Construction of highly ordered porous electromagnetic coupling Co/CoO/C aerogels for enhanced electromagnetic wave absorption performance

Fabricating electromagnetic coupling carbon-based aerogels with tightly bound and uniformly distributed components is a proven strategy for improving electromagnetic wave absorption (EWA) performance. Herein, highly ordered porous cobalt/cobalt (II) oxide/carbon (Co/CoO/C) aerogels were successfully fabricated via ice-templated freeze casting coupled with one-step carbonization, relying on the complexation reaction between cobalt ions and chitosan. The optimal sample, Co/CoO/C-1.0, achieves a minimum reflection loss (RL m ᵢ n ) of −58.15 dB and an effective absorption bandwidth (EAB) of 6.48 GHz at a thickness of 2.2 mm. Additionally, the aerogel exhibits excellent radar stealth performance (with a significant reduction in radar cross-section, RCS) and thermal insulation properties. Gradient structural design effectively extends the effective absorption bandwidth (EAB) to 11.23 GHz. Mechanism analysis reveals that the outstanding EWA performance of these aerogels stems from the synergistic effect of diverse attenuation pathways, including multiple scattering, dipole polarization, interfacial polarization, conduction loss and magnetic resonance. The regulation of cobalt content effectively achieves an optimal balance between impedance matching and electromagnetic loss. This multifunctional Co/CoO/C aerogel integrating EWA, radar stealth and thermal insulation capabilities possess great application prospects under complex service conditions and provide critical guidance for the rational design of carbon-based EWA absorbers. The highly ordered porous electromagnetic coupling Co/CoO/C aerogel was synthesized. The optimized aerogel achieves a minimum reflection loss (RL m ᵢ n ) of −58.15 dB and an effective absorption bandwidth (EAB) of 6.48 GHz at a thickness of 2.2 mm. The gradient multilayer structural design effectively broadens the effective absorption bandwidth (EAB) to 11.23 GHz. Download: Download high-res image (393KB) Download: Download full-size image