Preparation and microwave absorption properties of ultra-fluffy doped graphene aerogel composites

With the rapid advancement of intelligent communication, the issue of electromagnetic radiation caused by information transmission is becoming increasingly severe. However, traditional microwave absorption materials have limitations such as poor attenuation ability and difficulties in impedance matching, which no longer meet practical applications. In this paper, graphene aerogel (GA) was prepared by hydrothermal synthesis based on the theory of electromagnetic loss, the design strategy of multi-component synergistic loss and the construction of three-dimensional porous aerogel. To enhance its properties, we incorporated MnO₂-coated Ni-Zn ferrite (NiZnFe₂O₄@MnO₂) microspheres with graphene dielectric material to prepare ultra-fluffy magnetically doped graphene-based composite aerogel (NiZnFe₂O₄@MnO₂/GA) powders. The impact of heat treatment temperature and magnetic doping on the wave absorption capability of the composite aerogel was analyzed. Our results demonstrate that at a heat treatment temperature of 300℃ and a nickel-zinc ferrite doping amount of 15wt%, the composite aerogel exhibits optimal absorption performance. At a matching thickness of 2.9 mm, it achieves a minimum reflection loss (RL_min) value of −47.27 dB at a frequency of 8.72 GHz, providing an effective absorption bandwidth (EAB) spanning 3.2 GHz covering most X-band frequencies while maintaining only a packing load rate of 10wt%. The problem of poor material impedance matching is solved, the dielectric loss and magnetic loss capacity of the absorbing materials are optimized. The application requirements of the wave absorbing material for "thin, light, wide and strong" are met.