The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem.Ternary MXene/ANF(ar...The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem.Ternary MXene/ANF(aramid nanofibers)–MoS_(2)composite films with nacre-like layered structure here are fabricated after the introduction of MoS_(2)into binary MXene/ANF composite system.The introduction of MoS_(2)fulfills an impressive“kill three birds with one stone”improvement effect:lubrication toughening mechanical performance,reduction in secondary reflection pollution of electromagnetic wave,and improvement in the performance of photothermal conversion.After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 50:50),the strain to failure and tensile strength increase from 22.1±1.7%and 105.7±6.4 MPa and to 25.8±0.7%and 167.3±9.1 MPa,respectively.The toughness elevates from 13.0±4.1 to 26.3±0.8 MJ m^(−3)(~102.3%)simultaneously.And the reflection shielding effectiveness(SE_(R))of MXene/ANF(mass ratio of 50:50)decreases~10.8%.EMI shielding effectiveness(EMI SE)elevates to 41.0 dB(8.2–12.4 GHz);After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 60:40),the strain to failure increases from 18.3±1.9%to 28.1±0.7%(~53.5%),the SE_(R)decreases~22.2%,and the corresponding EMI SE is 43.9 dB.The MoS_(2)also leads to a more efficient photothermal conversion performance(~45 to~55℃).Additionally,MXene/ANF–MoS_(2)composite films exhibit excellent electric heating performance,quick temperature elevation(15 s),excellent cycle stability(2,2.5,and 3 V),and long-term stability(2520 s).Combining with excellent mechanical performance with high MXene content,electric heating performance,and photothermal conversion performance,EMI shielding ternary MXene/ANF–MoS_(2)composite films could be applied in many industrial areas.This work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers.展开更多
Currently,the develop-ment of low-reflection electromagnetic interference(EMI)shielding composite materials for mitigating secondary electromagnetic wave pollution has become a major research focus.However,achieving t...Currently,the develop-ment of low-reflection electromagnetic interference(EMI)shielding composite materials for mitigating secondary electromagnetic wave pollution has become a major research focus.However,achieving thinness,high toughness,low reflectivity,and multi-functionality in flexible EMI shielding films remains a challenge.To address this issue,this study introduces a“magnetic-electric”Janus structure EMI shielding composite film composed of MXene nanosheets,carbonized ZIF-67(CZIF67)nanop-articles and aramid nanofibers(ANF),balancing thinness,high toughness,low reflectivity,and multifunctionality.As a result,the MXene/ANF-CZIF67/ANF-4(MACA-4)sample exhibits high tensile strength(110.0±7.0 MPa),large strain tolerance(21%),and superior toughness(14.9±0.9 MJ·m^(-3)),reflecting the stress dispersion effect of the three-dimensional(3D)network structure of ANF and the strengthening effect of hydrogen bonding.The sample exhibits excellent flexibility,resistance to rubbing and folding.Even with a thickness of only 80μm,the MACA-4 film exhibits a reflection performance(SER)as low as 4.3 to 4.5 dB in the 8.2 to 9.6 GHz band and the SE_(T)in the X-band reaches 44.8 dB.In addition,the superior conductivity of the MXene/ANF layer and the localized surface plasmon resonance effect give the MACA composite films excellent electrothermal conversion capabilities.Surprisingly,the sample also exhibited excellent infrared stealth and fire alarm properties.This work offers valuable guidance on the fabrication of ultra-thin flexible EMI shielding composites and provides an important scientific basis for the design and application of efficient EMI shielding materials.展开更多
Electromagnetic wave radiation disrupts electronic devices and threatens human health.Microwave absorbing materials are essential for addressing electromagnetic pollution and military stealth applications.Advancement ...Electromagnetic wave radiation disrupts electronic devices and threatens human health.Microwave absorbing materials are essential for addressing electromagnetic pollution and military stealth applications.Advancement of electronics creates demand for absorbers with thin thickness,light weight,wide bandwidth,and strong absorption.Conventional materials suffer from poor impedance matching and limited loss mechanisms in the Ku band.Heterojunction engineering offers solutions through control of band alignment and charge distribution.The built-in electric field serves as a core mechanism for enhancing dielectric loss.However,limitations exist in understanding of formation mechanisms of built-in electric fields in multi-interface systems.This study develops a ZnNiCo-LDH/MXene composite with coral-inspired architecture.Construction of high-density Mott-Schottky interfaces occurs through electrostatic assembly of polar semiconductor units and conductive matrices.Vertical growth of flower-like layered double hydroxide(LDH)on MXene extends propagation paths of electromagnetic waves.This design creates continuous networks of built-in electric fields.Enhanced charge separation and interfacial polarization result.Performance demonstrates−49.6 dB reflection loss at 1.35 mm thickness.Effective bandwidth reaches 3.4 GHz across Ku-band frequencies.Radar cross-section simulations confirm−39.57 dB·m^(2) signal suppression.These achievements meet requirements of advanced absorbers.The work establishes a new paradigm for manipulation of built-in electric fields through multi-interface engineering.展开更多
基金supported by the Talent Fund of Beijing Jiaotong University(No,2023XKRC015)the National Natural Science Foundation of China(Nos.52172081,52073010 and 52373259).
文摘The design and fabrication of high toughness electromagnetic interference(EMI)shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem.Ternary MXene/ANF(aramid nanofibers)–MoS_(2)composite films with nacre-like layered structure here are fabricated after the introduction of MoS_(2)into binary MXene/ANF composite system.The introduction of MoS_(2)fulfills an impressive“kill three birds with one stone”improvement effect:lubrication toughening mechanical performance,reduction in secondary reflection pollution of electromagnetic wave,and improvement in the performance of photothermal conversion.After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 50:50),the strain to failure and tensile strength increase from 22.1±1.7%and 105.7±6.4 MPa and to 25.8±0.7%and 167.3±9.1 MPa,respectively.The toughness elevates from 13.0±4.1 to 26.3±0.8 MJ m^(−3)(~102.3%)simultaneously.And the reflection shielding effectiveness(SE_(R))of MXene/ANF(mass ratio of 50:50)decreases~10.8%.EMI shielding effectiveness(EMI SE)elevates to 41.0 dB(8.2–12.4 GHz);After the introduction of MoS_(2)into binary MXene/ANF(mass ratio of 60:40),the strain to failure increases from 18.3±1.9%to 28.1±0.7%(~53.5%),the SE_(R)decreases~22.2%,and the corresponding EMI SE is 43.9 dB.The MoS_(2)also leads to a more efficient photothermal conversion performance(~45 to~55℃).Additionally,MXene/ANF–MoS_(2)composite films exhibit excellent electric heating performance,quick temperature elevation(15 s),excellent cycle stability(2,2.5,and 3 V),and long-term stability(2520 s).Combining with excellent mechanical performance with high MXene content,electric heating performance,and photothermal conversion performance,EMI shielding ternary MXene/ANF–MoS_(2)composite films could be applied in many industrial areas.This work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers.
基金supported by the Talent Fund of Beijing Jiaotong University(No.2023XKRC015)the National Natural Science Foundation of China(No.52172081)+2 种基金the Key R&D and Promotion Special Projects(Science and Technology)of Henan Province(No.232102240068)the Henan Provincial Department of Education(No.22B150010)Henan Province Key Research and Development Project(No.251111321500).
文摘Currently,the develop-ment of low-reflection electromagnetic interference(EMI)shielding composite materials for mitigating secondary electromagnetic wave pollution has become a major research focus.However,achieving thinness,high toughness,low reflectivity,and multi-functionality in flexible EMI shielding films remains a challenge.To address this issue,this study introduces a“magnetic-electric”Janus structure EMI shielding composite film composed of MXene nanosheets,carbonized ZIF-67(CZIF67)nanop-articles and aramid nanofibers(ANF),balancing thinness,high toughness,low reflectivity,and multifunctionality.As a result,the MXene/ANF-CZIF67/ANF-4(MACA-4)sample exhibits high tensile strength(110.0±7.0 MPa),large strain tolerance(21%),and superior toughness(14.9±0.9 MJ·m^(-3)),reflecting the stress dispersion effect of the three-dimensional(3D)network structure of ANF and the strengthening effect of hydrogen bonding.The sample exhibits excellent flexibility,resistance to rubbing and folding.Even with a thickness of only 80μm,the MACA-4 film exhibits a reflection performance(SER)as low as 4.3 to 4.5 dB in the 8.2 to 9.6 GHz band and the SE_(T)in the X-band reaches 44.8 dB.In addition,the superior conductivity of the MXene/ANF layer and the localized surface plasmon resonance effect give the MACA composite films excellent electrothermal conversion capabilities.Surprisingly,the sample also exhibited excellent infrared stealth and fire alarm properties.This work offers valuable guidance on the fabrication of ultra-thin flexible EMI shielding composites and provides an important scientific basis for the design and application of efficient EMI shielding materials.
基金supported by the Fundamental Research Funds for the Central Universities(No.2025YJS170)the National Natural Science Foundation of China(No.52172081)The authors would like to thank Shiyanjia Lab(www.shiyanjia.com)for the XPS characterizations.
文摘Electromagnetic wave radiation disrupts electronic devices and threatens human health.Microwave absorbing materials are essential for addressing electromagnetic pollution and military stealth applications.Advancement of electronics creates demand for absorbers with thin thickness,light weight,wide bandwidth,and strong absorption.Conventional materials suffer from poor impedance matching and limited loss mechanisms in the Ku band.Heterojunction engineering offers solutions through control of band alignment and charge distribution.The built-in electric field serves as a core mechanism for enhancing dielectric loss.However,limitations exist in understanding of formation mechanisms of built-in electric fields in multi-interface systems.This study develops a ZnNiCo-LDH/MXene composite with coral-inspired architecture.Construction of high-density Mott-Schottky interfaces occurs through electrostatic assembly of polar semiconductor units and conductive matrices.Vertical growth of flower-like layered double hydroxide(LDH)on MXene extends propagation paths of electromagnetic waves.This design creates continuous networks of built-in electric fields.Enhanced charge separation and interfacial polarization result.Performance demonstrates−49.6 dB reflection loss at 1.35 mm thickness.Effective bandwidth reaches 3.4 GHz across Ku-band frequencies.Radar cross-section simulations confirm−39.57 dB·m^(2) signal suppression.These achievements meet requirements of advanced absorbers.The work establishes a new paradigm for manipulation of built-in electric fields through multi-interface engineering.
