High-efficiency electromagnetic shielding of three-dimensional laminated Wood/Cu/Ni composites

Construction of ideal dissipation path for layered electromagnetic shielding materials (EMSM) is promising but challenging. Herein, high-efficiency EMSM of three-dimensional hydrophobic wood/Cu/Ni laminated composites have been constructed to achieve laminated composites with high electromagnetic shielding efficiency and low reflection. The electromagnetic gradient structures are obtained via different Cu and Ni deposition times, where the slightly magnetic top Ni coatings serves as electromagnetic (EM) absorption layer and the highly conductive Cu coatings as reflection layer. The hierarchical porous wood structure could extend the EM dissipation path and dissipate EM by multiple reflections. Therefore, the laminated structure exhibits an excellent EM shielding efficiency (average 91.6 dB) at only 0.45 mm thickness between 8.2 GHz and 12.4 GHz in frequency. In addition, the contact angle of laminated composites was 117.8° and the Joule heating was nearly to 0, which broaden their application scenarios in practice. Furthermore, the multilayer Cu/Ni wood-based composites with sandwich-structured can be used as EM shielding gaskets and effectively block wireless power transmission and high frequency EM signal, which shows a prosperous application prospect in defense industry and aerospace.