Dielectric regulation of high-graphitized fine ash wrapped cube-like ZnSnO3 composites with boosted microwave absorption performance

Intrinsic dielectric properties and tuning conductivity play important roles in microwave absorption. Novel multi-interfaced ZnSnO₃@ fine ash (ZSFA) composite was successfully synthesized by coating cube-like ZnSnO₃ particles with highly graphitized gasification fine ash. After hydrothermal reaction and Ostwald ripening process, fine ash was tightly wrapped around the assembly of ZnSnO₃ particles. Related electromagnetic parameters and dielectric dissipation ability were discussed with different mass additions. Owing to the strong polarization relaxation, special conductive network, and multi-interface structural design, the as-synthesized ZSFA exhibited adjustable dielectric loss behaviors and efficient microwave absorption ability. When 50% mass added, the maximum reflection loss value of the obtained ZSFA-2 is ?47.8 dB at 2.5 mm thickness, showing the enhanced dielectric loss ability. Meanwhile, the widest effective absorption bandwidth (RL ≤ ?10 dB) can cover 7.0 GHz (11.0–18.0 GHz) at a thickness of only 2.2 mm, which included the entire Ku band. This unique pure dielectric composite exhibited high-performance electromagnetic wave attenuation property and broadband frequency response, thereby providing a new approach to the production of a superior microwave absorber.