Governing the Ni content and size of 2D layered C/Ni nanoparticle composites for enhanced electromagnetic wave absorption

The size and dispersity of magnetic metal absorbents need to be controlled for the inhibition of the eddy current and the enhancement of electromagnetic wave absorption performance (EMWAP). Herein, layered C/Ni nanoparticle (NP) composites were developed as an excellent electromagnetic wave absorbent via the size and dispersity control. The synthesis of layered C/Ni NP composites was achieved via a simple one-step calcination process. The amount of nickel acetate (n) and calcination temperature (Tc) were changed to not only control the diameter, content, and dispersity of Ni nanoparticles, but also adjust the electric/magnetic properties and EMWAP of layered C/Ni NP composites. The superior EMWAP was obtained at n = 3.99 mmol and Tc = 600 °C with high assimilation (−39.46 dB), thin thickness (2.3 mm), and broad bandwidth (9.68 GHz) in a low loading rate (25 wt%). Our results suggest that excellent EMWAPs relies on the cooperation of multiple polarization loss, multiple resonances, eddy current loss, electric/magnetic coupling, and good impedance matching. The synthetic method adopted in this work has advantages of simple operation, low cost, and high yield, which is recommended to other 2D materials.