Magnetic coupling engineered porous dielectric carbon within ultralow filler loading toward tunable and high-performance microwave absorption

Developing microwave absorption(MA)materials with satisfied comprehensive performance is a great challenge for tackling severe electromagnetic pollution.In particular,the magnetic component/carbon hybrids absorbers always suffer from high filler loading.Herein,we propose a feasible strategy to construct hierarchical porous carbon with tightly embedded Ni nanoparticles(Ni@NPC).These highly dispersed Ni nanoparticles produce strong magnetic coupling networks to enhance magnetic loss abilities.Moreover,the interconnected hierarchical dielectric carbon network affords favorable dipolar/interfacial polarization,conduction loss,multiple reflection and scattering.Impressively,with an ultralow filler loading of 5 wt.%,the resultant Ni@NPC/paraffin composite achieves an excellent MA performance with a minimum reflection loss of as high as-72.4 dB and a broad absorption bandwidth of 5.0 GHz.This capability outperforms most current magnetic-dielectric hybrids counterparts.Furthermore,the MA capacity can be easily tuned with adjustments in thickness,content and type of magnetic material.Thus,this work opens up new avenues for the development of high-performance and lightweight MA materials.

Core-shell Ni_(3)Sn_(2)@C particles anchore d on 3D N-dope d porous carbon skeleton for modulated electromagnetic wave absorption

Synthesizing multi-component composites via a straightforward,reliable,and scalable approach has been challenging.Herein,a three-dimensional nitrogen-doped porous carbon decorated with core-shell Ni_(3)Sn_(2)@carbon particles(3D N-PC/Ni_(3)Sn_(2)@C)was customized through a simple salt-template pyrolysis approach.The formed Ni_(3)Sn_(2) particles are perfectly surrounded by crystalline carbon layers and em-bedded in 3D carbon walls during pyrolysis.The dual protection of crystalline carbon layers and porous carbon walls guarantees the electrical conductivity and stability of Ni_(3)Sn_(2).The intriguing 3D and core-shell structure coupled with the introduction of multiple components empowers the composite with rich heterogeneous interface and conductive network,and contributes to the lightweight,corrosion resistance,oxidation resistance,and superior stability of electromagnetic(EM)wave absorbers.The N-PC/Ni_(3)Sn_(2)@C possesses the minimum reflection loss(RL min)of-54.01 dB and wide effective absorption bandwidth(EAB)of 7.36 GHz under a low filler content of less than 10%.The concept in the work proposes a facile,eco-friendly,and scalable pathway for the synthesis of other heterogeneous structures of EM wave ab-sorbers.

Pomegranate micro/nano hierarchical plasma structure for superior microwave absorption

Inspired by the pomegranate natural artful structure,pomegranate micro/nano hierarchical plasma configuration of Fe/Fe3C@graphitized carbon(FFC/pCL)was constructed based on the green sol-gel method and in-situ chemical vapor deposition(CVD)synthesis protocol.Pomegranate-like FFC/pCL successfully overcame the agglomeration phenomenon of magnetic nanoparticles with each seed of the pomegranate consisting of Fe/Fe_(3)C as cores and graphitized carbon layers as shells.The high-density arrangement of magnetic nanoparticles and the design of pomegranate-like heterostructures lead to enhanced plasmon resonance.Thus,the pomegranate-like FFC/pCL achieved a great electromagnetic wave(EMW)absorbing performance of 6.12 GHz wide band absorption at a low mass adding of only 16.7 wt.%.Such excellent EMW performance can be attributed to its unique pomegranate hierarchical plasma configuration with separated nanoscale iron cores,surface porous texture,and good carbon conductive network.This investigation provides a new paradigm for the development of magnetic/carbon based EMW absorbing materials by taking advantage of pomegranate hierarchical plasma configuration.