模板处理及冷冻干燥工艺实现。表征结果证实了大尺寸RGO片与小尺寸MXene纳米片有序交替自组装，形成了界面搭接结构。七层RGMA薄膜（RGM3A-7）在2-18 GHz频率范围内实现了约35 dB的EMI屏蔽效能。此外，三层RGMA薄膜（RGM1A-3）展现出卓越的光热转换性能，响应时间<30秒，稳定温度达51.7℃。这种石墨烯基薄膜兼具优异的电磁干扰屏蔽与光热转换能力，彰显其在可穿戴抗干扰设备领域的巨大应用潜力。

图文导读

图1、Schematic diagram of the RGMA films preparation process.

图2. Cross-sectional SEM images of the prepared GMA films with varying numbers of alternating interface layers: (a–b) Low-resolution and high-resolution SEM images of the GM₀A-1 film, respectively. (c–d) SEM images of the GM₁A-3 film and its corresponding interfacial structure, respectively. (e) SEM image of the GM₂A-5 film. (f) SEM image of the GM₃A-7 film. (g–i) SEM images and corresponding EDS mappings of Ti element for the GM₁A-3 film, GM₂A-5 film, GM₃A-7 film, respectively (Inset images are the corresponding schematic diagrams of the alternating layers in the aerogel films.).

图3. Cross-sectional SEM images of the RGMA films: (a) SEM image of the RGM₀A-1 film. (b) SEM image of the pure MXene film. (c) SEM image of the interface structure of the RGM₁A-3 film. (d) SEM image of the RGM₁A-3 film. (e) SEM image of the RGM₂A-5 film. (f) SEM image of the RGM₃A-7 film. (g–i) XRD patterns and Raman spectra of the aerogel films, respectively.

图4. (a) FTIR spectra of the composite aerogel films. (b) XPS survey spectra of the MXene film and RGM₁A-3 film. (c) C 1s, (d)Ti 2p, (e) O 1s, and (f) N 1s XPS spectra of the RGM₁A-3 film.

图5. The EMI shielding performance of the composite aerogel films in the frequency range of 2–18 GHz: (a) The total EMI shielding efficiencies (EMI SE_T). (b) Microwave adsorption (SE_A). (c) Microwave reflection (SE_R). (d) The effective absorption coefficient. (e) The reflection coefficient (R), absorption coefficient (A), and transmission coefficient (T) of RGM₃A-7 film. (f) Comparison of SE_T values of the RGMA film with other EMI shielding porous carbon-based materials with different thicknesses (the literature references corresponding to the compared materials in the figure are listed in Table S1). (g) Schematic illustration of the EMI shielding mechanism in composite aerogel film.

图6. The infrared thermal images of the (a) RGM₀A-1, (b) RGM₁A-3, (c) RGM₂A-5, and (d) RGM₃A-7 films at different light exposure time during the photothermal conversion process. (e) The corresponding time-temperature curves of the films during the photothermal conversion process.

小结

综上所述，本研究报道了一种具有仿生Dictyophora多孔分级交替搭接结构的RGMA薄膜，该薄膜兼具电磁屏蔽性能与快速光热响应特性。通过交替自组装、液氮辅助冰模板冷冻、冷冻干燥及后续HI蒸汽还原的序列工艺，成功合成了这种复合气凝胶薄膜。通过氧化石墨烯与MXene纳米片构筑的内部定向排列开孔结构及交替界面，可促进电磁波的内部多重反射与吸收，从而形成广泛的电磁波能量衰减路径。同时，高电导率与偶极极化效应的协同作用进一步增强电磁波耗散，提升整体电磁屏蔽性能。具体而言，RGM3A-7薄膜在2-18 GHz频段内，3.5毫米厚度下展现出约35 dB的卓越屏蔽效能。此外，RGM1A-3薄膜展现出优异的光热转换性能，具有快速光热响应和高温度稳定性。这种仿生多孔分级结构设计（灵感源自Dictyophora）使RGMA薄膜能够集成多种功能（电磁屏蔽与光热转换），彰显其满足高度集成多场景应用复杂需求的潜力。

文献：

https://doi.org/10.1016/j.carbon.2025.120788