Hierarchically porous chitosan/MWCNT- derived Bimetallic Carbon aerogel for electromagnetic interference shielding

This study aims to develop an ultra-lightweight, high-performance electromagnetic (EM) wave-absorbing hierarchical porous bimetallic carbon aerogel by compositing chitosan with multi-walled carbon nanotubes (MWCNTs). This approach overcomes the heavy weight and corrosion issues of conventional metal shields. Driven by the shift toward high-frequency and integrated electronics, there is an urgent demand for absorption-dominant, lightweight carbon composites to mitigate electromagnetic interference (EMI). This study employs chitosan—a natural resource whose nitrogen atoms induce a self-doping effect—and conductive MWCNTs as the matrix. The fabrication involves impregnating cobalt (Co) and nickel (Ni) precursors into a chitosan/MWCNT aerogel, followed by supercritical drying to preserve a 3D pore network. The aerogel is carbonized under nitrogen.
 The experimental framework has two main axes. First, carbon lattice graphitization and electrical resistance are tracked against heat treatment temperature to elucidate the phase transition of precursors into metal oxides or reduced Co-Ni alloy nanoparticles. The direct impact of these transitions on the electromagnetic interference shielding efficiency (EMI SE) is analyzed. Second, to determine the optimal conditions, the carbonization temperature is systematically varied (500, 600, 700, and 800 °C), and the chitosan concentration is adjusted to control the final density and pore structure. This optimization ultimately aims to maximize the overall shielding performance.
 Consequently, this research establishes a sustainable model by recycling low-cost marine bio-resources into high-value functional materials. The developed aerogel exhibits extremely low density and outstanding EM wave absorption. Thus, it holds great potential as an ultra-lightweight component in next-generation mobility (drones, UAM, EVs) and as a high-performance EMI shielding sheet for electronics under 5G/6G environments.