Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for ...Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for applications in extreme environments,however,the integration of multiple functions in their preparation is extremely challenging.To tackle these challenges,we fabricated a multifunctional SiC@SiO_(2) nanofiber aerogel(SiC@SiO_(2) NFA)with a threedimensional(3D)porous cross-linked structure through a simple chemical vapor deposition method and subsequent heat-treatment process.The as-prepared SiC@SiO_(2) NFA exhibits an ultralow density(~11 mg cm^(-3)),ultra-elastic,fatigue-resistant and refractory performance,high temperature thermal stability,thermal insulation properties,and significant strain-dependent piezoresistive sensing behavior.Furthermore,the SiC@SiO_(2) NFA shows a superior electromagnetic wave absorption performance with a minimum refection loss(RL_(min))value of-50.36 d B and a maximum effective absorption bandwidth(EAB_(max))of 8.6 GHz.The successful preparation of this multifunctional aerogel material provides a promising prospect for the design and fabrication of the cutting-edge ceramic materials.展开更多
Multifunctionalization is the development direction of personal thermal energy regulation equipment in the future.However,it is still a huge challenge to effectively integrate multiple functionalities into one materia...Multifunctionalization is the development direction of personal thermal energy regulation equipment in the future.However,it is still a huge challenge to effectively integrate multiple functionalities into one material.In this study,a simple thermochemical process was used to prepare a multifunctional SiC nanofiber aerogel spring(SiC NFAS),which exhibited ultralow density(9 mg/cm3),ultralow thermal conductivity(0.029 W/(m·K)at 20℃),excellent ablation and oxidation resistance,and a stable three-dimensional(3D)structure that composed of a large number of interlacing 3C-SiC nanofibers with diameters of 300–500 nm and lengths in tens to hundreds of microns.Furthermore,the as-prepared SiC NFAS displayed excellent mechanical properties,with a permanent deformation of only 1.3%at 20℃after 1000 cycles.Remarkably,the SiC NFAS exhibited robust hyperelasticity and cyclic fatigue resistance at both low(~-196℃)and high(~700℃)temperatures.Due to its exceptional thermal insulation performance,the SiC NFAS can be used for personal thermal energy regulation.The results of the study conclusively show that the SiC NFAS is a multifunctional material and has potential insulation applications in both low-and high-temperature environments.展开更多
Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric const...Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric constant of Ti_(3)C_(2)T_(x)MXene,we have successfully synthesized core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres.This architecture,comprising SiO_(2) as the core,MXene as the intermediate layer,and MoS_(2) as the outer shell,is achieved through an electrostatic self‐assembly method combined with a hydrothermal process.This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS_(2) nanosheets.Notably,the synergistic combination of SiO_(2) and MoS_(2) with highly conductive MXene enables the suitable dielectric constant of the composites,ensuring optimal impedance matching.Therefore,the core‐shell structured SiO_(2)@MXene@MoS_(2) nanospheres exhibit excellent EMW absorption performance,featuring a remarkable minimum reflection loss(RL_(min))of−52.11 dB(2.4 mm).It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth(EAB)of 6.72 GHz.This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by“wide bandwidth and strong reflection loss.”展开更多
基金financially supported by the National Natural Science Foundation of China(No.U2004177 and U21A2064)Outstanding Youth Fund of Henan Province(No.212300410081)+1 种基金Scientific and Technological Innovation Talents in Colleges and Universities in Henan Province(22HASTIT001)The Research and Entrepreneurship Start-up Projects for Overseas Returned Talents。
文摘Traditional ceramic materials are generally brittle and not flexible with high production costs,which seriously hinders their practical applications.Multifunctional nanofiber ceramic aerogels are highly desirable for applications in extreme environments,however,the integration of multiple functions in their preparation is extremely challenging.To tackle these challenges,we fabricated a multifunctional SiC@SiO_(2) nanofiber aerogel(SiC@SiO_(2) NFA)with a threedimensional(3D)porous cross-linked structure through a simple chemical vapor deposition method and subsequent heat-treatment process.The as-prepared SiC@SiO_(2) NFA exhibits an ultralow density(~11 mg cm^(-3)),ultra-elastic,fatigue-resistant and refractory performance,high temperature thermal stability,thermal insulation properties,and significant strain-dependent piezoresistive sensing behavior.Furthermore,the SiC@SiO_(2) NFA shows a superior electromagnetic wave absorption performance with a minimum refection loss(RL_(min))value of-50.36 d B and a maximum effective absorption bandwidth(EAB_(max))of 8.6 GHz.The successful preparation of this multifunctional aerogel material provides a promising prospect for the design and fabrication of the cutting-edge ceramic materials.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.U2004177 and U21A2064)Outstanding Youth Fund of the National Science Fundation of Henan Province(No.212300410081).
文摘Multifunctionalization is the development direction of personal thermal energy regulation equipment in the future.However,it is still a huge challenge to effectively integrate multiple functionalities into one material.In this study,a simple thermochemical process was used to prepare a multifunctional SiC nanofiber aerogel spring(SiC NFAS),which exhibited ultralow density(9 mg/cm3),ultralow thermal conductivity(0.029 W/(m·K)at 20℃),excellent ablation and oxidation resistance,and a stable three-dimensional(3D)structure that composed of a large number of interlacing 3C-SiC nanofibers with diameters of 300–500 nm and lengths in tens to hundreds of microns.Furthermore,the as-prepared SiC NFAS displayed excellent mechanical properties,with a permanent deformation of only 1.3%at 20℃after 1000 cycles.Remarkably,the SiC NFAS exhibited robust hyperelasticity and cyclic fatigue resistance at both low(~-196℃)and high(~700℃)temperatures.Due to its exceptional thermal insulation performance,the SiC NFAS can be used for personal thermal energy regulation.The results of the study conclusively show that the SiC NFAS is a multifunctional material and has potential insulation applications in both low-and high-temperature environments.
基金Joint Fund of Research and Development Program of Henan Province,Grant/Award Number:222301420002National Natural Science Foundation of China,Grant/Award Number:U21A2064Scientific and Technological Innovation Talents in Colleges and Universities in Henan Province,Grant/Award Number:22HASTIT001。
文摘Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric constant of Ti_(3)C_(2)T_(x)MXene,we have successfully synthesized core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres.This architecture,comprising SiO_(2) as the core,MXene as the intermediate layer,and MoS_(2) as the outer shell,is achieved through an electrostatic self‐assembly method combined with a hydrothermal process.This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS_(2) nanosheets.Notably,the synergistic combination of SiO_(2) and MoS_(2) with highly conductive MXene enables the suitable dielectric constant of the composites,ensuring optimal impedance matching.Therefore,the core‐shell structured SiO_(2)@MXene@MoS_(2) nanospheres exhibit excellent EMW absorption performance,featuring a remarkable minimum reflection loss(RL_(min))of−52.11 dB(2.4 mm).It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth(EAB)of 6.72 GHz.This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by“wide bandwidth and strong reflection loss.”
