Enhanced electromagnetic absorption properties of the double-layer Ti₃C₂T_x MXene absorber with orthogonal microstructures

Transition metal carbides and nitrides (MXenes) with excellent properties have broad prospects in electromagnetic wave absorption (EMA). In this paper, a unidirectional freeze-casting method was utilized to design a double-layer MXene absorber with orthogonal microstructures. The perpendicular and parallel samples (associated with the unidirectional freeze-casting direction), perform their respective roles in the designed double-layer absorber. The perpendicular sample with various attenuation techniques is employed as an electromagnetic wave attenuation layer, while the parallel sample with good impedance matching conditions is utilized as an impedance matching layer. Consequently, the entire absorber exhibits favorable EMA characteristics. Upon incidence of electromagnetic waves onto the parallel terminus, it is observed that the sample measuring 4.6 mm in thickness exhibits a minimal reflection loss (RL_min) of −60.8 dB at a frequency of 6.63 GHz, with a parallel end thickness accounting for 25%. In addition, the sample with a thickness of 2.6 mm displays a noteworthy maximal effective absorption bandwidth (EAB) amounting to 9.4 GHz, given a parallel end thickness of 20%. A thorough analysis of the impedance matching conditions and electromagnetic wave attenuation mechanisms of each sample reveals that the double-layer MXene absorbers with orthogonal microstructures can significantly increase the viability of MXenes in EMA.