Synthesis of high-quality vertical graphene nanowalls on metal foams and their applications in EMI shielding

Due to the development of high-frequency electronic devices, electromagnetic pollution has attracted global attention. Electromagnetic interference (EMI) shielding materials with low thickness, improved EMI shielding performance and lightweight are highly required for protecting the devices. Metal foams (MFs) and carbon-related materials have been successfully applied in EMI shielding. Herein, by utilizing the plasma-enhanced chemical vapor deposition (PECVD) method, high-quality vertical graphene nanowalls (VGNs) were prepared on Cu foam (CF) and Ni foam (NF) substrates. The combination of porous VGNs and MFs significantly improved their electrical conductivity, thus their EMI shielding performance was enhanced. The electrical conductivity of the VGNs/CF films could reach 4.81 × 106 S·m-1, increased by 15.3 % compared with the pristine CF films. At a frequency range of 8.2–12.4 GHz, the EMI shielding effectiveness values of VGNs/CF films with a thickness of ∼ 120 µm could reach 81.7 dB, increased by 25.9% compared with the pristine CF films. The VGNs/MF composite films with preferable EMI shielding effectiveness provide a new possibility for developing high-performance EMI shielding materials.