Ni@C/PPy Composites Derived from Ni-MOF Materials for Efficient Microwave Absorption

Ni-MOF, as a metal–organic framework, has the advantages of morphological diversity and adjustable composition, which make its derivatives attractive for electromagnetic wave absorption. However, it is challenging for Ni-MOF derivatives to obtain strong absorption at low filling rates. Herein, ternary Ni@C/PPy composites based on Ni-MOF derivatives were synthesized by cooperatively coupling magnetic Ni@C nanoparticles with a conductive polymer PPy matrix through a facile self-assembly method. Among them, Ni@C nanoparticles are formed after Ni-MOF pyrolysis, and PPy serves as the backbone to effectively assemble and support the Ni@C nanoparticles. As a result, the Ni@C/PPy-3 sample exhibited excellent performance with a reflection loss value of −50.65 dB at a filling ratio of 15 wt% and a thickness of 2.5 mm. At the same time, its effective absorption bandwidth reached 6.24 GHz, covering the whole Ku frequency band. The results show that in comparison to pure Ni@C composite, the Ni@C/PPy multi-component composite with a porous structure shows significant advantages in terms of optimizing impedance matching, which can effectively enhance the interface polarization and, thus, greatly improve its electromagnetic absorption ability. In summary, this work provides a valuable research idea for developing strong absorbing properties of absorbing materials at a low filling rate.