Microwave Absorption Performances Of Conductive Carbon Nanotubes Network Composite With CH₃NH₃PbI₃ And NiCo₂

In the research of new-style microwave absorption materials,carbon nanotubes（CNTs）have the high dielectric constant because of the excellent conductivity.However,a large number of electromagnetic waves are reflected off the surface of the material because of the high dielectric constant,and only a small amount of electromagnetic waves are injected.It displays that the microwave absorption ability is very poor.The research shows that CNTs have a conductive network structure.By combining the dielectric materials and magnetic materials,the composite materials will have an excellent microwave absorption performance.In this paper,the CNTs has composited the perovskite material（CH₃NH₃PbI₃）and magnetic nanoparticle（NiCo₂）respectively,to adjusted the electromagnetic parameters and improve the microwave absorption performance of the composite materials.The CH₃NH₃PbI₃ and CH₃NH₃PbI₃/CNTs have been synthesized by a situ solution method.The CNTs conductive network uniformly encapsulated the CH3NH3PbI3particles,and the CH3NH3PbI3 particles gradually reunited and growed as the decreases of CNTs.The electromagnetic parameters of the sample/paraffin mixture were tested,and calculated the reflection loss.The results indicated that CH₃NH₃PbI₃/CNTs-5/1 showed the good microwave absorption.At the thickness of 1.3 mm,the minimum reflection loss of-35.7 dB was found at 13.1 GHz,and the bandwidth of the reflection loss values less than-10 dB（90%absorption）was 2.4 GHz（11.7¹4.1 GHz）.Moreover,the reflection loss values less than-20 dB（99%absorption）were observed at 5¹6.8 GHz with the thickness of 1.0³.5 mm.The NiCo₂ and NiCo₂/CNTs have been synthesized by hydrothermal and calcination reduction method.The NiCo₂ nanoparticles were uniformly attached to the CNTs,and the number of large NiCo₂ particles increased with the decrease of CNTs gradually.The electromagnetic parameters of the sample/paraffin mixture were tested,and calculated the reflection loss.The results indicated that NiCo₂/10%CNTs showed the good microwave absorption.At the thickness of 1.3 mm,the minimum reflection loss of-25.5dB was found at 14.7 GHz,and the bandwidth of the reflection loss values less than-10dB was 4.4 GHz（12.5¹6.9 GHz）.In addition,the reflection loss values less than-20 dB were observed at 3.7¹6.5 GHz with the thickness of 1.2⁴.0 mm.