Rational construction of hierarchical accordion-like Ni@porous carbon nanocomposites derived from metal-organic frameworks with enhanced microwave absorption

Development of high-performance microwave absorption materials with a thin matching thickness, wide effective absorption bandwidth, low filler loading, and strong absorption capacity has attracted extensive scientific and technological interest and it remains a huge challenge. Here, hierarchical accordion-like Ni@porous carbon (Ni@C) nanocomposites derived from metal-organic frameworks were rationally designed and successfully developed as enhanced microwave absorption materials. It was found that the well-tuned composition (Ni, C and CNTs) and structure (laminated, porous, and core-shell characteristics) of the resultant nanocomposites led to the variation of magnetic properties, graphitization degree, and electromagnetic parameters. As expected, the hierarchical accordion-like Ni@C nanocomposites with a low filler loading of 25 wt% achieved a broad effective absorption bandwidth of 6.6 GHz, a strong reflection loss of-86.9 dB with a thin thickness of 1.8 mm through the optimization of impedance matching and improvement of microwave attenuation ability. The enhanced microwave absorption was attributed to the loss synergistic effect between abundant interfacial and dipole polarization in the hierarchical architecture, to the electronic transport in the three-dimensional conductive network, and to strong magnetic coupling in Ni nanoparticles. Therefore, this work presented a tailored strategy for the development of novel hierarchical nanocomposites as enhanced microwave absorption materials. (C) 2020 Elsevier Ltd. All rights reserved.