Bilayer metal-organic frameworks/MXene/nanocellulose paper with electromagnetic double loss for absorption-dominated electromagnetic interference shielding

Abstract

MXene has been considered an advanced electromagnetic interference (EMI) material nowadays. However, the dense MXene films result in reflection-dominated electromagnetic shielding properties. The conjugation of magnetic metal–organic frameworks (MOFs) and conductive MXene is an attractive strategy for constructing absorption-dominated EMI shielding materials. Herein, we demonstrate the carbonized zeolitic imidazolate frameworks/MXene/nanocellulose (CZMN) paper prepared by a two-step vacuum-assisted filtration (TVAF) method, which leads to the formation of bilayer structure (Lower layer as highly magnetic adsorption layer and upper layer as highly conductive reflection layer). The CZMN paper shows excellent conductivity (∼29800 S·m−1), good magnetism (13 emu·g−1), and high EMI shielding effectiveness (SE) up to 62.4 dB at 8.2 GHz with absorption-dominated EMI shielding (SEA/SET up to 75%). More importantly, the effect of bilayer structure on the absorption and reflection of the electromagnetic waves are proved by experimental results. In addition, the total electromagnetic shielding performance of the prepared bilayer CZMN paper can be improved with the increase of the conductive layer content. At the same time, the absorption ratio can remain relatively stable. These features make the prepared bilayer CZMN paper a promising candidate for advanced equipment electromagnetic protection, military technology, and stealth materials.