Multifunctional WSCA /MXene Composite Paper for Electromagnetic Interference Shielding, Respiratory Monitoring, and Electro‐Optical‐Thermal Conversion

Abstract The widespread use of wearable electronic devices has raised concerns about the health risks of electromagnetic radiation, and the development of advanced composite materials that combine efficient electromagnetic shielding with physiological monitoring remains a challenge. In this paper, Water‐Soluble Cellulose Acetate (WSCA)/MXene composite paper (CM) with “brick mud” structure is prepared by vacuum‐assisted filtration using MXene as a conductive filler and WSCA as a dispersive enhancer with the ability to capture water molecules, which can realize efficient electromagnetic shielding (EMI) as well as breath monitoring. The nanopaper exhibits a high electromagnetic shielding value of 77.4 dB, an ultra‐high electrical conductivity of 16,817.4 S m ⁻¹ , and the ability to accurately monitor respiration before and after exercise. In addition, the material has a tensile strength of 89.6 MPa and efficient electrical/photothermal conversion. The nanopaper rapidly warms to 113.8 °C at 2 V and reaches 103.9 °C in 60 s under external light, enabling infrared stealth over a wide temperature range of 32–114 °C. CM papers overcome the technical limitations of traditional single‐function materials by virtue of a dual mechanism. It has important application value in the fields of personal electromagnetic protection, dynamic thermal management and intelligent medical sensing.