Novel Microwave Absorption Materials of Porous Flower-Like Nickel Oxide@Polyaniline in the X-Band

Porous flower nickel oxide@polyaniline (NiO@PANI) composites as excellent microwave absorption (MA) materials in the X-band were synthesized via a two-step strategy in this work. The porous NiO flower is uniformly dispersed and homogeneous in particle size after Ostwald ripening process. Coating conductive PANI on the surface of porous NiO microspheres could improve interfacial polarization and dielectric loss property that will lead to a great improvement of MA properties. Electromagnetic (EM) parameters of NiO@PANI composites with different NiO contents were investigated by a vector network analyzer and the reflection loss (RL) values with varied thickness were also calculated. The results showed that the effective absorption bandwidths ([Formula: see text][Formula: see text]dB) of all NiO@PANI composites can cover the whole X-band. Especially, the NiO@PANI[Formula: see text] composite is able to attenuate microwave energy in the X-band with the thickness of 2.5[Formula: see text]mm. The NiO@PANI[Formula: see text] has a maximum RL of [Formula: see text][Formula: see text]dB at 10.1[Formula: see text]GHz and the effective absorption bandwidths cover 4.64[Formula: see text]GHz (11.12–15.76[Formula: see text]GHz) at 2.0[Formula: see text]mm. The excellent MA absorption performance may be ascribed to the polarization effect, dielectric loss and structure of porous flower-like NiO@PANI. Our work confirms that the synthesized NiO@PANI composite is an attractive candidate as a highly efficient MA material in the X-band.