Excellent microwave-absorption performances by matched magnetic–dielectric properties in double-shelled Co/C/polyaniline nanocomposites

Double-shelled Co/C/polyaniline (Co/C/PA) nanocomposites were prepared by combining the arcdischarge process and in situ chemical oxidative polymerization reaction. The effects of PA shells on the magnetic properties of Co/C/PA nanocomposites were studied, and the electromagnetic properties of Co/C/PA-paraffin composites were investigated in the 2-18 GHz frequency range. The reflection loss (RL) exceeding -10 dB is obtained in 9.9-16.4 GHz for an absorber thickness of 2.5 mm, which covers almost half of the X-band (8-12 GHz) and most of the Ku-band (12-18 GHz). Moreover, some strong absorption peaks exceeding -40 dB can be observed in the low-frequency range (3.5-5.5 GHz). These excellent absorbing performances show that the Co/C/PA nanocomposites have great potential for application in a microwave-absorption field for their strong absorption and broad bandwidth.