Synthesis of daisy-like vanadium nitride powders with excellent microwave absorption properties

The daisy-like vanadium nitride powders were synthesized via solvothermal combined with ammonia reduction nitridation method. The results of XRD and XPS showed that the sample was mainly cubic vanadium nitride phase and also contained abundant valence states of V element. Moreover, the residual oxygen element still existed in daisy-like vanadium nitride powders due to the inadequate reduction nitriding reaction, which is positive to generate abundant defects in the samples and is conducive to impedance matching. Meanwhile, the defect-rich samples favored the interfacial polarization effect. The daisy-like structure produced a large number of interfaces and pores, which promoted conductivity loss, interface polarization, multiple reflections, and scattering of electromagnetic waves. Hence, the daisy-like vanadium nitride powders exhibit distinguished reflection loss (RL) performance with RL values of − 56.7 dB (1.38 mm) and the optimal effective absorption bandwidth (EAB) of 4.13 GHz (1.6 mm). Furthermore, the EAB covers the entire X and Ku bands by adjusting the thickness (1.3–2.5 mm).