In-situ fabrication of Ni2⁺/Zn2⁺-polydopamine complex derived FeCo@C/Ni@C cubic nanocages towards enhanced electromagnetic performance

The quest for broadband electromagnetic wave absorption to satisfy the demands of various fields has emerged as a prominent research focus in the domain of electromagnetic wave absorption. By considering the effects of magnetic loss and polarization loss across different frequency bands, the development of composite materials incorporating magnetic metal particles and single metal atoms may facilitate an expansion of the electromagnetic wave absorption frequency range. Consequently, we synthesized FeCo@C/Ni@C composites derived from FeCo Prussian blue analogues and polydopamine through wet chemistry and pyrolysis methods. The chelation mechanism of polydopamine, combined with the physical barrier effect provided by Zn ions during synthesis, endows the FeCo@C/Ni@C composite with low-frequency magnetic loss characteristics from the FeCo alloy, high-frequency dipole polarization losses attributed to Ni atoms, and conductivity losses arising from the coupled carbon matrix. Ultimately, the composite exhibits exceptional electromagnetic wave absorption performance: at a thickness of 2.26 mm, it achieves a minimum reflection loss value of − 50.1 dB along with an effective absorption bandwidth reaching up to 6.0 GHz. In summary, this work presents a novel strategy for enhancing broadband absorption capabilities in electromagnetic wave absorbing materials.