With the rapid advancement of the intelligent era, intelligent electromagnetic interference (EMI) shielding devices are receiving more and more attention due to their advantages in environmental self-adaption response...With the rapid advancement of the intelligent era, intelligent electromagnetic interference (EMI) shielding devices are receiving more and more attention due to their advantages in environmental self-adaption response. Accordingly, appropriate EMI shielding materials are crucial to blocking harmful electromagnetic radiation and passing serviceable electromagnetic waves. Smart EMI shielding materials that can dynamically adjust their EMI shielding effectiveness (SE) in response to specific application requirements and environmental changes are extremely advantageous in both military and civil areas. To date, materials with adjustable EMI SE for various responses have been developed. This review pays special attention to smart materials with tunable EMI SE. The design strategies, mechanism and recent progress of smart EMI shielding materials are discussed together with different stimuli responses, including compression strain, tensile strain, chemical reagent, shape memory, phase transition and crossover angle change-induced responses. The review ends up to discuss challenges and perspectives for smart EMI shielding materials.展开更多
With the escalating concerns over environmental pollution,effective management of industrial waste has emerged as a critical research focus in modern materials science.In this study,we developed cobalt-cobalt oxide do...With the escalating concerns over environmental pollution,effective management of industrial waste has emerged as a critical research focus in modern materials science.In this study,we developed cobalt-cobalt oxide doped lignin-based porous carbon materials(Co@CoO@MPC)by employing zeolitic imidazolate framework-67(ZIF-67)decorated with industrial black powder-a byproduct rich in lignin and carbon.The synthesis involved potassium hydroxide(KOH)-assisted microwave activation,which enabled the creation of a porous structure,thereby markedly increasing the specific surface area and interfacial properties of the composites.During pyrolysis,ZIF-67 underwent transformation into cobalt(Co)and cobalt oxide(CoO)phases.The synergistic interaction between Co/CoO and the porous carbon significantly enhanced microwave absorption through both dielectric and magnetic loss mechanisms.The Co@CoO@MPC composites demonstrated exceptional microwave absorption properties across a broad frequency range,particularly at higher frequencies.Specifically,the sample after 2-min microwave irradiation exhibits a high EAB value of 5.7 GHz(1.6 mm thickness)and an RL_(min) value of−30 dB(2.0 mm thickness).This research not only offers an innovative approach to recovering resources from industrial black powder but also provides groundbreaking strategies for developing high-performance microwave-absorbing materials.展开更多
Plastic waste recycling is a focal point in today's sustainable development efforts.Improper disposal can lead to secondary pollution,posing threats to the environment and human health.In this study,we aim to recy...Plastic waste recycling is a focal point in today's sustainable development efforts.Improper disposal can lead to secondary pollution,posing threats to the environment and human health.In this study,we aim to recycle waste epoxy resin and glass fiber-reinforced epoxy resin composites via an electroless plating and a carbonization process,to design high-value-added carbon materials for microwave absorption.By pulverizing solid waste and introducing magnetic metal nanoparticles onto its surface,a composite carbon material capable of excellent microwave absorption performance was successfully developed.Specifically,doping nickel particles into carbon materials derived from glass fiber/epoxy resin achieved a wide effective absorption bandwidth(EAB)of 5.9 GHz with a matching thickness of 1.9 mm,covering nearly the entire Ku band,and achieving a minimum reflection loss(RLmin)of−36 dB simultaneously.The superior absorption performance is attributed to multiple reflections or scattering of electromagnetic waves within the material,as well as conduction and magnetic losses,dipole and interfacial polarization effects.These results demonstrate that through rational design and optimization,waste epoxy and waste glass fiber-reinforced epoxy resin-based composite materials can be effectively recycled into high-performance microwave absorbing materials,offering a straightforward and efficient pathway for waste resource utilization.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52173264)the Natural Science Foundation Project of Chongqing(No.cstc2024ycjh-bgzxm0005).
文摘With the rapid advancement of the intelligent era, intelligent electromagnetic interference (EMI) shielding devices are receiving more and more attention due to their advantages in environmental self-adaption response. Accordingly, appropriate EMI shielding materials are crucial to blocking harmful electromagnetic radiation and passing serviceable electromagnetic waves. Smart EMI shielding materials that can dynamically adjust their EMI shielding effectiveness (SE) in response to specific application requirements and environmental changes are extremely advantageous in both military and civil areas. To date, materials with adjustable EMI SE for various responses have been developed. This review pays special attention to smart materials with tunable EMI SE. The design strategies, mechanism and recent progress of smart EMI shielding materials are discussed together with different stimuli responses, including compression strain, tensile strain, chemical reagent, shape memory, phase transition and crossover angle change-induced responses. The review ends up to discuss challenges and perspectives for smart EMI shielding materials.
基金Natural Science Foundation Project of Chongqing(No.cstc2024ycjh-bgzxm0005)the Opening Project of State Key Laboratory of Solid Lubrication(No.LSL2416)+1 种基金Fundamental Research Funds for the Central Universities(No.SWUXDJH202314)Chongqing Municipal Training Program of Innovation and Entrepreneurship for Undergraduates(No.S202410635124)for financial support.
文摘With the escalating concerns over environmental pollution,effective management of industrial waste has emerged as a critical research focus in modern materials science.In this study,we developed cobalt-cobalt oxide doped lignin-based porous carbon materials(Co@CoO@MPC)by employing zeolitic imidazolate framework-67(ZIF-67)decorated with industrial black powder-a byproduct rich in lignin and carbon.The synthesis involved potassium hydroxide(KOH)-assisted microwave activation,which enabled the creation of a porous structure,thereby markedly increasing the specific surface area and interfacial properties of the composites.During pyrolysis,ZIF-67 underwent transformation into cobalt(Co)and cobalt oxide(CoO)phases.The synergistic interaction between Co/CoO and the porous carbon significantly enhanced microwave absorption through both dielectric and magnetic loss mechanisms.The Co@CoO@MPC composites demonstrated exceptional microwave absorption properties across a broad frequency range,particularly at higher frequencies.Specifically,the sample after 2-min microwave irradiation exhibits a high EAB value of 5.7 GHz(1.6 mm thickness)and an RL_(min) value of−30 dB(2.0 mm thickness).This research not only offers an innovative approach to recovering resources from industrial black powder but also provides groundbreaking strategies for developing high-performance microwave-absorbing materials.
基金supported by the National Natural Science Foundation of China(No.52173264)the Natural Science Foundation Project of Chongqing(No.cstc2024ycjh-bgzxm0005)+1 种基金the Fundamental Research Funds for the Central Universities(No.SWU-XDJH202314)The authors thanks Dr.Xi Tang in Southwest University for the technical support in the use of the vector network analyzer.
文摘Plastic waste recycling is a focal point in today's sustainable development efforts.Improper disposal can lead to secondary pollution,posing threats to the environment and human health.In this study,we aim to recycle waste epoxy resin and glass fiber-reinforced epoxy resin composites via an electroless plating and a carbonization process,to design high-value-added carbon materials for microwave absorption.By pulverizing solid waste and introducing magnetic metal nanoparticles onto its surface,a composite carbon material capable of excellent microwave absorption performance was successfully developed.Specifically,doping nickel particles into carbon materials derived from glass fiber/epoxy resin achieved a wide effective absorption bandwidth(EAB)of 5.9 GHz with a matching thickness of 1.9 mm,covering nearly the entire Ku band,and achieving a minimum reflection loss(RLmin)of−36 dB simultaneously.The superior absorption performance is attributed to multiple reflections or scattering of electromagnetic waves within the material,as well as conduction and magnetic losses,dipole and interfacial polarization effects.These results demonstrate that through rational design and optimization,waste epoxy and waste glass fiber-reinforced epoxy resin-based composite materials can be effectively recycled into high-performance microwave absorbing materials,offering a straightforward and efficient pathway for waste resource utilization.
