MXene@Fe₃O₄ microspheres/fibers composite microwave absorbing materials: Optimum composition and performance evaluation

In order to fully utilize the advantages that one-dimensional (1D) materials are conducive to form a conductive network and surface wrinkled microspheres can cause multiple reflection. In this paper, two MXene-based magnetic composites have been innovatively fabricated. 1D MXene@Fe₃O₄ magnetic nanofibers with a diameter of 25 nm are obtained by the self-assembly of single-layer Ti₃C₂Tx MXene nanosheets and coating Fe₃O₄ nanoparticles via thermal decomposition method. The micro-scale surface wrinkled porous MXene@Fe₃O₄ composite microspheres are prepared by simple ultrasonic atomization technology. A high efficiency microwave absorbing system is obtained by blending these two composites. Through the evaluation of microwave absorption performance, the optimal ratio of composite microspheres and nanofibers is conformed to be 7:3. The minimum reflection loss (RL_min) is −63.3 dB at a filler content of 40%. The corresponding matching thickness is 1.8 mm. The maximum effective absorption bandwidth (EAB_max) is 5.2 GHz (12.8–18 GHz). Microwave absorbing mechanism study shows that the attenuation approaches include dielectric loss, magnetic loss, multiple reflection and conductive loss from the unique structure and impedance matching.