Wearable devices with efficient thermal management and electromagnetic interference(EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers(CF) @ po...Wearable devices with efficient thermal management and electromagnetic interference(EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers(CF) @ polyaniline(PANI)/silver nanowires(Ag NWs) composites with a “branch-trunk” interlocked micro/nanostructure were achieved through "three-in-one" multi-scale design. The reasonable assembly of the three kinds of one-dimensional(1D) materials can fully exert their excellent properties i.e., the superior flexibility of CF, the robustness of PANI, and the splendid conductivity of Ag NWs. Consequently, the constructed flexible composite demonstrates enhanced mechanical properties with a tensile stress of 1.2 MPa, which was almost 6 times that of the original material. This is mainly attributed to the fact that the PNAI(branch) was firmly attached to the CF(trunk) through polydopamine(PDA), forming a robust interlocked structure. Meanwhile, the composite possesses excellent thermal insulation and heat preservation capacity owing to the synergistically low thermal conductivity and emissivity. More importantly, the conductive path of the composite established by the three 1D materials greatly improved its EMI shielding property and Joule heating performance at low applied voltage. This work paves the way for rational utilization of the intrinsic properties of 1D materials, as well as provides a promising strategy for designing wearable electromagnetic protection and thermal energy management devices.展开更多
Developing ultrabroad radar-infrared compatible stealth materials has turned into a research hotspot,which is still a problem to be solved.Herein,the copper sulfide wrapped by reduced graphene oxide to obtain three-di...Developing ultrabroad radar-infrared compatible stealth materials has turned into a research hotspot,which is still a problem to be solved.Herein,the copper sulfide wrapped by reduced graphene oxide to obtain three-dimensional(3D)porous network composite aerogels(CuS@rGO)were synthesized via thermal reduction ways(hydrothermal,ascorbic acid reduction)and freeze-drying strategy.It was discovered that the phase components(rGO and CuS phases)and micro/nano structure(microporous and nanosheet)were well-modified by modulating the additive amounts of CuS and changing the reduction ways,which resulted in the variation of the pore structure,defects,complex permittivity,microwave absorption,radar cross section(RCS)reduction value and infrared(IR)emissivity.Notably,the obtained CuS@rGO aerogels with a single dielectric loss type can achieve an ultrabroad bandwidth of 8.44 GHz at 2.8 mm with the low filler content of 6 wt%by a hydrothermal method.Besides,the composite aerogel via the ascorbic acid reduction realizes the minimum reflection loss(RL_(min))of−60.3 dB with the lower filler content of 2 wt%.The RCS reduction value can reach 53.3 dB m^(2),which effectively reduces the probability of the target being detected by the radar detector.Furthermore,the laminated porous architecture and multicomponent endowed composite aerogels with thermal insulation and IR stealth versatility.Thus,this work offers a facile method to design and develop porous rGO-based composite aerogel absorbers with radar-IR compatible stealth.展开更多
Alkali and Co^(2+)co-modulation has seldom been investigated as a prospective strategy to achieve high-efficient microwave absorbing(MA)materials.In this work,a new alkali and Co ion exchange co-modulation strategy wa...Alkali and Co^(2+)co-modulation has seldom been investigated as a prospective strategy to achieve high-efficient microwave absorbing(MA)materials.In this work,a new alkali and Co ion exchange co-modulation strategy was first reported,leading to broadband MA capacity through simultaneous manipulating multiple factors,such as composition,micromorphology,and heterogeneous interface.And enhancements in impedance matching and magnetic-dielectric loss were synergistically realized.Consequently,the optimized FeCo alloy@porous carbon(FPC)nanocomposite with the alkali regulation delivered an effective absorption bandwidth(EAB)of 6.72 GHz,making it the merely single FeCo-based metal-organic framework derived FPC absorber with a low filler content of 15 wt.%.Interestingly,the nanocomposites by ion exchange strategy realized the switchable“on/off”states on electromagnetic response.Furthermore,the radar cross-section(RCS)reduction value of the products reached 25.6 dB·m^(2) under the incident angle of 0°.In brief,this work not only offers the special role of alkali and Co^(2+)co-modulation in composition regulation,structure design,and MA capacity,but also provides a reliable strategy to develop smart nano-absorbers to cope with electromagnetic pollution issues.展开更多
Nanocomposites with heterogeneous structures and magneto-electric synergistic losses have broad prospects for improving electromagnetic wave(EMW)absorption performance.In this study,we synthesized Co_(2)NiO_(4)@MnCo_(...Nanocomposites with heterogeneous structures and magneto-electric synergistic losses have broad prospects for improving electromagnetic wave(EMW)absorption performance.In this study,we synthesized Co_(2)NiO_(4)@MnCo_(2)O_(4.5)nanoparticles with abundant hetero-interfaces and multiple magnetoelectric loss mechanisms by a facile hydrothermal method.The excess 0.5 oxygen atoms in MnCo_(2)O_(4.5) produce more vacancies and contribute to the enhancement of electrical conductivity.Sequential nanoneedle clusters facilitate multiple reflections and absorption of EMW in the materials,which are accompanied by an abundance of heterogeneous interfaces to improve the dielectric loss.The Co_(2)NiO_(4)@MnCo_(2)O_(4.5)composites showed a minimum reflection loss(RLmin)of30.01 dB and a superior effective absorption bandwidth(EAB)of 6.12 GHz(11.88 GHze18 GHz)at a thickness of 2.00 mm.Computer Simulation Technology(CST)revealed that the obtained particles show very low radar crosssection(RCS)values and almost full coverage angles.The maximum reduction of RCS at vertical incidence reaches 19.98 dB m2.The Co_(2)NiO_(4)@MnCo_(2)O_(4.5)nanoparticles exhibit outstanding radar attenuation properties,which can effectively inhibit the reflection and scattering of EMW.Therefore,the prepared Co_(2)NiO_(4)@MnCo_(2)O_(4.5)absorbers have great application potential in the field of EMW absorption.展开更多
Heterogeneous interface engineering is closely related to the structural design of electromagnetic absorbers;thus,the interface control through structural design is a considerable approach to optimize the electromagne...Heterogeneous interface engineering is closely related to the structural design of electromagnetic absorbers;thus,the interface control through structural design is a considerable approach to optimize the electromagnetic wave absorption(EWA)performance.Herein,the 3D hierarchical structure composites composed of two-dimensional reduced graphite oxide(rGO)and hollow raspberry Fe_(3)O_(4) nanoparticles was successfully fabricated by a simple pyrolysis and self-assembly process.This specific structure enriches the characteristics of interface polarization and dipole polarization,which further induces significant EWA behavior.By adjusting the amount of graphite oxide(GO),the complex dielectric constant of the obtained hybrids can be controlled,and the heterointerface can be cleverly adjusted.The minimum reflection loss(RLmin)of the typical products can be up to−73.86 dB at the thickness is only 1.35 mm,and the maximum effective absorption bandwidth(EAB)can reach 5.1 GHz.This work demonstrates that the unique structure and tunable components can fully improve the potential of electromagnetic absorption performance,which provides basic guidance for the heterogeneous interface engineering of efficient electromagnetic functional materials.展开更多
Solar interfacial evaporation has been considered as a promising method to alleviate fresh water re-sources shortage.The shortage of freshwater resources requires advanced materials that can accelerate the evaporation...Solar interfacial evaporation has been considered as a promising method to alleviate fresh water re-sources shortage.The shortage of freshwater resources requires advanced materials that can accelerate the evaporation of water by the sun.However,the simple structure of photothermal materials are vitally restricted by finite light absorption.Herein,this work presents a strategy for the synthesis of a spinel-type micro-nano hierarchical tower structure solar absorbent(Mn_(0.6)Ni_(1.4)Co_(2)O_(y))with the low forbidden band(=1.56 eV)and high absorption(97.88%).The products show great potential in solar-thermal energy conversion by creating a trapping effect.The prepared solar absorbent and epoxy resin are evenly mixed and then fully immersed in polyurethane(PU)sponge for water evaporation.The hydrophilic and porous Mn_(0.6)Ni_(1.4)Co_(2)O_(y)@PU sponge can quickly deliver water upwards,suppress the heat loss,and concentrate the absorbed heat on the evaporation of water.The products exhibited an excellent evaporation rate of 2.261 kg m^(-2) h^(-1) and an impressive evaporation efficiency of 156%under a single sun exposure.Besides,the samples also can maintain the stability and recycling performance for a long time.These findings show that Mn_(0.6)Ni_(1.4)Co_(2)O_(y) have great application prospects in the solar interfacial evaporation.展开更多
基金supported by the National Nature Science Foundation of China (Nos. 51971111, 52273247)the facilities in the Center for Microscopy and Analysis at Nanjing University of Aeronautics and Astronautics and the Fund of Prospective Layout of Scientific Research for NUAA (Nanjing University of Aeronautics and Astronautics (No. ILA220461A22)。
文摘Wearable devices with efficient thermal management and electromagnetic interference(EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers(CF) @ polyaniline(PANI)/silver nanowires(Ag NWs) composites with a “branch-trunk” interlocked micro/nanostructure were achieved through "three-in-one" multi-scale design. The reasonable assembly of the three kinds of one-dimensional(1D) materials can fully exert their excellent properties i.e., the superior flexibility of CF, the robustness of PANI, and the splendid conductivity of Ag NWs. Consequently, the constructed flexible composite demonstrates enhanced mechanical properties with a tensile stress of 1.2 MPa, which was almost 6 times that of the original material. This is mainly attributed to the fact that the PNAI(branch) was firmly attached to the CF(trunk) through polydopamine(PDA), forming a robust interlocked structure. Meanwhile, the composite possesses excellent thermal insulation and heat preservation capacity owing to the synergistically low thermal conductivity and emissivity. More importantly, the conductive path of the composite established by the three 1D materials greatly improved its EMI shielding property and Joule heating performance at low applied voltage. This work paves the way for rational utilization of the intrinsic properties of 1D materials, as well as provides a promising strategy for designing wearable electromagnetic protection and thermal energy management devices.
基金financial support from the National Nature Science Foundation of China(No.51971111).
文摘Developing ultrabroad radar-infrared compatible stealth materials has turned into a research hotspot,which is still a problem to be solved.Herein,the copper sulfide wrapped by reduced graphene oxide to obtain three-dimensional(3D)porous network composite aerogels(CuS@rGO)were synthesized via thermal reduction ways(hydrothermal,ascorbic acid reduction)and freeze-drying strategy.It was discovered that the phase components(rGO and CuS phases)and micro/nano structure(microporous and nanosheet)were well-modified by modulating the additive amounts of CuS and changing the reduction ways,which resulted in the variation of the pore structure,defects,complex permittivity,microwave absorption,radar cross section(RCS)reduction value and infrared(IR)emissivity.Notably,the obtained CuS@rGO aerogels with a single dielectric loss type can achieve an ultrabroad bandwidth of 8.44 GHz at 2.8 mm with the low filler content of 6 wt%by a hydrothermal method.Besides,the composite aerogel via the ascorbic acid reduction realizes the minimum reflection loss(RL_(min))of−60.3 dB with the lower filler content of 2 wt%.The RCS reduction value can reach 53.3 dB m^(2),which effectively reduces the probability of the target being detected by the radar detector.Furthermore,the laminated porous architecture and multicomponent endowed composite aerogels with thermal insulation and IR stealth versatility.Thus,this work offers a facile method to design and develop porous rGO-based composite aerogel absorbers with radar-IR compatible stealth.
基金We are thankful for financial support from the National Nature Science Foundation of China(Nos.51971111 and 52273247)the Fund of Prospective Layout of Scientific Research for NUAA(Nanjing University of Aeronautics and Astronautics)(No.ILA220461A22)the facilities in the Center for Microscopy and Analysis at Nanjing University of Aeronautics and Astronautics.
文摘Alkali and Co^(2+)co-modulation has seldom been investigated as a prospective strategy to achieve high-efficient microwave absorbing(MA)materials.In this work,a new alkali and Co ion exchange co-modulation strategy was first reported,leading to broadband MA capacity through simultaneous manipulating multiple factors,such as composition,micromorphology,and heterogeneous interface.And enhancements in impedance matching and magnetic-dielectric loss were synergistically realized.Consequently,the optimized FeCo alloy@porous carbon(FPC)nanocomposite with the alkali regulation delivered an effective absorption bandwidth(EAB)of 6.72 GHz,making it the merely single FeCo-based metal-organic framework derived FPC absorber with a low filler content of 15 wt.%.Interestingly,the nanocomposites by ion exchange strategy realized the switchable“on/off”states on electromagnetic response.Furthermore,the radar cross-section(RCS)reduction value of the products reached 25.6 dB·m^(2) under the incident angle of 0°.In brief,this work not only offers the special role of alkali and Co^(2+)co-modulation in composition regulation,structure design,and MA capacity,but also provides a reliable strategy to develop smart nano-absorbers to cope with electromagnetic pollution issues.
基金We are thankful to the financial support from the National Natural Science Foundation of China(grant No.51971111)Innovation Project of Nanjing University of Aeronautics and Astronautics(grant No.xcxjh20210604)。
文摘Nanocomposites with heterogeneous structures and magneto-electric synergistic losses have broad prospects for improving electromagnetic wave(EMW)absorption performance.In this study,we synthesized Co_(2)NiO_(4)@MnCo_(2)O_(4.5)nanoparticles with abundant hetero-interfaces and multiple magnetoelectric loss mechanisms by a facile hydrothermal method.The excess 0.5 oxygen atoms in MnCo_(2)O_(4.5) produce more vacancies and contribute to the enhancement of electrical conductivity.Sequential nanoneedle clusters facilitate multiple reflections and absorption of EMW in the materials,which are accompanied by an abundance of heterogeneous interfaces to improve the dielectric loss.The Co_(2)NiO_(4)@MnCo_(2)O_(4.5)composites showed a minimum reflection loss(RLmin)of30.01 dB and a superior effective absorption bandwidth(EAB)of 6.12 GHz(11.88 GHze18 GHz)at a thickness of 2.00 mm.Computer Simulation Technology(CST)revealed that the obtained particles show very low radar crosssection(RCS)values and almost full coverage angles.The maximum reduction of RCS at vertical incidence reaches 19.98 dB m2.The Co_(2)NiO_(4)@MnCo_(2)O_(4.5)nanoparticles exhibit outstanding radar attenuation properties,which can effectively inhibit the reflection and scattering of EMW.Therefore,the prepared Co_(2)NiO_(4)@MnCo_(2)O_(4.5)absorbers have great application potential in the field of EMW absorption.
基金support from the National Nature Science Foundation of China(Nos.51971111 and 52273247)the Fund of Prospective Layout of Scientific Research for NUAA(Nanjing University of Aeronautics and Astronautics(No.ILA220461A22).
文摘Heterogeneous interface engineering is closely related to the structural design of electromagnetic absorbers;thus,the interface control through structural design is a considerable approach to optimize the electromagnetic wave absorption(EWA)performance.Herein,the 3D hierarchical structure composites composed of two-dimensional reduced graphite oxide(rGO)and hollow raspberry Fe_(3)O_(4) nanoparticles was successfully fabricated by a simple pyrolysis and self-assembly process.This specific structure enriches the characteristics of interface polarization and dipole polarization,which further induces significant EWA behavior.By adjusting the amount of graphite oxide(GO),the complex dielectric constant of the obtained hybrids can be controlled,and the heterointerface can be cleverly adjusted.The minimum reflection loss(RLmin)of the typical products can be up to−73.86 dB at the thickness is only 1.35 mm,and the maximum effective absorption bandwidth(EAB)can reach 5.1 GHz.This work demonstrates that the unique structure and tunable components can fully improve the potential of electromagnetic absorption performance,which provides basic guidance for the heterogeneous interface engineering of efficient electromagnetic functional materials.
基金financially supported by the National Science Foundation of China(Nos.51971111 and52273247)the Innovation Project of Nanjing University of Aeronautics and Astronautics(No.xcxjh20210604).
文摘Solar interfacial evaporation has been considered as a promising method to alleviate fresh water re-sources shortage.The shortage of freshwater resources requires advanced materials that can accelerate the evaporation of water by the sun.However,the simple structure of photothermal materials are vitally restricted by finite light absorption.Herein,this work presents a strategy for the synthesis of a spinel-type micro-nano hierarchical tower structure solar absorbent(Mn_(0.6)Ni_(1.4)Co_(2)O_(y))with the low forbidden band(=1.56 eV)and high absorption(97.88%).The products show great potential in solar-thermal energy conversion by creating a trapping effect.The prepared solar absorbent and epoxy resin are evenly mixed and then fully immersed in polyurethane(PU)sponge for water evaporation.The hydrophilic and porous Mn_(0.6)Ni_(1.4)Co_(2)O_(y)@PU sponge can quickly deliver water upwards,suppress the heat loss,and concentrate the absorbed heat on the evaporation of water.The products exhibited an excellent evaporation rate of 2.261 kg m^(-2) h^(-1) and an impressive evaporation efficiency of 156%under a single sun exposure.Besides,the samples also can maintain the stability and recycling performance for a long time.These findings show that Mn_(0.6)Ni_(1.4)Co_(2)O_(y) have great application prospects in the solar interfacial evaporation.
