Cross-Dimensional Percolation and Metastructure-Assisted Highly Efficient Electromagnetic Interference Shielding...

Increasing electromagnetic interference (EMI) issues make shielding materials urgent in need. However, designing a thin/lightweight material with high shielding effectiveness (SE over 100 dB) by facile and scalable technologies with high production accuracy is still challenging. Herein, excellent shielding composite films are successfully prepared through sequential scalable positive pressure filtration, accurate inkjet printing, and facile transferring. From mass ratio optimization of 1D silver nanowires to 2D MXene, a skeleton with maximum inner free space and fast electron and phonon transport channels through cross-dimensional percolation is produced for internal multiple reflection absorption. To further increase EMI SE, graphene-based mesh metamaterials are theoretically calculated and accurately printed with controlled conductivity for impedance matching as the top layer. Facile inkjet printing succeeds in balancing print accuracy and conductivity control by advanced ink formulation. Finally, under multiple attenuation mechanisms verified through complex permittivity analysis in both frequency domain and real space (conductive loss, dipole polarization, and various interfacial polarizations), EMI SE of 102.31 dB in X-band is achieved. Integrating different attenuation technologies in a single material system of multidimensions inspires further designing shielding materials with increasingly strict requirements like multiband compatibility with special frequency enhancement.