Two Birds with One Stone: Dual-Regulation Interfacial Polarization and Scattering Loss of Tin Dioxide/Graphene Electromagnetic Wave Absorbing Materials

Tin dioxide (SnO₂) is an n-type semiconductor with strong dielectric properties and a unique electromagnetic loss mechanism. Therefore, a “kill two birds with one stone” strategy was used to improve the wave-absorbing properties of the material. The first one stone refers to the construction of tin dioxide/reduced graphene oxide composites by varying the ratio, thus modulating the two wave-absorbing mechanisms of the material (two birds: polarization loss and scattering loss). Morphological characterization showed that the prepared SnO₂/RGO composites had a unique embedding distribution and porous network structure consisting of tin oxide nanoparticles adorned on the wrinkled surfaces of flaky RGO. Optimal tuning of the graphene concentration leads to a significant rise in the number of interfaces, both within the graphene layers and at the boundary between graphene and tin dioxide (SnO₂), within the material. The interfaces not only enhance the polarization effect but also lead to an increase in the scattering and reflection paths of electromagnetic waves within the material, and the graphene lamellae can form an ordered arrangement structure through van der Waals forces. This structure makes the material show regular electromagnetic wave scattering and absorption behavior on the microscopic scale. The composite with a thickness of 2.5 mm shows the minimum reflection loss value of −39.09 GHz at a graphene concentration of 3 mg/mL.