Achieving 9.11 GHz broadband microwave absorption in CeO₂/Sn@C composites via Sn doping and structural modulation

Broom-like CeO 2 /Sn@C nonmagnetic absorbers were rationally designed. • Surface Sn spheres create heterointerfaces and strengthen polarization loss. • An ultrabroad EAB of 9.11 GHz is achieved at 2.57 mm thickness. • RL min reaches −60.68 dB with only 10 wt% absorber loading. • DFT confirms charge redistribution across CeO 2 /C/Sn heterojunctions. Broom-like CeO 2 @C composites with Sn doping and surface modification by metallic Sn spheres are successfully synthesized. At a Ce/Sn ratio of 10:1, metallic Sn spheres precipitate on the surface of CeO 2 /Sn@C. At an annealing temperature of 800 °C and a filler loading of 10 wt%, CeO 2 /Sn@C composite achieves a minimum reflection loss (RL min ) of −60.68 dB and an effective absorption bandwidth (EAB) of 9.11 GHz at a matching thickness of only 2.57 mm. Compared with CeO 2 @C, the conductivity of CeO 2 /Sn@C increases from 0.2407 to 0.5383 S∙m −1 , which lead to a remark improvement in absorption performance. Density functional theory (DFT) calculations are further performed to analyze and verify the electromagnetic wave (EMW) absorption mechanisms. Both experimental and theoretical results confirm that the introduction of metallic Sn substantially improves the microwave absorption properties of CeO 2 @C, rendering it a high-efficiency EMW absorbing material with promising application prospects. The table of contents entry: Broom-like CeO 2 @C composites modified by Sn doping and metallic Sn surface precipitation are constructed through solvothermal synthesis and thermal treatment. The optimized CeO 2 /Sn@C composite exhibits enhanced electromagnetic wave absorption behavior, which is mainly attributed to improved conductivity, interfacial polarization, and multiple scattering effects. Download: Download high-res image (206KB) Download: Download full-size image