Core-shell Si3N4@WS2 porous ceramics with improved electromagnetic wave absorption performance

Ceramic-based absorbing materials have attracted extensive attention in electromagnetic wave (EMW) absorption because they are lightweight and exhibit strong dielectric loss. However, there is still a need for developing the microstructure design of ceramics, and this hinders the further improvement of absorption properties. In this study, core-shell Si3N4@WS2 porous ceramics, with the wave-transmitting phase Si3N4 as the core and the wave-loss phase WS2 as the shell, were prepared using a simple impregnation-hydrothermal method. The core-shell structure provided as large a contact area as possible between WS2 and Si3N4, promoting the formation of heterogeneous interfaces. The as-prepared core-shell Si3N4@WS2 porous ceramics exhibited excellent EMW absorption properties. When thickness was 3.92-4.22 mm, an effective absorption bandwidth of 4.20 GHz was achieved, covering the entire X-band (8.2-12.4 GHz). At a thickness of 4.35 mm, the minimum reflection loss was -65.03 dB. The outstanding EMW absorption performance was attributed to the special core-shell microstructure inducing interfacial polarization loss and optimizing the impedance matching of the material. The findings of this study provide novel insights and feasible strategies for designing ceramic-based absorbing materials with core-shell structures.