Metal-organic-frameworks derived porous carbon-wrapped Ni composites with optimized impedance matching as excellent lightweight electromagnetic wave absorber

In recent years, metal-organic-frameworks derived composites, especially magnetic nanoparticles embedded in porous carbon matrix have emerged as promising candidate for lightweight electromagnetic wave absorber. Nevertheless, investigation on the optimization of impedance matching in the microwave absorption properties is insufficient. In this work, impedance matching is optimized to achieve strongest absorption intensity and broaden the effective frequency bandwidth. In detail, electromagnetic parameters have been controlled through changing the carbonization temperature to fulfill optimized impedance matching. RL value of -51.8 dB and an effective frequency bandwidth (f(e)) of 3.48 GHz with a thickness of 2.6 mm can be achieved by sample prepared at 500(circle)C and RL value of -15.0 dB and a f(e) of 4.72 GHz with a thin thickness of 1.8 mm can be reached by sample synthesized at 600(circle)C. Comparative studies of each sample directly display the effect of impedance matching on the RL performance and possible attenuation mechanisms are also discussed. This work may deepen the understanding of the impedance matching and pave the way for the synthesis of high performance lightweight microwave absorber. (C) 2016 Elsevier B.V. All rights reserved.