Synergetic dielectric and magnetic losses of melamine sponge-loaded puffed-rice biomass carbon and Ni3ZnC0.7 for optimal effective microwave absorption

Multi-dimensional design and the combination of multiple phases can effectively enhance the dielectric loss properties and multiple reflection effects of absorbers. Herein, a novel multi-dimensional microporous nanostructured composite, melamine sponge (MS) loaded puffed-rice biomass carbon (C) together with bimetallic carbide material Ni3ZnC0.7 (Ni3ZnC0.7-MS/C) was synthesized by simple vacuum filtration and hydrothermal calcination. The result indicates that small Ni3ZnC0.7 particles with little Ni doping uniformly decorated on the surfaces of the three-dimensional (3D) melamine sponge and puffed rice carbons. The Ni3ZnC0.7-MS/C composite mixed with paraffin (weight ratio of 1:2) exhibited the best electromagnetic wave (EMW) absorption performance, and the minimum reflection loss (RLmin) value of the Ni3ZnC0.7-MS/C composite reaches -107.7 dB with a matching thickness of 2.78 mm and the maximum effective absorption bandwidth for RL below -10 dB (EABmax) is adjusted to 9.2 GHz at a matching thickness of 4.0 mm. The dipole polarization effect of the N doping and the different interfaces provided by the 3D structure of the MS carbon enhance the conduction loss and interface polarization, while the positive effects of eddy current and resonance caused by Ni3ZnC0.7 effectively improve the microwave absorption performances. This melamine sponge-loaded bimetallic carbon composite exhibited a magnetic/dielectric loss combination, resulting in a high-performance absorber with lightweight, cost-effective and efficient properties.