Lightweight, Fire‐Retardant, and Anti‐Compressed Honeycombed‐Like Carbon Aerogels for Thermal Management and High‐Efficiency Electromagnetic Absorbing Properties

Abstract Ordered porous carbon materials (PCMs) have potential applications in various fields due to their low mass densities and porous features. However, it yet remains extremely challenging to construct PCMs with multifunctionalization for electromagnetic wave absorption. Herein, the honeycombed‐like carbon aerogels with embedded Co@C nanoparticles are fabricated by a directionally freeze‐casting and carbonization method. The optimized aerogel possesses low density (0.017 g cm −3 ), fire‐retardant, robust mechanical performance (compression moduli reach 1411 and 420 kPa in the longitudinal and transverse directions at 80% strain, respectively), and high thermal management (high thermal insulation capability and high‐efficiency electrothermal conversion ability). Notably, the optimized aerogel exhibits the excellent electromagnetic wave absorption properties with broad effective absorption bandwidth (13.12–17.14 GHz) and strong absorption (−45.02 dB) at a thickness of only 1.5 mm. Density functional theory calculations and the experimental results demonstrate that the excellent electromagnetic wave absorption properties stem from the synergetic effects among high electrical conductivity, numerous interfaces and dipoles and unique ordered porous structure. Meanwhile, the computer simulation technology (CST) simulation confirms that the multifunctional aerogel can attenuate more electromagnetic energy in a practical environment. This work paves the way for rational design and fabrication of the next‐generation electromagnetic wave absorbing materials.