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 (T_c) 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 T_c = 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.

为了抑制涡流和增强电磁波吸收性能（EMWAP），需要控制磁性金属吸收剂的尺寸和分散度。在此，层状 C/Ni 纳米颗粒 (NP) 复合材料通过尺寸和分散性控制被开发为一种优异的电磁波吸收剂。层状 C/Ni NP 复合材料的合成是通过简单的一步煅烧过程实现的。改变醋酸镍的用量 ( n ) 和煅烧温度 ( T _c )，不仅可以控制 Ni 纳米粒子的直径、含量和分散性，还可以调节层状 C/Ni NP 复合材料的电/磁性能和 EMWAP。在n  = 3.99 mmol 和T_c  = 600 °C，具有高同化 (-39.46 dB)、薄厚度 (2.3 mm) 和宽带宽 (9.68 GHz)，负载率低 (25 wt%)。我们的结果表明，优秀的 EMWAP 依赖于多重极化损耗、多重谐振、涡流损耗、电/磁耦合和良好阻抗匹配的协同作用。本工作采用的合成方法具有操作简单、成本低、收率高等优点，推荐用于其他二维材料。