Achieving tunable electromagnetic absorber via graphene/carbon sphere composites

This article reports on the design and synthesis of tunable electromagnetic absorbers by loading carbon nanospheres on graphene. In this type of composite, carbon spheres with controllable resistivity are employed for achieving tunable electromagnetic absorbers. The resistivity of carbon spheres played a key role in determining the electromagnetic absorbing property. The synthesis of this graphene/carbon nanosphere composite absorber was conducted under wet-chemical conditions. By adjusting the carbonization temperature of carbon nanospheres, the composite absorber could gain its minimum reflection loss value (RL_min) at a given frequency region. The electromagnetic attenuation mechanism was also proposed and subsequently proved by control experiments with porous graphene/carbon, graphene oxide/carbon, and graphene/carbon composites.