Impedance-attenuation balance on Ni@CN/WO3-δ ternary composites to enhance microwave absorption

The Ni@CN/WO3-δ ternary composites were constructed by a two-step method in this work, which includes solid-phase pyrolysis and arc-discharging technology. Herein, the content of WO3-δ in Ni@CN/WO3-δ ternary composites was adjusted utilizing the precursor H2WO4 amount. The result shows that the appropriate WO3-δ content in Ni@CN/WO3-δ ternary composites can effectively contribute to their cooperativity for electromagnetic parameters and impedance matching. As a result, the optimal reflection loss of the Ni@CN/WO3-δ ternary composites can achieve in -42.4 dB at a thickness of 2.0 mm, and an efficient absorption bandwidth is 4.08 GHz at a matching thickness of only 1.7 mm. The study further reveals that the synergistic effects between the oxygen vacancies from appropriate WO3-δ and the high conductivity of CN lead to the balance between impedance matching and attenuation capacity of the Ni@CN/WO3-δ ternary composites, resulting in excellent microwave absorption performances. This work gives a feasible strategy for preparing high-performance microwave absorbents by oxygen vacancies engineering in the future.