High-performance electromagnetic shielding materials are highly desired due to the radiation and interference problems of electronic equipment. In this work, a flexible graphene/multi-walled carbon nanotubes (MWCNTs)/Polydimethylsiloxane (PDMS) electromagnetic shielding composite is fabricated with 3D graphene/MWCNTs foam as electrical conductive skeleton. The structure and composition evolution of foams are studied during the carbonization process from 1200 to 1600 ^oC and the graphitization of ultra-high temperature (2800 ^oC). With the removal of functional groups, the repair of defects enhances the ohmic loss while the polarization loss is reduced. An optimal electromagnetic interference shielding effectiveness(EMI SE)is found with an EMI SE of 54.43 dB at 1400 ^oC. Moreover, compared to pure PDMS, the thermal conductivity of the composites is increased by 193% and the compressive strength is improved from 1.40 MPa to 1.94 MPa. This contribution provides a guidance for designing high-performance carbon-based electromagnetic shielding materials.

由于电子设备的辐射和干扰问题，非常需要高性能的电磁屏蔽材料。在这项工作中，以3D石墨烯/ MWCNTs泡沫为导电骨架，制备了柔性石墨烯/多壁碳纳米管（MWCNTs）/聚二甲基硅氧烷（PDMS）电磁屏蔽复合材料。研究了在1200至1600 ^o C的碳化过程以及超高温（2800 ^o C）的石墨化过程中泡沫的结构和组成演变。通过去除官能团，缺陷的修复增强了欧姆损耗，同时减少了极化损耗。最佳电磁干扰屏蔽效果（EMI SE）在1400 ^o时的SE为54.43 dB此外，与纯PDMS相比，复合材料的导热系数提高了193％，压缩强度从1.40 MPa提高到1.94 MPa。该贡献为设计高性能碳基电磁屏蔽材料提供了指导。