Graphene decorated by Co₂(OH)₃Cl: A promising lightweight wideband microwave absorber

A wideband microwave absorber is requested to have the impedance matching and attenuation ability, which can be realized by the general strategy of component-optimization. Taking graphene-based hybrids for an example, the impedance matching ability can be significant improved when combining graphene with others components with lower dielectric properties. However, the benefited component usually has poor dielectric loss ability undermining the overall attenuation ability. To address this issue, this research reports a progress on the nanostructure of promising component by the in-situ growth of nanoflake-like Co₂(OH)₃Cl on graphene, which is favorable for boosting the dielectric-response to the microwaves. As a result, the composite showed superior performance with the ultralow density of merely 0.1 ± 0.01 g/cm³. A minimal reflection loss (R_L) value of −52 dB could be achieved with a loading ratio of 20 wt% with a thickness of merely 1.42 mm. Meanwhile, the qualified frequency region is ∼3.44 GHz. To investigate the attenuation mechanism, more Co₂(OH)₃Cl/graphene hybrids were developed by tuning the reaction conditions, e.g., pH values, starting amount of Co slates etc. Synthesizing nanocomposite of Co₂(OH)₃Cl and graphene opens a new avenue toward the more efficient electromagnetic absorption devices.