Aramid nanofiber/liquid metal/Gd2O3 flexible films with magnetic-conductive interfaces for electromagnetic interference shielding and Joule heating

Abstract

The increasingly complex electromagnetic environments necessitate advanced electromagnetic interference (EMI) shielding materials with flexibility, high shielding efficiency, lightweight, and multifunctionality. Here, we present a mechanically robust and flexible aramid nanofiber/liquid metal/Gd₂O₃ (ALG) composite film engineered via vacuum-assisted filtration and mechanical pressing. By integrating liquid metal (LM) with high conductivity and rare-earth Gd₂O₃ nanoparticles to induce magneto-dielectric synergy, the optimized ALG film achieves exceptional electrical conductivity (1075.0 S/cm) and EMI shielding effectiveness (SE) of 74.3 dB at a minimal thickness of 68 μm, alongside a specific SE (SSE) of 1092.6 dB mm⁻¹. The unique combination of the conductive pathways of LM, the magnetic loss of Gd₂O₃, and the mechanical reinforcement of aramid nanofibers enables balanced dielectric-magnetic energy dissipation while maintaining ultra-low density and flexibility. To unravel the underlying shielding mechanism, frequency-domain simulations were performed using the High-Frequency Structure Simulator (HFSS), providing quantitative insights into the electromagnetic wave dissipation pathways within the composite. Furthermore, the film exhibits rapid Joule heating, highlighting its dual functionality for EMI shielding and thermal management. This work advances the development of multifunctional shielding materials for next-generation wearable electronics, aerospace systems, and defense technologies.