The rational and effective combination of multicomponent materials and ingenious microstructure design for efficient electromagnetic wave(EMW)absorption are still challenging.In this paper,MXene was used as the aeroge...The rational and effective combination of multicomponent materials and ingenious microstructure design for efficient electromagnetic wave(EMW)absorption are still challenging.In this paper,MXene was used as the aerogel matrix,modified with sea urchin-like magnetic Co/N-doped carbon@polyaniline(Co-NC@PANI),gelatin was introduced as the reinforcement phase of the aerogel backbone,and a microwave absorber with high efficiency and excellent performance was successfully prepared.The sea urchin-like Co-NC@PANI not only adjusted the impedance matching of the MXene but also introduced a magnetic loss mode into the composite.The multicomponent interfacial polarization,heterostructure,three-dimensional(3D)lightweight porous structure,and electromagnetic synergy strategy enabled the MXene-based aerogel modified by Co-NC@PANI(MCoP)to exhibit surprising EMW absorption properties.The maximum reflection loss(RL_(max))of the aerogel composite reached-62.4 dB,and the effective absorption bandwidth(EAB)reached 6.56 GHz when the loading was only 12%.In addition,through electromagnetic simulation experiments,the change in the electromagnetic field before and after EMW passed through the materials and the distribution of the volume loss density of EMW by the coaxial ring were observed.The coordinated electromagnetic balance strategy in the 3D network provides inspiration for the construction of materials and expands the research direction of lightweight and outstanding microwave absorbers.展开更多
High-performance electromagnetic(EM)wave absorbers,covalently bonded reduced graphene oxideFe_(3)O_(4) nanocomposites(rGO-Fe_(3)O_(4)),are synthesized via hydrothermal reaction,amidation reaction and reduction process...High-performance electromagnetic(EM)wave absorbers,covalently bonded reduced graphene oxideFe_(3)O_(4) nanocomposites(rGO-Fe_(3)O_(4)),are synthesized via hydrothermal reaction,amidation reaction and reduction process.The microstructure,surface element composition and morphology of rGO-Fe_(3)O_(4) nanocomposites are characterized and corresponding EM wave absorption properties are analyzed in great detail.It demonstrates that Fe_(3)O_(4) nanoparticles are successfully covalently grafted onto graphene by amide bonds.When the mass ratio of rGO and Fe_(3)O_(4) is 2:1(sample S2),the absorber exhibits the excellent EM wave absorption performance that the maximum reflection loss(RL)reaches up to-48.6 dB at 14.4 GHz,while the effective absorption bandwidth(RL<-10 dB)is 6.32 GHz(11.68-18.0 GHz)with a matching thickness of 2.1 mm.Furthermore,radar cross section(RCS)simulation calculation is also adopted to evaluate the ability of absorbers to scatter EM waves,which proves again that the absorption performance of absorber S2 is optimal.The outstanding EM wave absorption performance is attributed to the synergistic effect between dielectric and magnetic loss,good attenuation ability and excellent impedance matching.Moreover,covalent bonds considered to be carrier channels can facilitate electron migration,adjust EM parameters and then enhance EM wave absorption perfo rmance.This work provides a possible method for preparing efficient EM wave absorbers.展开更多
文摘The rational and effective combination of multicomponent materials and ingenious microstructure design for efficient electromagnetic wave(EMW)absorption are still challenging.In this paper,MXene was used as the aerogel matrix,modified with sea urchin-like magnetic Co/N-doped carbon@polyaniline(Co-NC@PANI),gelatin was introduced as the reinforcement phase of the aerogel backbone,and a microwave absorber with high efficiency and excellent performance was successfully prepared.The sea urchin-like Co-NC@PANI not only adjusted the impedance matching of the MXene but also introduced a magnetic loss mode into the composite.The multicomponent interfacial polarization,heterostructure,three-dimensional(3D)lightweight porous structure,and electromagnetic synergy strategy enabled the MXene-based aerogel modified by Co-NC@PANI(MCoP)to exhibit surprising EMW absorption properties.The maximum reflection loss(RL_(max))of the aerogel composite reached-62.4 dB,and the effective absorption bandwidth(EAB)reached 6.56 GHz when the loading was only 12%.In addition,through electromagnetic simulation experiments,the change in the electromagnetic field before and after EMW passed through the materials and the distribution of the volume loss density of EMW by the coaxial ring were observed.The coordinated electromagnetic balance strategy in the 3D network provides inspiration for the construction of materials and expands the research direction of lightweight and outstanding microwave absorbers.
基金financially supported by the National Natural Science Foundation of China(No.51672222)the Joint Fund Project-Enterprise-Shaanxi Coal Joint Fund Project(No.2019JLM-32)the Spaceflight Foundation of China(No.2014-HT-XGD)。
文摘High-performance electromagnetic(EM)wave absorbers,covalently bonded reduced graphene oxideFe_(3)O_(4) nanocomposites(rGO-Fe_(3)O_(4)),are synthesized via hydrothermal reaction,amidation reaction and reduction process.The microstructure,surface element composition and morphology of rGO-Fe_(3)O_(4) nanocomposites are characterized and corresponding EM wave absorption properties are analyzed in great detail.It demonstrates that Fe_(3)O_(4) nanoparticles are successfully covalently grafted onto graphene by amide bonds.When the mass ratio of rGO and Fe_(3)O_(4) is 2:1(sample S2),the absorber exhibits the excellent EM wave absorption performance that the maximum reflection loss(RL)reaches up to-48.6 dB at 14.4 GHz,while the effective absorption bandwidth(RL<-10 dB)is 6.32 GHz(11.68-18.0 GHz)with a matching thickness of 2.1 mm.Furthermore,radar cross section(RCS)simulation calculation is also adopted to evaluate the ability of absorbers to scatter EM waves,which proves again that the absorption performance of absorber S2 is optimal.The outstanding EM wave absorption performance is attributed to the synergistic effect between dielectric and magnetic loss,good attenuation ability and excellent impedance matching.Moreover,covalent bonds considered to be carrier channels can facilitate electron migration,adjust EM parameters and then enhance EM wave absorption perfo rmance.This work provides a possible method for preparing efficient EM wave absorbers.