Core-shell structured Ag@SiO2 microspheres: A promising candidate for electromagnetic absorption

The rapid advancement of social information substantially expands the application range of electromagnetic technology and leads to a significant increase in electromagnetic wave pollution. In this study, silver ions undergo sensitization, activation, and subsequent reduction processes, the silver shell is formed on SiO2 matrix. Microstructure, morphology, and electromagnetic wave absorption performance of as-prepared Ag@SiO2 and SiO2 were explored. When the Ag content reaches 10 wt%, the shells achieve a dense coating on the matrix. The results demonstrate that the Ag@SiO2 (10 wt%) composite achieves a remarkable reflection loss of -52.48 dB and an absorption bandwidth of 2 GHz, at an absorber thickness of 5.3 mm and a frequency of 4.96 GHz. Compared to the reflection loss of -2.5 dB exhibited by SiO2, it showcases excellent electromagnetic wave absorption capability. Such significantly enhanced absorption capability of Ag@SiO2 composites can be attributed to local surface plasmon resonance behavior induced at the interface. This study elucidates the electromagnetic wave absorption mechanism of the Ag@SiO2 composite and successfully demonstrates its potential as a high-performance composite for electromagnetic wave absorption. Consequently, it provides a feasible solution to address the challenges associated with electromagnetic pollution.