C/MnO@void@C with Triple Balances for Superior Microwave Absorption Performance

Abstract

It is very promising and challenging to construct a yolk–shell structure with highly efficient microwave absorption (MA) performance through a simple fabrication process. Here, a novel C/MnO@void@C (MCC) yolk–shell structure has been successfully synthesized by one-step calcination without additional processing. The as-obtained MCC composites with tunable crystallinity degrees and hollowness can be obtained by treatment at various temperatures. The MCC composites treated at 700 °C (MCC-700) show an impressive MA performance, and the optimal reflection loss of −53.2 dB and an effective absorption bandwidth of 5.4 GHz can be obtained. This excellent performance results from multiple balance mechanisms. First, the regulated permittivity of MCC-700 due to proper crystallinity and hollowness is beneficial for the balance between dielectric loss (tan δε) and impedance match (Z im). Second, the optimal balance between the increasing polarization range and decreasing polarization intensity can be achieved, which is favorable for the improvement of the MA performance. Third, the multicore yolk–shell structure of MCC-700 is conducive to multiple scattering and continuous energy dissipation. Thus, our new findings provide a rational way for the utilization of yolk–shell structural manganese-based materials.

Fe-Doped MnO2 Nanostructures for Attenuation–Impedance Balance-Boosted Microwave Absorption

“…A large number of electromagnetic waves in free space cause severe electromagnetic radiation pollution, which threaten information security and human health. In order to solve the negative impact brought by the development of technology, electromagnetic wave protection technology has gradually become a popular research field. − One of the solutions is to develop electromagnetic wave absorption materials that can convert electromagnetic energy into other forms of energy through the electrical and magnetic interaction with electromagnetic waves. − At present, the main plight of absorbing materials is how to balance the attenuation and impedance performance, which limits their absorption performance. − …”

Selective assembly of magnetic nano-antenna for electromagnetic dissipation

“…1e2). [37][38][39][40] While, altering the reducing temperature to 400 C (FSF-400), the morphology remains perfect with no apparent agglomeration of the outmost magnetic particles (Fig. S2c1 †).…”

Gravity-induced single-layer gradient structure of Ni@Ti3C2Tx/PVA for enhanced microwave absorption

“…However, the accompanying electromagnetic (EM) radiation can cause malfunction of electronic devices and threaten people's health. [1][2][3][4][5][6][7][8][9] Therefore, EM absorbing materials are in urgent need. High-performance EM absorbing materials require good impedance matching and strong lossy ability.…”