Self-assembly core–shell hollow fly ash sphere-bridged Ti3C2Tx MXene 3D spherical/ lamellar composites with specific electromagnetic wave absorption performance

Abstract

A new A/B spherical/lamellar electromagnetic wave absorption (EWA) model was established, in which A phase was a spherical material with low dielectric constant and B phase was a lamellar 2D material with high dielectric constant. Insulative fly ash cenospheres (FA) and conductive Ti3C2Tx flakes were selected as the A phase and the B phase which acted as the framework (as well as core) and the interface builder (as well as shell) respectively to construct the novel 3D connected structure system via simple self-assembly. FA, a cheap power plants solid waste, was used as an insulating bridge for Ti3C2Tx to help to adjust the conductivity, the electromagnetic parameters and the impedance matching. The synergistic effect of the special heterogeneous structures and the moderate composition of FA and Ti3C2Tx endowed the composites with controllable complex permittivity and excellent EWA performances. FA@T0.35 exhibited a RLmin of − 50.94 dB at 3.5 mm and its widest EAB was 4.25 GHz at 2.0 mm. FA@T0.40 reached a RLmin of − 45.13 dB with an EAB of 4.03 GHz at 2.0 mm. The widest EAB was 4.19 GHz at only 1.5 mm. The work offers a new guideline for designing a high-performance EWA material by using waste materials.