Boosting electromagnetic wave absorption of Ti₃AlC₂ by improving effective electrical conductivity

Electromagnetic wave-absorbing (EMA) materials at high temperatures are limited by poor conduction loss (L_c). However, adding conductors simultaneously increases the conduction loss and interfacial polarization loss, leading to a conflict between impedance matching (Z_in/Z₀) and electromagnetic wave loss. This will prevent electromagnetic waves from entering the EMA materials, finally reducing overall absorbing performance. Here, the effective electrical conductivity (σ) is enhanced by synchronizing particle size and grain number of Ti₃AlC₂ to increase the conduction loss and avoid the conflict between the impedance matching and the electromagnetic wave loss. As a result, the best-absorbing performance with an effective absorption bandwidth (EAB) of 4.8 GHz (10.6–15.4 GHz) at a thickness of only 1.5 mm is realized, which is the best combination of wide absorption bandwidth and small thickness, and the minimum reflection loss (RL_min) reaches −45.6 dB at 4.1 GHz. In short, this work explores the regulating mechanism of the EMA materials of effective electrical conductivity by simulated calculations using the Vienna ab-initio Simulation Package (VASP) and COMSOL as well as a series of experiments, which provide new insight into a rational design of materials with anisotropic electrical conductivity.