Anisotropic microcellular epoxy/rGO-SCF aerogel foam with excellent compressibility and superior electromagnetic interference shielding performance

Abstract

Carbon aerogel shows great potential in electromagnetic interference shielding (EMI) application and is generally strengthened by epoxy impregnation for harsh working environment. However, it is still challenging to simultaneously achieve high mechanical robustness and EMI performance, especially taking low-cost and light-weight feature into account. In this work, a “gelation-press drying-impregnation & micro-foaming” method was systematically reported to target microcellular epoxy foam containing hybrid reduced graphene oxide (rGO)/short-carbon-fiber (SCF) aerogel. Herein, aerogel morphology was transformed from isotropic honey-comb structure into anisotropic corrugated structure by controllable press air-drying. A further supercritical carbon dioxide (scCO2) foaming process was implemented for density reduction. Moreover, the anisotropic microcellular epoxy(m-EP)/rGO-SCF foam (D = ∼0.48 μm, Nf = 5.02 × 1012 cell/cm3) shows low density (1.14 g/cm3), high electrical conductivity (2365.0 S/m), enhanced compressibility (σb = 243.0 MPa, εb = ∼45%) and outstanding EMI shielding effectiveness (95.5 dB) with a low thickness (2.0 mm) within X band (8.2–12.4 GHz). Therefore, our work provides a universal step-by-step and industrial-friendly approach to fabricate light-weight carbon-aerogel-based foams with anisotropic carbon structure and outstanding EMI performance.