MOF-derived porous hollow Ni/C composites with optimized impedance matching as lightweight microwave absorption materials

Electromagnetic wave (EM) pollution caused by rapid development of electric devices has been threatening people's lives. Thus, the need for high-performance and lightweight microwave absorption materials is becoming more and more urgent. In this concern, this paper reported the successful fabrication of Ni/C composites by adopting the MOF-derived method. The as-prepared Ni/C composites delivered porous and hollow structures with diameters of 1.0-2.0 mu m. Their microwave absorption performances were investigated in calcination temperature ranges of 600-800 degrees C. When tested for microwave absorption, the porous hollow Ni/C microspheres displayed outstanding microwave absorption performances. With a filling ratio of 30 wt%, the porous hollow Ni/C microspheres obtained at 600 degrees C exhibited minimal reflection loss (RL) of - 32.3 dB at thickness of 1.5 mm. The effective bandwidth with RL below - 10 dB achieved 4.4 GHz with 1.61-mm thickness. For porous hollow Ni/C microspheres obtained at 700 degrees C, the optimal RL reached - 55.4 dB at 1.53 mm. The results could push the development of MOF-derived magnetic carbon materials as lightweight microwave absorbers with strong absorption.