Enhanced electromagnetic interference shielding, thermal management, and Joule heating performance in polymer composite film by incorporating hybrid graphene-silver nanowire networks

Abstract

As consumer electronics advance towards lightweight and high-integration designs, the demand for flexible, high-performance electromagnetic interference (EMI) shielding and thermal conductive materials has increased. Incorporating functional fillers into polymer matrices is an effective approach to address these needs. However, achieving a lightweight, flexible, ultra-thin and high-performance thermal conductive and electromagnetic shielding films using a simple and scalable manufacturing process remains a challenge. To address this critical challenge, we designed a flexible and ultra-thin film (50 μm) by integrating one-dimensional silver nanowires (AgNWs) and two-dimensional graphene nanosheets (GNs) into a thermoplastic polyurethane (TPU) matrix using a scalable blade-coating technique. The combination of AgNWs and GNs forms a synergistic hybrid conductive network, where AgNWs act as bridges connecting GNs, ensuring continuous conductive pathways. During the blade-coating process, the GNs align parallel to each other, creating a dense conductive structure that imparts high electrical conductivity, thermal conductivity and exceptional electromagnetic shielding effectiveness (EMI SE) to the composite film. The resulting ultra-thin film exhibits an electrical conductivity of 303.12 mS/m, an outstanding in-plane thermal conductivity of 22.4 W/(m·K) and an ultra-high EMI SE of 57 dB at 10 GHz. The film achieves an exceptional specific shielding effectiveness per unit thickness of 6952 dB cm² g⁻¹, surpassing most of previously reported values. Furthermore, the composite film demonstrates excellent Joule heating performance (The saturated temperature reaches to 111.3 °C under a voltage of 2.0 V), showcasing its potential for thermal management and electro-thermal conversion. This work offers a simple yet effective approach for the design of high-performance flexible conductive polymer composite films, offering multifunctional capabilities in EMI shielding, thermal management and Joule heating performance.