Multifunctional Flexible Electromagnetic Interference Shielding Silver Nanowires/Cellulose Films with Excellent Thermal Management and Joule Heating Performances

Flexible electromagnetic interference (EMI) shielding materials with excellent thermal conductivities and Joule heating performances are of urgent demand in the communication industry, artificial intelligence, and wearable electronics. In this work, highly conductive silver nanowires (AgNWs) were prepared using the polyol method. Cellulose sheets were then prepared by dissolving natural cotton in a green and efficient NaOH/urea aqueous solution. Finally, multifunctional flexible EMI shielding AgNWs/cellulose films were fabricated based on vacuum-assisted filtration and hot-pressing. AgNWs are evenly embedded in the inner cellulose matrix and overlap with each other to form a 3D network. AgNWs/cellulose films, with a thickness of 44.5 μm, obtain the superior EMI shielding effectiveness of 101 dB, which is the highest value ever reported for shielding materials with the same thickness. In addition, AgNWs/cellulose films present excellent tensile strength (60.7 MPa) and tensile modulus (3.35 GPa), ultrahigh electrical conductivity (σ, 5571 S/cm), and excellent in-plane thermal conductivity coefficient (λ∥, 10.55 W/mK), which can effectively dissipate the heat accumulation. Interestingly, AgNWs/cellulose films also show outstanding Joule heating performances, good stability, and sensitive temperature response at driving voltages, absolutely safe for the human body. Therefore, our fabricated multifunctional flexible AgNWs/cellulose films have broad prospects in the fields of EMI shielding and protection of outdoor large-scale power transformers and wearable electronics.