Multiple Interfacial Polarization from 3D Net-Like ZnO@MWCNTs@NiFe2O4 Nanocomposites as Broadband Microwave Absorbers

Abstract The design of multiple heterogeneous interfaces has been proven to be a successful strategy to boost microwave absorption performance. However, the synthesis of magnetic microwave absorber with wide absorption bandwidth is still a challenge. In this work, ZnO@MWCNTs@NiFe2O4 nanocomposites are fabricated by introducing ZnO on the surface of MWCNTs and subsequent anchoring of NiFe2O4. The minimum reflection loss can reach −45.5 dB at 12.4 GHz with a thickness of 2 mm, while the broadest efficient absorption bandwidth is above 6.4 GHz at only a 3 mm thickness. Furthermore, the microwave absorption performance of ternary nanocomposites can be optimized by tunable the content of ZnO and NiFe2O4, whose microwave absorption mechanism depends on the synergy of dielectric loss and magnetic loss. The formation of 3D conductive network and heterogeneous interfaces contributes to the enhancement of conductive loss and polarization, respectively. The experimental results demonstrated that the ZnO@MWCNTs@NiFe2O4 nanocomposites can provide a guide for microwave absorbers with wide absorption bandwidth in the future.