Microwave activated peach pit carbon enhances S-band electromagnetic absorption performance

Biomass carbon materials have good application prospects in the field of electromagnetic wave absorption and shielding because of their environmental protection and low cost, but not good absorption of low-frequency S-band. In this article, the microwave activation of different mass ratios of zinc chloride and peach pit carbon is studied to improve the low-frequency wave absorption performance. It is found that with the addition of zinc chloride, the electromagnetic absorption performance of peach pit carbon in S-band is significantly improved after microwave activation. The sample with a mass ratio of zinc chloride to peach pit carbon of 3:1 has the best performance. Its minimum reflection loss (RL) is −14.13 dB (4.60 mm, 3.92 GHz), and the maximum effective absorption bandwidth is 1.24 GHz (2.10–3.34 GHz, 5.80 mm). The results of scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and other tests show that the absorption properties of S-band are closely related to the ZnO and basic zinc chloride components generated by microwave activation. In this study, the absorption of carbon material in S-band is achieved by simple microwave activation without the addition of magnetic materials, which can provide a new way for the low-frequency absorption enhancement of materials.