Facile and scalable preparation of Ni/NiO/SiO2@porous carbon network with strong and wide bandwidth microwave absorption

Researchers are exploring high-performance electromagnetic wave absorbing materials to mitigate electromagnetic interference, focusing on minimizing surface reflection and enhancing attenuation capability. However, one single component and structure struggle to meet the aforementioned requirements. Here, a Ni/NiO/SiO 2 @porous carbon network (Ni/NiO/SiO 2 @PCN) with porous structures is synthesized via a pyrolysis process. The magnetic Ni/NiO and dielectric SiO 2 nanoparticles are uniformly dispersed within the PCN matrix. The absorption capability of the material can be controlled by adjusting the SiO 2 content in Ni/NiO/SiO 2 @PCN. Particularly, when the SiO 2 loading is 0.5 wt%, the resulting Ni/NiO/SiO 2 @PCN-0.05 demonstrates outstanding EMW absorption properties, exhibiting strong broadband absorption attributed to its 3D porous architectures, the hybrid composition of Ni/C, NiO/C, and SiO 2 /C, and good impedance matching. At a filler loading of 20 wt%, the Ni/NiO/SiO 2 @PCN-0.05 achieves remarkable EMW absorption performance, with a minimal reflection loss reaching −71.42 dB at 2.6 mm and 11.18 GHz, and an effective absorption band extending over 6.24 GHz within the frequency range of 11.52 to 18.0 GHz at a thickness of 2.25 mm, effectively covering the entire K u band. This study introduces a cost-effective and efficient fabrication approach for producing high-performance microwave absorbers, thereby offering promising prospects for applications in the field of microwave telecommunications.