Engineering\nof High-Density Thin-Layer Graphite Foam-Based\nComposite Architectures with Superior Compressibility and Excellent\nElectromagnetic Interference Shielding Performance

Abstract

Three-dimensional\n(3D) graphene architectures with well-controlled\nstructure and excellent physiochemical properties have attracted considerable\ninterest due to their potential applications in flexible electronic\ndevices. However, the majority of the existing 3D graphene still encounters\nseveral drawbacks such as brittleness, non-uniform building units,\nand limited scale (millimeter or even micrometer), which severely\nlimits its practical applications. Herein, we demonstrate a new scalable\ntechnique for the preparation of thin-layer graphite foam (GF) with\ncontrollable densities (27.2–69.2 mg cm^–3) by carbonization of polyacrylonitrile using a template-directed\nthermal annealing approach. By integrating the GF with poly­(dimethylsiloxane)\n(PDMS), macroscopic porous GF@PDMS with variable thin-layer GF contents\nranging from 15.9 to 31.7% was further fabricated. Owing to the robust\ninterconnected porous network of the GF and the synergistic effect\nbetween GF and PDMS, GF@PDMS with a 15.9% thin-layer GF content exhibited\nan impressive 254% increase in compressive strength over the bare\nGF. In addition, such 15.9% GF@PDMS can totally recover after the\nfirst compression cycle at a 95% strain and maintain ∼88% recovery\neven after 1000 compression cycles at an 80% strain, demonstrating\nits superior compressibility. Moreover, all of the as-prepared GF@PDMS\nsamples possessed high electrical conductivity (up to 34.3 S m^–1), relatively low thermal conductivity (0.062–0.076\nW m^–1 K^–1), and excellent electromagnetic\ninterference shielding effectiveness (up to 36.1 dB) over a broad\nfrequency range of 8.2–18 GHz, indicating their great potential\nas promising candidates for high-performance electromagnetic wave\nabsorption in flexible electronic devices.