Synthesis and Characterization of Co 3 O 4 /rGO Composite Magnetic Microwave Absorbing Materials

To prepare high-performance microwave absorbing materials, Co 3 O 4 /reduced graphene oxide (rGO) composite materials were prepared from graphite powder and cobalt acetate by a simplified hydrothermal method. It is demonstrated that the reflection loss (RL) and effective absorption bandwidth (EAB) of Co 3 O 4 /rGO composites can be adjusted in accord of demands. By changing the thickness and the compositional ratio of the material, the electromagnetic parameters, attenuation constant and eddy current effect of the material can be adjusted to obtain desired outcomes. The EAB of Co 3 O 4 /rGO composites can cover 97.5% of 4–18 GHz band when thickness is 2–5 mm. The maximum RL of the obtained composite reached -64.8 dB when the thickness was 2.8 mm, and the maximum EAB was 9.63 GHz when the thickness was 3.0 mm. Because of its lamellar micromorphology, Co 3 O 4 /rGO prepared in this study has made a breakthrough in its microwave absorption properties such as the highest reflection loss and effective absorption bandwidth. The result of this study provided a new approach for designing microwave absorption capacity.