Construction of a photonic radiative cooling layer based on a 3D conductive network foam for efficient electromagnetic interference shielding and environmental thermal comfort

Abstract

The environment on which people depend for their survival is becoming increasingly complex and deteriorating due to increasing electromagnetic pollution and extreme hot weather. Therefore, composites with both electromagnetic interference (EMI) shielding and radiative cooling are clearly attractive for the protection of human health and the proper functioning of electronic equipment. In this work, we immersed electromagnetic polypyrrole (PPy)@Fe₃O₄ particles into melamine foam (MF)@PPy foam (MPPF) with a 3D conductive network structure and combined it with laminated silver aramid paper (AgP)/polydimethylsiloxane (PDMS)/Al₂O₃ (A₁PA₂) with high electrical conductivity and optical properties to prepare MPPF-A₁PA₂ composites with asymmetric structures. This composite has excellent impedance matching and electromagnetic wave attenuation capabilities, and with the cooperation of a reflective Ag layer, an absorption-based electromagnetic wave loss mechanism is realized, achieving a total shielding effectiveness (SE_T) of 65.0 dB and an absorption coefficient (A) of 0.79. In addition, the high solar reflectivity (88.0%) and high mid-infrared emissivity (95%) of the composites can satisfy the cooling effect achieved on different substrates without external energy input and provide an average subambient radiative cooling effect of 8.7 °C at a solar radiation intensity of 713 W m⁻². Thus, this work provides new insights into the design of materials with both high absorptive shielding performance and radiative cooling performance.