The rapid development of portable electronics,wearable technologies,and healthcare monitoring systems necessitates the innovation of flexible energy storage systems.Considering environmental pollution and the depletio...The rapid development of portable electronics,wearable technologies,and healthcare monitoring systems necessitates the innovation of flexible energy storage systems.Considering environmental pollution and the depletion of fossil resources,the utilization of renewable resources to engineer advanced flexible materials has become especially crucial.Cellulose,the most abundant natural polymer,has emerged as a promising precursor for advanced functional materials due to its unique structure and properties.Typically,the easy processability,tunable chemical structure,self-assembly behavior,mechanical strength,and reinforcing capability enable its utilization as binder,substrate,hybrid electrode,separator,and electrolyte reservoir for flexible energy storage devices.This review comprehensively summarizes the design,fabrication,and mechanical and electrochemical performances of cellulose-based materials.The structure and unique properties of cellulose are first briefly introduced.Then,the construction of cellulose-based materials in the forms of 1D fibers/filaments,2D films/membranes,3D hydrogels and aerogels is discussed,and the merits of cellulose in these materials are emphasized.After that,the various advanced applications in supercapacitors,lithium-ion batteries,lithium-sulfur batteries,sodium-ion batteries,metal-air batteries,and Zn-ion batteries are presented in detail.Finally,an outlook of the potential challenges and future perspectives in advanced cellulose-based materials for flexible energy storage systems is discussed.展开更多
With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shieldin...With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role.Meanwhile,the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications.Hitherto,a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed.In this review,we not only introduce the recent development of flexible EMI shielding materials,but also elaborate the EMI shielding mechanisms and the index for"green EMI shielding"performance.In addition,the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized.Finally,we propose several possible research directions for flexible EMI shielding materials in near future,which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.展开更多
In this study, several kinds of flexible protective materials sprayed with polyurea elastomers （hereinafter referred to as polyurea elastomer protective material） were adopted to meet the abrasion resistance require...In this study, several kinds of flexible protective materials sprayed with polyurea elastomers （hereinafter referred to as polyurea elastomer protective material） were adopted to meet the abrasion resistance requirement of hydraulic structures, and their abrasion resistances against the water flow with suspended load or bed load were studied systematically through tests. Natural basalt stones were adopted as the abrasive for simulation of the abrasion effect of the water flow with bed load, and test results indicate that the basalt stone is suitable for use in the abrasion resistance test of the flexible protective material. The wear process of the polyurea elastomer protective material is stable, and the wear loss is linear with the time of abrasion. If the wear thickness is regarded as the abrasion resistance evaluation factor, the abrasion resistance of the 351 pure polyurea is about twice those of pure polyurea with a high level of hardness and aliphatic polyurea, and over five times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with suspended load. It is also about 50 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load. Overall, the abrasion resistance of pure polyurea presented a decreasing trend with increasing hardness. Pure polyurea with a Shore hardness of D30 has the best abrasion resistance, which is 60 to 70 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load, and has been recommended, among the five kinds of pure polyurea materials with different hardness, in anti-abrasion protection of hydraulic structures.展开更多
The mechanical performance of flexible catalysts remains a significant challenge for industrial applications.In this study,graphene oxide(GO)functions as both a binder and a redox mediator,serving as a crucial"br...The mechanical performance of flexible catalysts remains a significant challenge for industrial applications.In this study,graphene oxide(GO)functions as both a binder and a redox mediator,serving as a crucial"bridge"between metal species and the organic foam,thereby substantially enhancing NO_(x) conversion efficiency.Catalytic activity tests demonstrate that the GO-modified MnCo-MS@0.05GO catalyst achieves a NO_(x) conversion rate exceeding 95%.The incorporation of GO strengthens the adhesion between the organic foam and metal components,increases the surface roughness of the sponge,and ensures the uniform and stable distribution of metal active sites.Additionally,GO enhances the content of effective catalytic species,improves electron transfer efficiency in the selective catalytic reduction reaction,and reduces diffusion resistance.To elucidate the NO reduction mechanism,in situ diffuse reflectance infrared Fourier transform spectroscopy and transient reaction studies were performed.The results indicate that as the reaction temperature increases,both the Eley-Rideal and Langmuir-Hinshelwood mechanisms contribute to promoting the SCR reaction rate.展开更多
High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional（2D） materials have attr...High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional（2D） materials have attracted attention owing to their unique physicochemical and electrochemical properties, in addition to their ability to form hetero-structures with other nanomaterials further improving mechanical and electrochemical properties. After a brief introduction of supercapacitors and 2D materials, recent progress on flexible supercapacitors using 2D materials is reviewed. Here we provide insights into the structure–property relationships of flexible electrodes, in particular free-standing films. We also present our perspectives on the development of flexible supercapacitors.展开更多
Although a new-class of heat pumps based on mechanically flexible nanoporous materials holds great poten-tial for the utilization of sustainable refrigerants with a considerably high coefficient of performance(COP),re...Although a new-class of heat pumps based on mechanically flexible nanoporous materials holds great poten-tial for the utilization of sustainable refrigerants with a considerably high coefficient of performance(COP),reducing their system volume remains a challenge.In this study,we explored the potential of this innovative type of heat pump in terms of COP and system volume.To broaden the scope of material exploration,we devised a new thermodynamic heat pump system applicable to soft mesoporous materials,in addition to the conventional system that is suitable only for flexible microporous materials.Several key factors have been identified through the comparison of various nanoporous materials and refrigerants.Our systematic investigation reveals that the combination of mechanically softer nanoporous materials with ammonia refrigerants can achieve a high COP and a reduced system volume.展开更多
Thermal runaway(TR)is considered a significant safety hazard for lithium batteries,and thermal protection materials are crucial in mitigating this risk.However,current thermal protection materials generally suffer fro...Thermal runaway(TR)is considered a significant safety hazard for lithium batteries,and thermal protection materials are crucial in mitigating this risk.However,current thermal protection materials generally suffer from poor mechanical properties,flammability,leakage,and rigid crystallization,and they struggle to continuously block excess heat transfer and propagation once thermal saturation occurs.This study proposes a novel type of thermal protection material:an aerogel coupled composite phase change material(CPCM).The composite material consists of gelatin/sodium alginate(Ge/SA)composite biomass aerogel as an insulating component and a thermally induced flexible CPCM made from thermoplastic polyester elastomer as a heat-absorbing component.Inspired by power bank,we coupled the aerogel with CPCM through the binder,so that CPCM can continue to‘charge and store energy’for the aerogel,effectively absorbing heat,delaying the heat saturation phenomenon,and maximizing the duration of thermal insulation.The results demonstrate that the Ge/SA aerogel exhibits excellent thermal insulation(with a temperature difference of approximately 120℃ across a 1 cm thickness)and flame retardancy(achieving a V-0 flame retardant rating).The CPCM exhibits high heat storage density(811.9 J g^(−1)),good thermally induced flexibility(bendable above 40℃),and thermal stability.Furthermore,the Ge/SA-CPCM coupled composite material shows even more outstanding thermal insulation performance,with the top surface temperature remaining at 89℃ after 100 min of exposure to a high temperature of 230℃.This study provides a new direction for the development of TR protection materials for lithium batteries.展开更多
With the advent of flexible/wearable electronic devices,flexible lithium-ion batteries(LIBs)have attracted significant attention as optimal power source candidates.Flexible LIBs with good flexibility,mechanical stabil...With the advent of flexible/wearable electronic devices,flexible lithium-ion batteries(LIBs)have attracted significant attention as optimal power source candidates.Flexible LIBs with good flexibility,mechanical stability,and high energy density are still an enormous challenge.In recent years,many complex and diverse design methods for flexible LIBs have been reported.The design and evaluation of ideal flexible LIBs must take into consideration both mechanical and electrochemical factors.In this review,the recent progress and challenges of flexible LIBs are reviewed from a mechano-electrochemical perspective.The recent progress in flexible LIB design is addressed concerning flexible material and configuration design.The mechanical and electrochemical evaluations of flexible LIBs are also summarized.Furthermore,mechano-electrochemical perspectives for the future direction of flexible LIBs are also discussed.Finally,the relationship between mechanical loading and the electrode process is analyzed from a mechano-electrochemical perspective.The evaluation of flexible LIBs should be based on mechano-electrochemical processes.Reviews and perspectives are of great significance to the design and practicality of flexible LIBs,which is contributed to bridging the gap between laboratory exploration and practical applications.展开更多
Since carbon nanotubes（CNTs） possess unique one dimensional（1D） structure, considerable attention has been paid to constructing CNTs into macroscopic materials with different dimensions, including 1D fibers,2D fil...Since carbon nanotubes（CNTs） possess unique one dimensional（1D） structure, considerable attention has been paid to constructing CNTs into macroscopic materials with different dimensions, including 1D fibers,2D films, and 3D foams. Such macroscopic CNT materials exhibit high conductivity, large surface area, as well as good mechanical properties, and thus can be directly used as the flexible supercapacitor（SC） electrodes or the scaffolds for supporting pseudo-capacitive electrode materials. Based on these macroscopic CNT electrodes, diverse SCs with different structures, including flexible, stretchable and/or compressible fiber and thin film SCs, have been designed. This review provides an overview of recent progress towards the development of flexible SCs based on macroscopic CNTs-based electrodes, with a focus on electrode preparation and configuration design as well as their integration with other multifunctional devices.Future development and prospects in the CNTs-based flexible SCs are also discussed.展开更多
Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform d...Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.展开更多
Free-standing electrodes are promising candidates for flexible rechargeable batteries, toward the application of flexible energy storage devices, due to their merits of additive-free, lightweight, and high energy dens...Free-standing electrodes are promising candidates for flexible rechargeable batteries, toward the application of flexible energy storage devices, due to their merits of additive-free, lightweight, and high energy density. Herein, we report a free-standing SnNb_(2)O_(6)@CSN flexible film with SnNb_(2)O_(6) encapsulated in 3D carbon skeleton nanofibers by electrospinning and carbonization processes as flexible anode for sodium-ion batteries(SIBs). The 3D carbon skeleton nanofibers serve as ion/electron transport pathway to improve the electrochemical reaction kinetics and meanwhile alleviate the volume changes of SnNb_(2)O_(6) during charge-discharge processes. The as-constructed half-cell(SnNb_(2)O_(6)@CSN‖Na) exhibits excellent cycling stability of 99.2 m Ah/g at 0.5 A/g after 950 cycles(coulombic efficiency of ~100%) and a high rate performance of 108.6 mAh/g at 10 A/g. In addition, the pouch cell can light up the LEDs at different bending angles(0°, 90°, 180°). This research shows a promising anode material for flexible energy storage electronics.展开更多
Monolayer CrN has been predicted to be half-metallic ferromagnet with high Curie temperature.Due to bulk CrN’s biocompatibility,the monolayer is a promising candidate for bio-related devices.Here,using first-principl...Monolayer CrN has been predicted to be half-metallic ferromagnet with high Curie temperature.Due to bulk CrN’s biocompatibility,the monolayer is a promising candidate for bio-related devices.Here,using first-principles calculations based on density functional theory,we find that the formation energy of the bulk CrN stacking from layers with square lattice is only 68 meV/atom above the convex hull,suggesting a great potential to fabricate the monolayer CrN in a square lattice by using molecular beam epitaxy method.The monolayer CrN is then proved to be a soft material with an ultra-low Young’s modulus and can sustain very large strains.Moreover,the analysis of the projected density of states demonstrates that the ferromagnetic half-metallicity originates from the splitting of Cr-d orbitals in the CrN square crystal field,the bonding interaction between Cr-N,and that between Cr-Cr atoms.It is worth noting that the super-exchange interaction is much larger than the direct-exchange interaction and contributes to the ultra-high Curie temperature,which is obtained from Monte Carlo simulations based on Heisenberg model.Our findings suggest that the monolayer CrN can be an indispensable candidate for nanoscale flexible spintronic applications with good biocompatibility and is considerable appealing to be realized in experiment.展开更多
Flexible wearable batteries are widely used in smartwatches, foldable phones, and fitness trackers due to their thinness and small size. Zinc-based batteries have the advantages of low cost, high safety, and ecofriend...Flexible wearable batteries are widely used in smartwatches, foldable phones, and fitness trackers due to their thinness and small size. Zinc-based batteries have the advantages of low cost, high safety, and ecofriendliness, which are considered to be the best alternative to flexible lithium-ion batteries(LIBs).Therefore, wearable flexible zinc-ion batteries(FZIBs) have attracted considerable interest as a promising energy storage device. Electrospun nanofibers(ESNFs) have great potential for application in wearable FZIBs due to their low density, high porosity, large specific surface area, and flexibility. Moreover, electrospinning technology can achieve the versatility of nanofibers through structural design and incorporation of other multifunctional materials. This paper reviews a wide range of applications of electrospinning in FZIBs, mainly in terms of cathode, anode, separator, polymer electrolyte, and all-inone flexible batteries. Firstly, the electrospinning device, principles, and influencing parameters are briefly described, showing its positive impact on FZIBs. Subsequently, the energy storage principles and electrode configurations of FZIBs are described, and some of the common problems of the batteries are illustrated, including zinc anode dendrite growth, corrosion, cathode structure collapse, and poor electrical conductivity. This is followed by a comprehensive overview of research progress on the individual components of FZIBs(cathode, anode, separator, and polymer electrolyte) from the perspective of electrostatically spun fiber materials and an in-depth study of all-in-one flexible batteries. Finally, the challenges and future development of FZIBs are individually concluded and look forward. We hope that this work will provide new ideas and avenues for the development of advanced energy technologies and smart wearable systems.展开更多
The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is estab...The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is establishedfrom the viscoelastic material constitutive,and the relationship between the kinematic response and the materialparameters is obtained.Based on the Kelvin constitutive model,a theoretical model for impact between the pro-tective body and the protected body is established,then the dynamic response is obtained.The feasibility of themodel was verified by drop hammer experiment,and the material parameters(elastic modulus,viscosity coeffi-cient)were obtained by formula.The model is discretized and the relationship between local impact response andmaterial parameters is analyzed.The discussion results on the relationship between the impact response and theprotective material performance indicate that adjusting the elastic modulus,viscosity coefficient,and thicknessof the protective material can effectively improve protective effect.展开更多
Objective Consuming phthalates may be due to the presence of food contact materials, such as plastic containers. In this study, we investigated the association between plastic container use and phthalate exposure in 2...Objective Consuming phthalates may be due to the presence of food contact materials, such as plastic containers. In this study, we investigated the association between plastic container use and phthalate exposure in 2,140 Shanghai adults. Methods Participants completed a questionnaire on the frequency of using plastic containers in different scenarios in the previous year （e.g., daily, weekly） and on the consumption of plastic-packaged foods in the previous three days （yes or no）. Urinary phthalate metabolites were used to assess the association between phthalate exposure and the use of plastic containers. Results The metabolites of di-（2-ethylhexyl） phthalate （DEHP） were the most frequently detected in urine. The results revealed that phthalate exposure was associated with consumption of plastic-packaged breakfast or processed food items in the previous three days. The consumption of these two food items had strong synergistic effects on increasing urinary concentrations of most phthalate metabolites. Conclusion Our results of plastic-packaged breakfast and processed food may be explained by the use of flexible plastic containers, indicating the importance of risk assessment for the application of flexible plastic containers.展开更多
We report a simple solution-processed method for the fabrication of low-cost,flexible optical limiting materials based on graphene oxide(GO) impregnated polyvinyl alcohol(PVA) sheets.Such GO–PVA composite sheets disp...We report a simple solution-processed method for the fabrication of low-cost,flexible optical limiting materials based on graphene oxide(GO) impregnated polyvinyl alcohol(PVA) sheets.Such GO–PVA composite sheets display highly efficient broadband optical limiting activities for femtosecond laser pulses at 400,800,and 1400 nm with very low limiting thresholds.Femtosecond pump–probe measurement results revealed that nonlinear absorption played an important role for the observed optical limiting activities.High flexibility and efficient optical limiting activities of these materials allow these composite sheets to be attached to nonplanar optical sensors in order to protect them from light-induced damage.展开更多
Background In virtual environments(VEs),users can explore a large virtual scene through the viewpoint operation of a head-mounted display(HMD)and movement gains combined with redirected walking technology.The existing...Background In virtual environments(VEs),users can explore a large virtual scene through the viewpoint operation of a head-mounted display(HMD)and movement gains combined with redirected walking technology.The existing redirection methods and viewpoint operations are effective in the horizontal direction;however,they cannot help participants experience immersion in the vertical direction.To improve the immersion of upslope walking,this study presents a virtual climbing system based on passive haptics.Methods This virtual climbing system uses the tactile feedback provided by sponges,a commonly used flexible material,to simulate the tactile sense of a user's soles.In addition,the visual stimulus of the HMD,the tactile feedback of the flexible material,and the operation of the user's walking in a VE combined with redirection technology are all adopted to enhance the user's perception in a VE.In the experiments,a physical space with a hard-flat floor and three types of sponges with thicknesses of 3,5,and 8cm were utilized.Results We recruited 40 volunteers to conduct these experiments,and the results showed that a thicker flexible material increases the difficulty for users to roam and walk within a certain range.Conclusion The virtual climbing system can enhance users'perception of upslope walking in a VE.展开更多
Vehicle skin is the key component in maintaining the aerodynamic shape of the vehicle.A deformable high-speed vehicle needs to adjust its shape in real time to realize optimum aerodynamic efficiency and to withstand e...Vehicle skin is the key component in maintaining the aerodynamic shape of the vehicle.A deformable high-speed vehicle needs to adjust its shape in real time to realize optimum aerodynamic efficiency and to withstand extreme heat flow induced by high-speed flight,which requires the skin to possess large strain and high-temperature resistance.Traditional vehicle skin cannot satisfy both of the requirements.Biomimetic flexible skin for deformable high-speed vehicles(DHSV-bio-FS)combines flexible material fabrication with transpiration cooling technology,which can simulate human skin sweat cooling,and has the characteristics of large strain and high-temperature resistance.The thermal protection performance of the prepared prototype of DHSV-bio-FS was evaluated by simulation and wind tunnel experiments at 40% tensile strain with liquid water as coolant.Simulation results suggest that the surface temperature of the DHSV-bio-FS at 40% tensile strain is consistent with the temperature of the coolant(350 K)in a 3,000 K high-temperature gas environment.In addition,the prepared prototype DHSV-bio-FS survived for 1,200 s in a high-temperature gas environment of 200 kW/m^(2)in wind tunnel experiments.This paper verifies the reliability of DHSV-bio-FS in a high-temperature gas environment and can be deployed in applications of flexible skin for deformable high-speed vehicles(DHSV-FS).展开更多
Piezoelectric materials are capable of converting between mechanical and electrical energy,and are suitable for sensing,actuating and energy harvesting.While most conventional piezoelectric materials are brittle solid...Piezoelectric materials are capable of converting between mechanical and electrical energy,and are suitable for sensing,actuating and energy harvesting.While most conventional piezoelectric materials are brittle solids,flexible piezoelectric materials(FPM)retain functionality even under bending and stretching conditions.This characteristic has garnered increasing attention in recent years,particularly for wearable devices,where the ability to adapt to dynamic human movements is essential.In addition,wearable devices also demand excellent conformability,durability,and adaptability to miniaturization.FPM emerge as a promising solution that meet all these requirements.This review thus aims to offer a comprehensive summary of recent advances in the field of FPM,including piezoelectric polymers,composites,and inorganic flexible films.We introduce and categorize the specific features of these materials and highlight their emerging applications in electronic devices,and comment on the prospect of FPM as well as their potential challenges.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.32201499,32222057,and 22478142)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515012519,2023A0505050114,and 2024B1515040004)+1 种基金National Key Research and Development Project(Grant No 2023YFE0109600)State Key Laboratory of Advanced Papermaking and Paper-based Materials(2024C02).
文摘The rapid development of portable electronics,wearable technologies,and healthcare monitoring systems necessitates the innovation of flexible energy storage systems.Considering environmental pollution and the depletion of fossil resources,the utilization of renewable resources to engineer advanced flexible materials has become especially crucial.Cellulose,the most abundant natural polymer,has emerged as a promising precursor for advanced functional materials due to its unique structure and properties.Typically,the easy processability,tunable chemical structure,self-assembly behavior,mechanical strength,and reinforcing capability enable its utilization as binder,substrate,hybrid electrode,separator,and electrolyte reservoir for flexible energy storage devices.This review comprehensively summarizes the design,fabrication,and mechanical and electrochemical performances of cellulose-based materials.The structure and unique properties of cellulose are first briefly introduced.Then,the construction of cellulose-based materials in the forms of 1D fibers/filaments,2D films/membranes,3D hydrogels and aerogels is discussed,and the merits of cellulose in these materials are emphasized.After that,the various advanced applications in supercapacitors,lithium-ion batteries,lithium-sulfur batteries,sodium-ion batteries,metal-air batteries,and Zn-ion batteries are presented in detail.Finally,an outlook of the potential challenges and future perspectives in advanced cellulose-based materials for flexible energy storage systems is discussed.
基金This work was financially supported by the National Natural Science Foundation of China(51725101,11727807,51672050,61790581,52102368,52101213)the Ministry of Science and Technology of China(973 Project No.2018YFA0209102)+6 种基金University Development Fund(UDF0100152)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(Grant No.2017ZT07C291)Shenzhen Science and Technology Program(Grant No.KQTD20170810141424366)China Postdoctoral Science Foundation(Grant No.2020M680085)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905)Science and Technology Department of Jiangsu Province of China(Grant No.BK20210261)Open access funding provided by Shanghai Jiao Tong University
文摘With rapid development of 5G communication technologies,electromagnetic interference(EMI)shielding for electronic devices has become an urgent demand in recent years,where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role.Meanwhile,the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications.Hitherto,a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed.In this review,we not only introduce the recent development of flexible EMI shielding materials,but also elaborate the EMI shielding mechanisms and the index for"green EMI shielding"performance.In addition,the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized.Finally,we propose several possible research directions for flexible EMI shielding materials in near future,which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.
基金supported by the National Natural Science Foundation of China(Grants No.51109143 and 51209144)the Natural Science Foundation of Jiangsu Province(Grant No.BK2011109)the Foundation of Nanjing Hydraulic Research Institute(Grant No.Y113004)
文摘In this study, several kinds of flexible protective materials sprayed with polyurea elastomers （hereinafter referred to as polyurea elastomer protective material） were adopted to meet the abrasion resistance requirement of hydraulic structures, and their abrasion resistances against the water flow with suspended load or bed load were studied systematically through tests. Natural basalt stones were adopted as the abrasive for simulation of the abrasion effect of the water flow with bed load, and test results indicate that the basalt stone is suitable for use in the abrasion resistance test of the flexible protective material. The wear process of the polyurea elastomer protective material is stable, and the wear loss is linear with the time of abrasion. If the wear thickness is regarded as the abrasion resistance evaluation factor, the abrasion resistance of the 351 pure polyurea is about twice those of pure polyurea with a high level of hardness and aliphatic polyurea, and over five times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with suspended load. It is also about 50 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load. Overall, the abrasion resistance of pure polyurea presented a decreasing trend with increasing hardness. Pure polyurea with a Shore hardness of D30 has the best abrasion resistance, which is 60 to 70 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load, and has been recommended, among the five kinds of pure polyurea materials with different hardness, in anti-abrasion protection of hydraulic structures.
文摘The mechanical performance of flexible catalysts remains a significant challenge for industrial applications.In this study,graphene oxide(GO)functions as both a binder and a redox mediator,serving as a crucial"bridge"between metal species and the organic foam,thereby substantially enhancing NO_(x) conversion efficiency.Catalytic activity tests demonstrate that the GO-modified MnCo-MS@0.05GO catalyst achieves a NO_(x) conversion rate exceeding 95%.The incorporation of GO strengthens the adhesion between the organic foam and metal components,increases the surface roughness of the sponge,and ensures the uniform and stable distribution of metal active sites.Additionally,GO enhances the content of effective catalytic species,improves electron transfer efficiency in the selective catalytic reduction reaction,and reduces diffusion resistance.To elucidate the NO reduction mechanism,in situ diffuse reflectance infrared Fourier transform spectroscopy and transient reaction studies were performed.The results indicate that as the reaction temperature increases,both the Eley-Rideal and Langmuir-Hinshelwood mechanisms contribute to promoting the SCR reaction rate.
基金Funding from the Australian Research Council Centre of Excellence Scheme(CE 140100012)the funding from National Natural Science Foundation of China(51502206)+1 种基金the CSC scholarship from the Ministry of Education of PR Chinathe support of the CSC scholarship from the Ministry of Education of PR China
文摘High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional（2D） materials have attracted attention owing to their unique physicochemical and electrochemical properties, in addition to their ability to form hetero-structures with other nanomaterials further improving mechanical and electrochemical properties. After a brief introduction of supercapacitors and 2D materials, recent progress on flexible supercapacitors using 2D materials is reviewed. Here we provide insights into the structure–property relationships of flexible electrodes, in particular free-standing films. We also present our perspectives on the development of flexible supercapacitors.
文摘Although a new-class of heat pumps based on mechanically flexible nanoporous materials holds great poten-tial for the utilization of sustainable refrigerants with a considerably high coefficient of performance(COP),reducing their system volume remains a challenge.In this study,we explored the potential of this innovative type of heat pump in terms of COP and system volume.To broaden the scope of material exploration,we devised a new thermodynamic heat pump system applicable to soft mesoporous materials,in addition to the conventional system that is suitable only for flexible microporous materials.Several key factors have been identified through the comparison of various nanoporous materials and refrigerants.Our systematic investigation reveals that the combination of mechanically softer nanoporous materials with ammonia refrigerants can achieve a high COP and a reduced system volume.
基金supported by the National Key Research and Development Program of China(2022YFB3806501)the National Natural Science Foundation of China(22178050,22108026)+3 种基金the Young Elite Scientists Sponsorship Program by CAST(2021QNRC001)the Natural Science Foundation of Liaoning Province(2022-BS-091)the Dalian Science and Technology Innovation Fund Young Tech Star(2022RQ008)the Fundamental Research Funds for the Central Universities(DUT22LAB610).
文摘Thermal runaway(TR)is considered a significant safety hazard for lithium batteries,and thermal protection materials are crucial in mitigating this risk.However,current thermal protection materials generally suffer from poor mechanical properties,flammability,leakage,and rigid crystallization,and they struggle to continuously block excess heat transfer and propagation once thermal saturation occurs.This study proposes a novel type of thermal protection material:an aerogel coupled composite phase change material(CPCM).The composite material consists of gelatin/sodium alginate(Ge/SA)composite biomass aerogel as an insulating component and a thermally induced flexible CPCM made from thermoplastic polyester elastomer as a heat-absorbing component.Inspired by power bank,we coupled the aerogel with CPCM through the binder,so that CPCM can continue to‘charge and store energy’for the aerogel,effectively absorbing heat,delaying the heat saturation phenomenon,and maximizing the duration of thermal insulation.The results demonstrate that the Ge/SA aerogel exhibits excellent thermal insulation(with a temperature difference of approximately 120℃ across a 1 cm thickness)and flame retardancy(achieving a V-0 flame retardant rating).The CPCM exhibits high heat storage density(811.9 J g^(−1)),good thermally induced flexibility(bendable above 40℃),and thermal stability.Furthermore,the Ge/SA-CPCM coupled composite material shows even more outstanding thermal insulation performance,with the top surface temperature remaining at 89℃ after 100 min of exposure to a high temperature of 230℃.This study provides a new direction for the development of TR protection materials for lithium batteries.
基金supported by National Natural Science Foundation of China(No.52074036)Technology Innovation Program of Beijing Institute of Technology(No.2019CX01021)BIT Teli Young Fellow。
文摘With the advent of flexible/wearable electronic devices,flexible lithium-ion batteries(LIBs)have attracted significant attention as optimal power source candidates.Flexible LIBs with good flexibility,mechanical stability,and high energy density are still an enormous challenge.In recent years,many complex and diverse design methods for flexible LIBs have been reported.The design and evaluation of ideal flexible LIBs must take into consideration both mechanical and electrochemical factors.In this review,the recent progress and challenges of flexible LIBs are reviewed from a mechano-electrochemical perspective.The recent progress in flexible LIB design is addressed concerning flexible material and configuration design.The mechanical and electrochemical evaluations of flexible LIBs are also summarized.Furthermore,mechano-electrochemical perspectives for the future direction of flexible LIBs are also discussed.Finally,the relationship between mechanical loading and the electrode process is analyzed from a mechano-electrochemical perspective.The evaluation of flexible LIBs should be based on mechano-electrochemical processes.Reviews and perspectives are of great significance to the design and practicality of flexible LIBs,which is contributed to bridging the gap between laboratory exploration and practical applications.
基金supported by the MOST (Ministry of Science and Technology of China) (No. 2017YFA0206701)NSFC (National Natural Science Foundation of China) (Nos. 51602218, 21573116, 11604242)+1 种基金MOE (Ministry of Education of China) (No. B12015)Tianjin Basic and High-Tech Development (No. 15JCYBJC17300)
文摘Since carbon nanotubes（CNTs） possess unique one dimensional（1D） structure, considerable attention has been paid to constructing CNTs into macroscopic materials with different dimensions, including 1D fibers,2D films, and 3D foams. Such macroscopic CNT materials exhibit high conductivity, large surface area, as well as good mechanical properties, and thus can be directly used as the flexible supercapacitor（SC） electrodes or the scaffolds for supporting pseudo-capacitive electrode materials. Based on these macroscopic CNT electrodes, diverse SCs with different structures, including flexible, stretchable and/or compressible fiber and thin film SCs, have been designed. This review provides an overview of recent progress towards the development of flexible SCs based on macroscopic CNTs-based electrodes, with a focus on electrode preparation and configuration design as well as their integration with other multifunctional devices.Future development and prospects in the CNTs-based flexible SCs are also discussed.
基金Supported by National Natural Science Foundation of China(Grant Nos.51205004,51475003)Beijing Municipal Natural Science Foundation of China(Grant No.3152010)Beijing Municipal Education Committee Science and Technology Program,China(Grant No.KM201510009004)
文摘Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.
基金financially supported by the National Natural Science Foundation of China (Nos. 51774251, 22179077)the Natural Science Foundation in Shanghai (No. 21ZR1424200)+2 种基金the Shanghai Science and Technology Commission's "2020 Science and Technology In-novation Action Plan" (No. 20511104003)the Hebei Natural Science Foundation for Distinguished Young Scholars (No. B2017203313)the Scientific Research Foundation for the Returned Overseas Chinese Scholars (No. CG2014003002)。
文摘Free-standing electrodes are promising candidates for flexible rechargeable batteries, toward the application of flexible energy storage devices, due to their merits of additive-free, lightweight, and high energy density. Herein, we report a free-standing SnNb_(2)O_(6)@CSN flexible film with SnNb_(2)O_(6) encapsulated in 3D carbon skeleton nanofibers by electrospinning and carbonization processes as flexible anode for sodium-ion batteries(SIBs). The 3D carbon skeleton nanofibers serve as ion/electron transport pathway to improve the electrochemical reaction kinetics and meanwhile alleviate the volume changes of SnNb_(2)O_(6) during charge-discharge processes. The as-constructed half-cell(SnNb_(2)O_(6)@CSN‖Na) exhibits excellent cycling stability of 99.2 m Ah/g at 0.5 A/g after 950 cycles(coulombic efficiency of ~100%) and a high rate performance of 108.6 mAh/g at 10 A/g. In addition, the pouch cell can light up the LEDs at different bending angles(0°, 90°, 180°). This research shows a promising anode material for flexible energy storage electronics.
基金Project supported by the National Natural Science Foundation of China(Grant No.61888102)the National Key Research and Development Program of China(Grant No.2016YFA0202300)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB30000000)。
文摘Monolayer CrN has been predicted to be half-metallic ferromagnet with high Curie temperature.Due to bulk CrN’s biocompatibility,the monolayer is a promising candidate for bio-related devices.Here,using first-principles calculations based on density functional theory,we find that the formation energy of the bulk CrN stacking from layers with square lattice is only 68 meV/atom above the convex hull,suggesting a great potential to fabricate the monolayer CrN in a square lattice by using molecular beam epitaxy method.The monolayer CrN is then proved to be a soft material with an ultra-low Young’s modulus and can sustain very large strains.Moreover,the analysis of the projected density of states demonstrates that the ferromagnetic half-metallicity originates from the splitting of Cr-d orbitals in the CrN square crystal field,the bonding interaction between Cr-N,and that between Cr-Cr atoms.It is worth noting that the super-exchange interaction is much larger than the direct-exchange interaction and contributes to the ultra-high Curie temperature,which is obtained from Monte Carlo simulations based on Heisenberg model.Our findings suggest that the monolayer CrN can be an indispensable candidate for nanoscale flexible spintronic applications with good biocompatibility and is considerable appealing to be realized in experiment.
基金National Natural Science Foundation of China (52103061)Young Elite Scientist Sponsorship Program by China Association for Science and Technology (YESS20220298)+2 种基金Tianjin Enterprise Science and Technology Commissioner Project (23YDTPJC00400)China Postdoctoral Science Foundation (2021T140419, 2022M711959)State Key Laboratory of Membrane and Membrane Separation, Tiangong University。
文摘Flexible wearable batteries are widely used in smartwatches, foldable phones, and fitness trackers due to their thinness and small size. Zinc-based batteries have the advantages of low cost, high safety, and ecofriendliness, which are considered to be the best alternative to flexible lithium-ion batteries(LIBs).Therefore, wearable flexible zinc-ion batteries(FZIBs) have attracted considerable interest as a promising energy storage device. Electrospun nanofibers(ESNFs) have great potential for application in wearable FZIBs due to their low density, high porosity, large specific surface area, and flexibility. Moreover, electrospinning technology can achieve the versatility of nanofibers through structural design and incorporation of other multifunctional materials. This paper reviews a wide range of applications of electrospinning in FZIBs, mainly in terms of cathode, anode, separator, polymer electrolyte, and all-inone flexible batteries. Firstly, the electrospinning device, principles, and influencing parameters are briefly described, showing its positive impact on FZIBs. Subsequently, the energy storage principles and electrode configurations of FZIBs are described, and some of the common problems of the batteries are illustrated, including zinc anode dendrite growth, corrosion, cathode structure collapse, and poor electrical conductivity. This is followed by a comprehensive overview of research progress on the individual components of FZIBs(cathode, anode, separator, and polymer electrolyte) from the perspective of electrostatically spun fiber materials and an in-depth study of all-in-one flexible batteries. Finally, the challenges and future development of FZIBs are individually concluded and look forward. We hope that this work will provide new ideas and avenues for the development of advanced energy technologies and smart wearable systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.12172151 and 12172149).
文摘The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is establishedfrom the viscoelastic material constitutive,and the relationship between the kinematic response and the materialparameters is obtained.Based on the Kelvin constitutive model,a theoretical model for impact between the pro-tective body and the protected body is established,then the dynamic response is obtained.The feasibility of themodel was verified by drop hammer experiment,and the material parameters(elastic modulus,viscosity coeffi-cient)were obtained by formula.The model is discretized and the relationship between local impact response andmaterial parameters is analyzed.The discussion results on the relationship between the impact response and theprotective material performance indicate that adjusting the elastic modulus,viscosity coefficient,and thicknessof the protective material can effectively improve protective effect.
基金supported by the National Key Research and Development Program of China(No.2016YFD0400602)
文摘Objective Consuming phthalates may be due to the presence of food contact materials, such as plastic containers. In this study, we investigated the association between plastic container use and phthalate exposure in 2,140 Shanghai adults. Methods Participants completed a questionnaire on the frequency of using plastic containers in different scenarios in the previous year （e.g., daily, weekly） and on the consumption of plastic-packaged foods in the previous three days （yes or no）. Urinary phthalate metabolites were used to assess the association between phthalate exposure and the use of plastic containers. Results The metabolites of di-（2-ethylhexyl） phthalate （DEHP） were the most frequently detected in urine. The results revealed that phthalate exposure was associated with consumption of plastic-packaged breakfast or processed food items in the previous three days. The consumption of these two food items had strong synergistic effects on increasing urinary concentrations of most phthalate metabolites. Conclusion Our results of plastic-packaged breakfast and processed food may be explained by the use of flexible plastic containers, indicating the importance of risk assessment for the application of flexible plastic containers.
基金financial support from the Guangdong Innovative Research Team Program of China (201101C0105067115)DSTA Singapore (Project DSTA-NUS-DIRP/9010100347)National Research Foundation Singapore (R398-001-062-281)
文摘We report a simple solution-processed method for the fabrication of low-cost,flexible optical limiting materials based on graphene oxide(GO) impregnated polyvinyl alcohol(PVA) sheets.Such GO–PVA composite sheets display highly efficient broadband optical limiting activities for femtosecond laser pulses at 400,800,and 1400 nm with very low limiting thresholds.Femtosecond pump–probe measurement results revealed that nonlinear absorption played an important role for the observed optical limiting activities.High flexibility and efficient optical limiting activities of these materials allow these composite sheets to be attached to nonplanar optical sensors in order to protect them from light-induced damage.
基金supported by the National Natural Science Foundation of China(Grant Nos.51975392 and 51775360)the National Key Research and Development Program(Grant No.2021YFB3400300)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.19KJA220001)the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20201412 and BK20221361).
基金the National Key R&D Program of China(2018YFB1404100)National Natural Science Foundation of China(62072405)Zhejiang Provincial Natural Science Foundation of China(LGF20F020017).
文摘Background In virtual environments(VEs),users can explore a large virtual scene through the viewpoint operation of a head-mounted display(HMD)and movement gains combined with redirected walking technology.The existing redirection methods and viewpoint operations are effective in the horizontal direction;however,they cannot help participants experience immersion in the vertical direction.To improve the immersion of upslope walking,this study presents a virtual climbing system based on passive haptics.Methods This virtual climbing system uses the tactile feedback provided by sponges,a commonly used flexible material,to simulate the tactile sense of a user's soles.In addition,the visual stimulus of the HMD,the tactile feedback of the flexible material,and the operation of the user's walking in a VE combined with redirection technology are all adopted to enhance the user's perception in a VE.In the experiments,a physical space with a hard-flat floor and three types of sponges with thicknesses of 3,5,and 8cm were utilized.Results We recruited 40 volunteers to conduct these experiments,and the results showed that a thicker flexible material increases the difficulty for users to roam and walk within a certain range.Conclusion The virtual climbing system can enhance users'perception of upslope walking in a VE.
基金supported by the Major Research Plan of the National Natural Science Foundation of China(Grant No.92271201)the Natural Science Basic Research Program of Shaanxi(Program No.2024JC-JCQN-61).
文摘Vehicle skin is the key component in maintaining the aerodynamic shape of the vehicle.A deformable high-speed vehicle needs to adjust its shape in real time to realize optimum aerodynamic efficiency and to withstand extreme heat flow induced by high-speed flight,which requires the skin to possess large strain and high-temperature resistance.Traditional vehicle skin cannot satisfy both of the requirements.Biomimetic flexible skin for deformable high-speed vehicles(DHSV-bio-FS)combines flexible material fabrication with transpiration cooling technology,which can simulate human skin sweat cooling,and has the characteristics of large strain and high-temperature resistance.The thermal protection performance of the prepared prototype of DHSV-bio-FS was evaluated by simulation and wind tunnel experiments at 40% tensile strain with liquid water as coolant.Simulation results suggest that the surface temperature of the DHSV-bio-FS at 40% tensile strain is consistent with the temperature of the coolant(350 K)in a 3,000 K high-temperature gas environment.In addition,the prepared prototype DHSV-bio-FS survived for 1,200 s in a high-temperature gas environment of 200 kW/m^(2)in wind tunnel experiments.This paper verifies the reliability of DHSV-bio-FS in a high-temperature gas environment and can be deployed in applications of flexible skin for deformable high-speed vehicles(DHSV-FS).
基金supported by National Natural Science Foundation of China(No.12474213,52032005,82225012,52325204,and U22A20254)National Key Research and Development Program of China(No.2024YFF1400700)supported by Wuzhen Laboratory,and Deutsche Forschungsgemeinschaft(No.414311761).
文摘Piezoelectric materials are capable of converting between mechanical and electrical energy,and are suitable for sensing,actuating and energy harvesting.While most conventional piezoelectric materials are brittle solids,flexible piezoelectric materials(FPM)retain functionality even under bending and stretching conditions.This characteristic has garnered increasing attention in recent years,particularly for wearable devices,where the ability to adapt to dynamic human movements is essential.In addition,wearable devices also demand excellent conformability,durability,and adaptability to miniaturization.FPM emerge as a promising solution that meet all these requirements.This review thus aims to offer a comprehensive summary of recent advances in the field of FPM,including piezoelectric polymers,composites,and inorganic flexible films.We introduce and categorize the specific features of these materials and highlight their emerging applications in electronic devices,and comment on the prospect of FPM as well as their potential challenges.
