The Synergy of Multiple Polarization Effect to Boost Electromagnetic Energy Absorption

ABSTRACT Polarization relaxation has been regarded as an effective approach to convert electromagnetic energy into thermal energy by enhancing the dielectric loss of electromagnetic wave (EMW) absorbers. However, it is still challengeable to effectively construct multiple polarization centers to achieve broadband absorption. Herein, we design a novel self‐stacked structure that is constructed via stacking of nCo@NC (∼15 nm Co nanoparticles on the nonporous carbon) and pCo@NC (∼150 nm Co nanoparticles on the porous carbon). In such a micrometer‐scale heterogeneous interface model, the asymmetric charge densities and different interfacial distances between nCo@NC and pCo@NC induce abundant polarization centers to absorb the EMW at middle‐frequency. Furthermore, ∼15 and ∼150 nm Co nanoparticles form novel large dipoles by means of NC connection sites, which yield novel resonance around 10.0 GHz. And these Co particles, Co single atoms, and pore defects can facilitate strong absorption at high frequencies. As a result, the self‐stacked absorber exhibits an excellent reflection loss value of −125.8 dB with an effective absorption bandwidth of 11.0 GHz at 2.5 mm. Based on this model, the relationship between diploe moments and EMW responding frequency has been clarified, which provides an important reference to understand the multiple polarization mechanisms and design ultra‐broadband EMW systems.