Preparation of Co@C composite with ultra-wide microwave absorption bandwidth

Co@C composite with an ultra-wide microwave absorption bandwidth was prepared using Co-organic framework@phenolic resin (Co-MOF@PR) as a precursor. In comparison with other composites, the prepared Co@C composite exhibited a wider effective absorption bandwidth (Table 1). At 2.8 mm matching thickness, the obtained minimum reflection loss (RL) was −48.02 dB and the effective absorption bandwidth (RL < -10 dB) was up to 8.20 GHz (9.65–17.85 GHz). The excellent properties can be attributed to the good co-frequency synergy between dual polarization relaxation and dual exchange resonance which greatly improves the impedance matching and dielectric properties of the composite. These results suggested that the prepared Co@C composite can be used for high-frequency (10–18 GHz) microwave absorption.