Shape-memory polyimide/MXene/AgNWs networks for robust and reusable EMI shielding in harsh environments

Designing flexible electromagnetic interference (EMI) shielding materials that transition from static shielding to dynamic adaptability remains a significant challenge in the development of next-generation electronic protection. In this study, we fabricated a reusable flexible polyimide (PI)/MXene/silver nanowires (AgNWs) (PMA) EMI shielding composite film by assembling MXene and AgNWs onto a shape-memory PI matrix using a vacuum-assisted filtration technique. When the ratio of MXene to AgNWs was 2:1, the composite film exhibited a maximum electrical conductivity of 132 S/cm and an EMI shielding effectiveness of 60.68 dB in the X-band (8.2-12.4 GHz). After further optimizing the material structure, the gradient-structured PMA composite film (G-PM₂A₁) achieved a shielding effectiveness of 67.85 dB. The shielding performance remained essentially unchanged under harsh conditions, including ultrasonic cleaning, acid corrosion, high temperature (250 °C), and low temperature (−196 °C). Owing to the intrinsic shape-memory properties of polyimide, the film could recover its original structure after repeated deformation-heating cycles, maintaining an EMI shielding effectiveness above 60 dB. Moreover, the composite film exhibited excellent thermal stability, mechanical strength, and flame retardancy. Its lightweight, flexibility, and environmental stability indicate potential for localized EMI shielding applications relevant to electric vehicle battery systems, where lightweight, flexible, and environmentally robust shielding layers are required.