Engineered Interpenetrating MXene Networks in Aramid Layered Films for Antioxidant and Broadband Electromagnetic Interference Shielding.

MXene-based layered films featuring a "brick-and-mortar" architecture show significant potential for electromagnetic interference (EMI) shielding applications; however, the insulating polymer "mortar" disrupts the connectivity of the MXene network, ultimately compromising both electrical conductivity and shielding effectiveness (SE). To address this limitation, this study introduces an innovative interpenetrating layered structure, comprising independent aramid nanofiber (ANF) layers and MXene layers, fabricated through a directional freeze-thaw intercalation-gel-film formation strategy. Unlike traditional homogeneous layered films, this unique layered structure features mutually embedded conductive and insulating layers, facilitating efficient electron transport, generating numerous heterogeneous interfaces for multiple reflections and scattering, and enhancing oxidation resistance. The interpenetrating ANF/MXene film exhibits exceptional electrical conductivity (5630.8 S/m) and EMI SE (43.3 dB) at ∼40 wt.% MXene loading, significantly outperforming the homogeneous ANF/MXene film (26.9 dB). Importantly, the interpenetrating ANF layers fully encapsulate the MXene layers, providing remarkable long-term stability with only a 10% decline in EMI performance after 80 days of aging. Furthermore, the interpenetrating ANF layers form a resilient mechanical framework, resulting in the A@M film boasting outstanding mechanical properties (tensile strength of 121.0 MPa, fracture strain of 13%). Consequently, this work presents a novel design and approach for fabricating high-performance MXene-based layered EMI shielding films.