Finely modulating the morphology and composition of Cu_xNi_1−x for enhanced microwave absorption capability

Some inevitable disadvantages (being thick and heavy with narrow broadband) restrict the application of Cu-based absorbers in microwave absorption field, which can be overcome by finely modulating the morphology and component of 1D structures. Here, we reported ethylenediamine-steered in situ two-step reduction reactions, which allowed the tunable preparation of Cu_xNi_1−x (x = 0, 0.005, 0.02, 0.0344, 0.0934, 0.1581, 0.2243, and 1) composites with continuously tunable components and morphology varying from smooth rods to urchin-like rods and microspheres. The recombination of Ni with Cu into Cu_xNi_1−x composites can tune crystallite size, inner stress, lattice constant, component, shape as well as properties. The Cu_xNi_1−x (x = 0.0344–0.1581) composites exhibited stronger and wider absorption band under a lower filling mass fraction and thinner sample than other Cu-based absorbers. Due to the combined action of double dielectric relaxation, double magnetic resonances, high attenuation, and good impedance match. The optimal microwave absorption capability (MACs) was achieved for Cu_0.0344Ni_0.9656 microspheres with a maximum RL value of − 67.5 dB at 14.74 GHz and a broad frequency band (99% attenuation) of 15.41 GHz, corresponding to 1.7–10 mm sample thickness. Owing to tunable saturation magnetization and excellent MACs, the Cu_xNi_1−x composites can work as a kind of promising absorber for applications in electronic equipment and devices.