▎ 摘　　要

With the rapid development of microwave technologies, electromagnetic pollution and stealth have become important problems to be solved. Although great efforts have been made in recent years, it is still a great challenge to achieve strong and broadband absorption combined with thermal and mechanical functionalities. Herein, a multi-functional design toward three-dimensional graphene foams (GFs) is provided. These foams are prepared to have large sizes by simple freezing and air-drying of a structure-integrated graphene oxide (GO) hydrogel, and polydimethylsiloxane (PDMS) is introduced to reinforce the GO framework. The remarkable finding is that the GF/PDMS composite possesses strong broad band absorption (reflection loss < -10 dB) over the entire frequency range of radar microwaves (2-18 GHz). This is attributed to the synergistic effects of dielectric loss of the GO material itself and the multi-layer attenuation brought by the porous foam structure. Experimental results also show that the light foams have very low thermal conductivity of 0.03-0.13 W m(-1) k(-1) and mechanical flexibility for compression, extension, and torsion. Therefore, this study provides a new strategy for large-scale production of multifunctional microwave absorbing foam materials for applications in both civil and military fields.