Interface polarization strategy to prepare Sn/SnO2@C absorber with tunable core compositions and broader frequency absorption properties

Core–shell shaped composites with tunable core compositions have been successfully synthesized by a two-step method. Initial, SnO 2 @C was prepared by fixing the hollow SnO 2 nanospheres into the void of amorphous carbon. Followed by another annealing treatment, SnO 2 was gradually reduced to metallic Sn in a mixed H 2 /N 2 atmosphere and leaded to Sn/SnO 2 or Sn cores. Subsequently, the original SnO 2 hollow nanospheres in the core was collapsed and transformed from clusters to nanoparticles. The electromagnetic absorption properties were significant improved for the binary composite (Sn/SnO 2 @C) as compared to SnO 2 hollow sphere, SnO 2 @C and Sn@C products. The effective absorption frequency width was up to 7.1 GHz with a matched thickness of 1.5 mm. The excellent electromagnetic absorption mechanism was attributed to the balanced impedance matching and attenuation ability. Besides, the existed Sn/SnO 2 interface plays a key role on the attenuation intensity since the boosted interface polarization intensity.