SnO_(2) has been extensively investigated as an anode material for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs)due to its high Na/K storage capacity,high abundance,and low toxicity.However,the sluggish ...SnO_(2) has been extensively investigated as an anode material for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs)due to its high Na/K storage capacity,high abundance,and low toxicity.However,the sluggish reaction kinetics,low electronic conductivity,and large volume changes during charge and discharge hinder the practical applications of SnO_(2)-based electrodes for SIBs and PIBs.Engineering rational structures with fast charge/ion transfer and robust stability is important to overcoming these challenges.Herein,S-doped SnO_(2)(S-SnO_(2))quantum dots(QDs)(≈3 nm)encapsulated in an N,S codoped carbon fiber networks(S-SnO_(2)-CFN)are rationally fabricated using a sequential freeze-drying,calcination,and S-doping strategy.Experimental analysis and density functional theory calculations reveal that the integration of S-SnO_(2) QDs with N,S codoped carbon fiber network remarkably decreases the adsorption energies of Na/K atoms in the interlayer of SnO_(2)-CFN,and the S doping can increase the conductivity of SnO_(2),thereby enhancing the ion transfer kinetics.The synergistic interaction between S-SnO_(2) QDs and N,S codoped carbon fiber network results in a composite with fast Na+/K+storage and extraordinary long-term cyclability.Specifically,the S-SnO_(2)-CFN delivers high rate capacities of 141.0 mAh g^(−1) at 20 A g^(−1) in SIBs and 102.8 mAh g^(−1) at 10 A g^(−1) in PIBs.Impressively,it delivers ultra-stable sodium storage up to 10,000 cycles at 5 A g^(−1) and potassium storage up to 5000 cycles at 2 A g^(−1).This study provides insights into constructing metal oxide-based carbon fiber network structures for high-performance electrochemical energy storage and conversion devices.展开更多
A new production line has officially started operating at a green energy industrial park in the Shanxi Yungang Economic Development Zone.Tens of thousands of hair-thin black filaments flow uniformly like gleaming dark...A new production line has officially started operating at a green energy industrial park in the Shanxi Yungang Economic Development Zone.Tens of thousands of hair-thin black filaments flow uniformly like gleaming dark rivers from the winding machines.The Institute of Coal Chemistry of the Chinese Academy of Sciences(CAS)developed T1000-grade high-performance carbon fiber here,and it has fully independent intellectual property rights.“It took us 20 years to go from having‘no grain to cook’to achieving‘high-end iteration,’”said Zhang Shouchun,Deputy Director of the Institute of Coal Chemistry,CAS,and project leader.Behind this striking black thread lies an arduous,persistent campaign of material innovation.展开更多
Carbon fibers(CFs)are widely used in cutting-edge and civilian fields due to their excellent comprehensive properties such as high strength and high modulus,superior corrosion and friction resistances,excellent therma...Carbon fibers(CFs)are widely used in cutting-edge and civilian fields due to their excellent comprehensive properties such as high strength and high modulus,superior corrosion and friction resistances,excellent thermal stability,light weight,and high electrical conductivity.However,their natural ultra-black appearance is difficult to meet the aesthetic needs of today's civilian sector and the need for optical stealth in the military field.In addition,conventional coloring methods are difficult to effectively adhere to CF surfaces due to high crystallinity and highly inert surface caused by their graphite-like structure.In this work,inspired by the nacre structural color of pearls,colored CFs with 1D photonic crystal structure are prepared by cyclically depositing amorphous(Al_(2)O_(3)+TiO_(2))layers on the surface of carbon CFs through atomic layer deposition(ALD).The obtained CFs exhibit brilliant colors and excellent environmental durability in extreme environments.Moreover,the colored CFs also exhibit high EMI shielding effectiveness(45 dB)and optical stealth properties,which can be used in emerging optical devices and electromagnetic and optical stealth equipment.展开更多
Carbon fiber-reinforced plastics (CFRPs) possess pronounced anisotropic properties, necessitating advancements in through-thickness electrical conductivity and other functionalities without compromising mechanical int...Carbon fiber-reinforced plastics (CFRPs) possess pronounced anisotropic properties, necessitating advancements in through-thickness electrical conductivity and other functionalities without compromising mechanical integrity. MXenes, as an emerging family of two-dimensional nanomaterials, have demonstrated significant potential for enhancement modification in this area. However, achieving uniform distribution and effective utilization on a large scale with low filler content has posed a significant challenge. Herein, a highly lightweight, flexible, and functional Ti_(3)C_(2)T_(x)/ poly(3,4-ethylene-dioxythiophene) poly (styrene sulfonate) (PEDOT: PSS) /Ammonium polyphosphate (APP) reclaimed carbon fiber (rCF) veil reinforced plastics (MPA-rCFRPs) was fabricated through large-scale vacuum-assisted filtration and autoclave technology. The modified MPA-rCFRPs have exhibited substantial improvements in electromagnetic shielding with MXene additive amounts as low as 0.24 %-1.07 %, increasing the electro-magnetic interference shielding effectiveness (EMI SE) to 87.12 dB, improved by 350.02 %. Remarkably, the through-thickness electrical conductivity of MPA-rCFRPs exhibited a 767.14 % improvement, escalating from 19.73 S/m to 151.41 S/m. Meanwhile, the modified composites have exhibited enhanced photothermal, electrothermal, and flame-retardant properties, and the above improvements have not shown a significant impact on the mechanical properties of the material. This work represents a practical solution for the construction of large-scale MXene-based carbon fiber composites and opens the door to functional reutilization of rCF materials.展开更多
With the rapid development of electronic information technology,the waste electromagnetic radiation generated by the wireless and various other electronic devices has caused serious harm to human health.The developmen...With the rapid development of electronic information technology,the waste electromagnetic radiation generated by the wireless and various other electronic devices has caused serious harm to human health.The development of high-efficiency flexible electromagnetic interference(EMI)shielding materials has become one of the most effective ways to mitigate the increasingly serious problem of electromagnetic pollution.Flexible carbon fiber composites possess most of the physical requirements needed for EMI shielding applications,including high electrical conductivity,large specific surface area,light weight,flexibility,porous structure,and adjustable physical and chemical properties,and various morphology of carbon fibers-based composites applied EMI.In this review,the primary EMI shielding mechanism of carbonfiber-based materials is presented.Since carbon fiber suffers from a low absorption efficiency when used for EMI shielding by itself,it is usually combined with additional EMI filling materials.Therefore,the methods of adding EMI filler materials to the carbon fiber framework and the influence of different fillers on the EMI shielding performance are also discussed.In addition,the novel structural designs of flexible carbon fiber-based EMI shielding materials,including fiber orientation,core-shell structure,and multilayer heterostructure,are summarized in terms of their classification,which includes composites with metal,polymer,nano-carbon,and MXenes.The review concludes with a brief discussion of the challenges,research directions,and future prospects of carbon-fiber-based EMI shielding materials.展开更多
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
Micro-coiled chiral carbon fibers are modified by nano-Ni. X-ray diffraction （XRD） and scanning electron microscopy （SEM） are used to compare the composition and morphology of the unmodified and the modified fiber...Micro-coiled chiral carbon fibers are modified by nano-Ni. X-ray diffraction （XRD） and scanning electron microscopy （SEM） are used to compare the composition and morphology of the unmodified and the modified fibers. The results show that electromagnetism parameters of the modified are different from those of the unmodified. After modification by nano-Ni, the micro-coiled chiral carbon fibers have decreased permittivity and electrical loss. The permeability and magnetic loss of the modified carbon fibers become larger than those of the unmodified ones. Moreover, the modification of unmodified chiral carbon fibers into the modified is much like changing hollow electric windings into those with magnetic cores inside. The modifier intensifies the cross polarization of the chiral carbon fibers and makes the permittivity and the permeability get closer to each other which improves the matching performance and enhances absorbability of coatings. In the range of 6-18 GHz, the reflectivity of the coating is 6-8dB and the bandwidth is 12 GHz. The area density of the coating is below 3 kg/m^2.展开更多
Carbon fibers(CFs)with notable comprehensive properties,such as light weight,high specific strength,and stiffness,have garnered considerable interest in both academic and industrial fields due to their diverse and adv...Carbon fibers(CFs)with notable comprehensive properties,such as light weight,high specific strength,and stiffness,have garnered considerable interest in both academic and industrial fields due to their diverse and advanced applications.However,the commonly utilized precursors,such as polyacrylonitrile and pitch,exhibit a lack of environmental sustainability,and their costs are heavily reliant on fluctuating petroleum prices.To meet the substantial market demand for CFs,significant efforts have been made to develop cost-effective and sustainable CFs derived from biomass.Lignin,the most abundant polyphenolic compound in nature,is emerging as a promising precursor which is well-suited for the production of CFs due to its renewable nature,low cost,high carbon content,and aromatic structures.Nevertheless,the majority of lignin raw materials are currently derived from pulping and biorefining industrial by-products,which are diverse and heterogeneous in nature,restricting the industrialization of lignin-derived CFs.This review classifies fossil-derived and biomass-derived CFs,starting from the sources and chemical structures of raw lignin,and outlines the preparation methods linked to the performance of lignin-derived CFs.A comprehensive discussion is presented on the relationship between the structural characteristics of lignin,spinning preparation,and structure-morphology-property of ligninderived CFs.Additionally,the potential applications of these materials in various domains,including energy,catalysis,composites,and other advanced products,are also described with the objective of spotlighting the unique merits of lignin.Finally,the current challenges faced and future prospects for the advancement of lignin-derived CFs are proposed.展开更多
The ACF adsorbent with high Cu loading was treated with dielectric barrier discharge plasma to mitigate the negative effects of high Cu loading and enhance PH_(3)and H_(2)S adsorption and oxidation.Bruno-Emmett-Taylor...The ACF adsorbent with high Cu loading was treated with dielectric barrier discharge plasma to mitigate the negative effects of high Cu loading and enhance PH_(3)and H_(2)S adsorption and oxidation.Bruno-Emmett-Taylor(BET)result showed that the specific surface area of the adsorbent after air plasma modification was almost three times that before modification.X-ray photoelectron spectroscopy(XPS)findings revealed that the amino group was added to the adsorbent's surface,increasing lattice oxygen and chemisorbed oxygen.The adsorbent's large specific surface area,excellent surface active oxygen,and abundance of basic groups facilitate PH_(3)and H_(2)S adsorption and oxidation.The scanning electron microscopy showed that air plasma modification exposed more active components and uniformly dispersed them on the surface of adsorbent,thereby improving the adsorption performance.Activity evaluation results showed that the adsorbent has the best ability to capture PH_(3)and H_(2)S after being modified by air plasma at 4 kV voltage for 10 min.The adsorbent's breakthrough ability at high space velocity(WHSV:60,000 h^(−1))is 190 mg P/g and 146 mg S/g,respectively,which is 74%and 60%greater than that before modification.This is a great improvement over previous studies.In addition,the possible mechanism of adsorbent deactivation was proposed.展开更多
To reduce electromagnetic(EM)wave interference pollution,in this work,carbon fibers@Co-ZIFs derivations(CFZD)as an advanced EM wave absorbing material was successfully prepared.The yolk-shell structure of the magnetic...To reduce electromagnetic(EM)wave interference pollution,in this work,carbon fibers@Co-ZIFs derivations(CFZD)as an advanced EM wave absorbing material was successfully prepared.The yolk-shell structure of the magnetic metal particles generated a large amount of contact area,facilitating the interface polarization and relaxation.As a result,the optimized sample delivers a maximum reflection loss(RL)value of-19.2 d B with a bandwidth of 2.6 GHz at a small thickness of 1.3 mm.Additionally,ANSYS Electronics Desktop 2018(HFSS)was used to simulate the radar cross section(RCS)reduction in practical application based on these composites.The RCS values of composite coatings are less than-10 d B m^(2) at the range of-90°<theta<-10°and 10°<theta<90°,which indicate the effective reduction of the radar reflection signal by the composite coatings.The work is of reference significance for preparing great absorbing materials and designing absorbing coatings by combining simulation method.展开更多
Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are kn...Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are known for their unique compact structure;they are not only lightweight but also strong.In this study,an in-depth look at owl feathers was made and it found that owl feathers not only have the macro branches structure between feather shafts and branches but also have fine feather structures on the branches.The presence of these fine feather structures increases the specific surface area of the plume branches and allows neighboring plume branches to hook up with each other,forming an effective mechanical interlocking structure.These structures bring owl feathers excellent mechanical properties.Inspired by the natural structure of owl feathers,a weaving technique and a sizing process were combined to prepare bionic Carbon Fiber(CF)fabrics and then to fabricate the bionic CFRP with structural characteristics similar to owl feathers.To evaluate the effect of the fine feather structure on the mechanical properties of CFRP,a mechanical property study on CFRP with and without the fine feather imitation structure were conducted.The experimental results show that the introduction of the fine feather branch structure enhance the mechanical properties of CFRP significantly.Specifically,the tensile strength of the composites increased by 6.42%and 13.06%and the flexural strength increased by 8.02%and 16.87%in the 0°and 90°sample directions,respectively.These results provide a new design idea for the improvement of the mechanical properties of the CFRP,promoting the application of CFRP in engineering fields,such as automotive transportation,rail transit,aerospace,and construction.展开更多
Combined nitric acid oxidation method and polyaniline （PANI）-coated method were applied to modify the surface properties of short carbon fibers （SCF）. The electrical and mechanical properties of acrylic coatings w...Combined nitric acid oxidation method and polyaniline （PANI）-coated method were applied to modify the surface properties of short carbon fibers （SCF）. The electrical and mechanical properties of acrylic coatings with 50 wt pct PANI-coated carbon fiber were investigated by using scanning electron microscope （SEM）, UV-Vis spectrophotometer, four-probe method and the coaxial cable method. The results of the pH measurement and XPS （X-ray photoelectron spectroscopy） patterns showed that the oxygen functional groups, such as -OH and -COOH, were attached on the carbon fiber surfaces after oxidation treatment. The XPS analysis of PANl-coated oxidized SCF （PAOSCF） revealed that PANI may bond on the surface of oxidized SCF with chemical bonds. SEM images and surface roughness analyses showed that PANl-coated layer changed the surface morphology. Compared with SCF/acrylic coating, the surface resistivity of PAOSCF/acrylic coating decreased from17.1 to 5.3 Ω/sq and the shielding efficiency （SE） value increased from 1.54 to 23.3 dB.展开更多
Carbon fiber(C_(f))reinforced pyrolytic carbon(PyC)composites simultaneously possessing robust mechanical strength,excellent friction performances and outstanding anti-ablation properties are demanded for advanced aer...Carbon fiber(C_(f))reinforced pyrolytic carbon(PyC)composites simultaneously possessing robust mechanical strength,excellent friction performances and outstanding anti-ablation properties are demanded for advanced aerospace applications.Efficient architecture design and optimization of composites are promi-nent yet remain high challenging for realizing the above requirements.Herein,binary reinforcements of networked silicon nitride nanowires(Si_(3)N_(4) nws)and interconnected graphene(GE)have been successfully constructed into C f/PyC by precursor impregnation-pyrolysis and chemical vapor deposition.Notably,net-worked Si_(3)N_(4) nws are uniformly distributed among the carbon fibers,while interconnected GE is firmly rooted on the surface of both networked Si_(3)N_(4) nws and carbon fibers.In the networked Si_(3)N_(4) nws and interconnected GE reinforced C_(f)/PyC,networked Si_(3)N_(4) nws significantly boost the cohesion strength of PyC,while GE markedly improves the interface bonding of both Si_(3)N_(4) nws/PyC and fiber/PyC.Benefiting from the synergistic reinforcement effect of networked Si_(3)N_(4) nws and interconnected GE,the C_(f)/PyC have a prominent enhancement in mechanical(shear and compressive strengths increased by 119.9% and 52.84%,respectively)and friction(friction coefficient and wear rate reduced by 25.40% and 60.10%,respectively)as well as anti-ablation(mass ablation rate and linear ablation rate decreased by 71.25% and 63.01%,respectively).This present strategy for networked Si_(3)N_(4) nws and interconnected GE reinforced C_(f)/PyC provides a dominant route to produce mechanically robust,frictionally resisting and ablatively resistant materials for use in advanced aerospace applications.展开更多
Recycling of carbon fiber reinforced composites is important for sustainable development and the circular economy.Despite the use of dynamic chemistry,developing high-strength recyclable CFRPs remains a major challeng...Recycling of carbon fiber reinforced composites is important for sustainable development and the circular economy.Despite the use of dynamic chemistry,developing high-strength recyclable CFRPs remains a major challenge due to the mutual exclusivity between the dynamic and mechanical properties of materials.Here,we developed a high-strength recyclable epoxy resin(HREP)based on dynamic dithioacetal covalent adaptive network using diglycidyl ether bisphenol A(DGEBA),pentaerythritol tetra(3-mercapto-propionate)(PETMP),and vanillin epoxy resin(VEPR).At high temperatures,the exchange reaction of thermally activated dithioacetals accelerated the rearrangement of the network,giving it significant reprocessing ability.Moreover,HREP exhibited excellent solvent resistance due to the increased cross-linking density.Using this high-strength recyclable epoxy resin as the matrix and carbon fiber modified with hyperbranched ionic liquids(HBP-AMIM+PF6-)as the reinforcing agent,high performance CFRPs were successfully prepared.The tensile strength,interfacial shear strength(IFSS)and interlaminar shear strength(ILSS)of the optimized formulation(HREP20/CF-HBPPF6)were 1016.1,70.8 and 76.0 MPa,respectively.In addition,the CFRPs demonstrated excellent solvent and acid/alkali-resistance.The CFRPs could completely degrade within 24 h in DMSO at 140℃,and the recycled CF still maintained the same tensile strength and ILSS as the original after multiple degradation cycles.展开更多
Carbon fibers（CFs） were coated with a nickel-phosphorus（Ni-P） film using an electroless plating process. The morphology, elemental composition and phases in the coating layer of the CFs were investigated by scanni...Carbon fibers（CFs） were coated with a nickel-phosphorus（Ni-P） film using an electroless plating process. The morphology, elemental composition and phases in the coating layer of the CFs were investigated by scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS） and X-ray diffraction（XRD）, respectively. Wet paper-making method was used to prepare nickle coated carbon fiber paper（NCFP）. Vacuum assisted infusion molding process（VAIMP） was employed to manufacture the NCFP reinforced epoxy composites, and carbon fiber paper（CFP） reinforced epoxy composites were also produced as a comparison. Electromagnetic interference（EMI） shielding properties of the composites were measured in the 3.22-4.9 GHz frequency range using waveguide method. Both NCFP and CFP reinforced epoxy composites of 0.5 mm thickness exhibited high EMI shielding effectiveness（SE） at 8wt% fiber content, 35 d B and 30 d B, respectively, and reflection was the dominant shielding mechanism.展开更多
Coal is a versatile energy resource and was a driver of the industrial revolution that transformed the economies of Europe and North America and the trajectory of civilization.In this work,a technoeconomic analysis wa...Coal is a versatile energy resource and was a driver of the industrial revolution that transformed the economies of Europe and North America and the trajectory of civilization.In this work,a technoeconomic analysis was performed for a coal-to-carbonfiber manufacture process developed at the University of Kentucky’s Center for Applied Energy Research.According to this process,coal,with decant oil as the solvent,was converted to mesophase pitch via solvent extraction,and the mesophase pitch was subsequently converted to carbon fiber.The total cost to produce carbon fibers from coal and decant oil via the solvent extraction process was estimated to be$11.50/kg for 50,000-tow pitch carbon fiber with a production volume of 3750 MT/year.The estimated carbon fiber cost was significantly lower than the current commercially available PAN-based carbon fiber price($20–$30/kg).With decant oil recycling rates of 50%and 70%in the solvent extraction process,the manufacturing cost of carbon fiber was estimated to be$9.90/kg and$9.50/kg of carbon fiber,respectively.A cradle-to-gate energy assessment revealed that carbon fiber derived from coal exhibited an embodied energy of 510 MJ/kg,significantly lower than that of conventionally produced carbon fiber from PAN.This notable difference is primarily attributed to the substantially higher conversion rate of coal-based mesophase pitch fibers into carbon fiber,surpassing PAN fibers by 1.6 times.These findings indicate that using coal for carbon fiber production through solvent extraction methods could offer a more energy-efficient and cost-competitive alternative to the traditional PAN based approach.展开更多
Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechani...Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechanical properties of carbon fibers, and therefore affect the overall performance of pultruded composites. This study systematically investigated the influence of PAN precursor properties on the degree of graphitization, surface morphology and mechanical properties of carbon fibers by regulating the molecular weight distribution, stretching ratio and impurity content of PAN precursor, and analyzed the mechanism of action of carbon fiber properties on the interfacial bonding strength and tensile/ bending properties of composites in combination with the pultrusion process. The results showed that when the filament stretchability was increased to 4.5 times, the axial orientation of carbon fibers increased by 18% and the tensile strength reached 520 MPa;Filaments with impurity content below 0.3% increase carbon fiber yield by 5.2% and interlaminar shear strength of composites by 23%. This study provides a theoretical basis for raw material screening and process optimization of high-performance carbon fibers and their composites.展开更多
This study proposes a pre-strain optimization strategy for carbon fiber structural lithium-ion battery(SLIB) composites to inhibit the interfacial debonding between carbon fibers and solid-state electrolytes due to fi...This study proposes a pre-strain optimization strategy for carbon fiber structural lithium-ion battery(SLIB) composites to inhibit the interfacial debonding between carbon fibers and solid-state electrolytes due to fiber lithiation. Through an analytical shear-lag model and finite element simulations, it is demonstrated that applying tensile pre-strain to carbon fibers before electrode assembly effectively reduces the interfacial shear stress, thereby suppressing debonding. However, the excessive pre-strain can induce the interfacial damage in the unlithiated state, necessitating careful control of the pre-strain within a feasible range. This range is influenced by electrode material properties and geometric parameters. Specifically, the electrodes with the higher solid-state electrolyte elastic modulus and larger electrolyte volume fraction exhibit more significant interfacial damage, making pre-strain application increasingly critical. However, these conditions also impose stricter constraints on the feasible pre-strain range. By elucidating the interplay between pre-strain, material properties, and geometric factors, this study provides valuable insights for optimizing the design of carbon fiber SLIBs.展开更多
Polyacrylonitrile-based commercial carbon fibers(CFs)have garnered significant attention in mechanical applications because of their exceptional mechanical properties.However,their functional versatility relies heavil...Polyacrylonitrile-based commercial carbon fibers(CFs)have garnered significant attention in mechanical applications because of their exceptional mechanical properties.However,their functional versatility relies heavily on the structural intricacies of duplex carbon layers.Current modification approaches,though effective,are encumbered by complexity and cost,limiting widespread adoption across diverse fields.We herein present a straightforward modification strategy centered on regulating carbon layers to unlock the multifunctional potential of CFs.Our method leverages two common anions,Cl^(-)and SO_(4)^(2-),to facilitate oxidation reactions in CFs under robust alkali and high voltage conditions.Cl^(-)effectively activates carbon layers,while SO_(4)^(2-)facilitates layer movement.The electrocatalytic activities of the resultant CFs are enhanced,with state-of-the-art performance as supercapacitors and exceptional stability.Moreover,our approach achieves a groundbreaking milestone by bending and fusing CFs without using binders.This breakthrough can reduce the manufacturing costs of CF-based products.It also facilitates the development of novel microelectronic devices.展开更多
Carbon fiber-reinforced composites(CFRCs)have a wide range of applications in the aerospace,automotive,and energy sectors.A higher specific strength-to-weight ratio is desired in high-performance applications.The fail...Carbon fiber-reinforced composites(CFRCs)have a wide range of applications in the aerospace,automotive,and energy sectors.A higher specific strength-to-weight ratio is desired in high-performance applications.The failure mechanism of CFRCs involves multiscale phenomena,such as failure that can occur at the matrix,fibers,interface,layers,lamina,and laminates.When an impactor hits the CFRCs,the design involves analyzing each of these stages to prevent failure and optimize the properties of CFRCs under various loading conditions.A numerical model was employed to predict the fracture toughness of CFRCs with varying weight fractions and orientations.Finite Element Analysis(FEA)was conducted at the fiber level on a micrometer scale for the CFRCs against an impact loading.Epoxy composite samples at the coupon level were prepared using the hand layup technique with carbon fibers laid at three different angles,i.e.,longitudinal,transverse,and angular orientations.Samples with five different weight percentages of carbon fibers were prepared and investigated.An Izod impact tester was used to fracture the samples and characterize the energy absorption.The fractured surfaces were observed with a scanning electron microscope(SEM).The numerical and experimental results show that crack propagation is inhibited at higher loading fractions at an angular orientation by creating obstacles for the crack to propagate and arresting the dislocation motion.The fractography analysis through a scanning electron microscope exhibits how the angular orientations of the fibers are reoriented after fracture to prevent further crack propagation.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:51971065Innovation Program of Shanghai Municipal Education Commission,Grant/Award Number:2019-01-07-00-07-E00028。
文摘SnO_(2) has been extensively investigated as an anode material for sodium-ion batteries(SIBs)and potassium-ion batteries(PIBs)due to its high Na/K storage capacity,high abundance,and low toxicity.However,the sluggish reaction kinetics,low electronic conductivity,and large volume changes during charge and discharge hinder the practical applications of SnO_(2)-based electrodes for SIBs and PIBs.Engineering rational structures with fast charge/ion transfer and robust stability is important to overcoming these challenges.Herein,S-doped SnO_(2)(S-SnO_(2))quantum dots(QDs)(≈3 nm)encapsulated in an N,S codoped carbon fiber networks(S-SnO_(2)-CFN)are rationally fabricated using a sequential freeze-drying,calcination,and S-doping strategy.Experimental analysis and density functional theory calculations reveal that the integration of S-SnO_(2) QDs with N,S codoped carbon fiber network remarkably decreases the adsorption energies of Na/K atoms in the interlayer of SnO_(2)-CFN,and the S doping can increase the conductivity of SnO_(2),thereby enhancing the ion transfer kinetics.The synergistic interaction between S-SnO_(2) QDs and N,S codoped carbon fiber network results in a composite with fast Na+/K+storage and extraordinary long-term cyclability.Specifically,the S-SnO_(2)-CFN delivers high rate capacities of 141.0 mAh g^(−1) at 20 A g^(−1) in SIBs and 102.8 mAh g^(−1) at 10 A g^(−1) in PIBs.Impressively,it delivers ultra-stable sodium storage up to 10,000 cycles at 5 A g^(−1) and potassium storage up to 5000 cycles at 2 A g^(−1).This study provides insights into constructing metal oxide-based carbon fiber network structures for high-performance electrochemical energy storage and conversion devices.
文摘A new production line has officially started operating at a green energy industrial park in the Shanxi Yungang Economic Development Zone.Tens of thousands of hair-thin black filaments flow uniformly like gleaming dark rivers from the winding machines.The Institute of Coal Chemistry of the Chinese Academy of Sciences(CAS)developed T1000-grade high-performance carbon fiber here,and it has fully independent intellectual property rights.“It took us 20 years to go from having‘no grain to cook’to achieving‘high-end iteration,’”said Zhang Shouchun,Deputy Director of the Institute of Coal Chemistry,CAS,and project leader.Behind this striking black thread lies an arduous,persistent campaign of material innovation.
基金supported by the National Natural Science Foundation of China(No.52373085)Natural Science Foundation of Hubei Province(No.2023AFB828)+4 种基金Innovative Team Program ofNatural Science Foundation of Hubei Province(No.2023AFA027)Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2023433)Natural Science Foundation of Shanxi Province(Grant No.20210302124128)Open Fund for Hubei Key Laboratory of Digital Textile Equipment(No.DTL 2023022)the Open Fund for National Local Joint Laboratory for Advanced Textile Processing and Clean Production(No.17)。
文摘Carbon fibers(CFs)are widely used in cutting-edge and civilian fields due to their excellent comprehensive properties such as high strength and high modulus,superior corrosion and friction resistances,excellent thermal stability,light weight,and high electrical conductivity.However,their natural ultra-black appearance is difficult to meet the aesthetic needs of today's civilian sector and the need for optical stealth in the military field.In addition,conventional coloring methods are difficult to effectively adhere to CF surfaces due to high crystallinity and highly inert surface caused by their graphite-like structure.In this work,inspired by the nacre structural color of pearls,colored CFs with 1D photonic crystal structure are prepared by cyclically depositing amorphous(Al_(2)O_(3)+TiO_(2))layers on the surface of carbon CFs through atomic layer deposition(ALD).The obtained CFs exhibit brilliant colors and excellent environmental durability in extreme environments.Moreover,the colored CFs also exhibit high EMI shielding effectiveness(45 dB)and optical stealth properties,which can be used in emerging optical devices and electromagnetic and optical stealth equipment.
文摘Carbon fiber-reinforced plastics (CFRPs) possess pronounced anisotropic properties, necessitating advancements in through-thickness electrical conductivity and other functionalities without compromising mechanical integrity. MXenes, as an emerging family of two-dimensional nanomaterials, have demonstrated significant potential for enhancement modification in this area. However, achieving uniform distribution and effective utilization on a large scale with low filler content has posed a significant challenge. Herein, a highly lightweight, flexible, and functional Ti_(3)C_(2)T_(x)/ poly(3,4-ethylene-dioxythiophene) poly (styrene sulfonate) (PEDOT: PSS) /Ammonium polyphosphate (APP) reclaimed carbon fiber (rCF) veil reinforced plastics (MPA-rCFRPs) was fabricated through large-scale vacuum-assisted filtration and autoclave technology. The modified MPA-rCFRPs have exhibited substantial improvements in electromagnetic shielding with MXene additive amounts as low as 0.24 %-1.07 %, increasing the electro-magnetic interference shielding effectiveness (EMI SE) to 87.12 dB, improved by 350.02 %. Remarkably, the through-thickness electrical conductivity of MPA-rCFRPs exhibited a 767.14 % improvement, escalating from 19.73 S/m to 151.41 S/m. Meanwhile, the modified composites have exhibited enhanced photothermal, electrothermal, and flame-retardant properties, and the above improvements have not shown a significant impact on the mechanical properties of the material. This work represents a practical solution for the construction of large-scale MXene-based carbon fiber composites and opens the door to functional reutilization of rCF materials.
基金financially supported by the National Natural Science Foundation of China(No.51972045)the Foundation of Yangtze Delta Region Institute(HuZhou)of UESTC(No.U03210030)+1 种基金the Fundamental Research Funds for Chinese Central Universities,China(No.ZYGX2019J025)Sichuan Science and Technology Program(No.2021YFG0373)。
文摘With the rapid development of electronic information technology,the waste electromagnetic radiation generated by the wireless and various other electronic devices has caused serious harm to human health.The development of high-efficiency flexible electromagnetic interference(EMI)shielding materials has become one of the most effective ways to mitigate the increasingly serious problem of electromagnetic pollution.Flexible carbon fiber composites possess most of the physical requirements needed for EMI shielding applications,including high electrical conductivity,large specific surface area,light weight,flexibility,porous structure,and adjustable physical and chemical properties,and various morphology of carbon fibers-based composites applied EMI.In this review,the primary EMI shielding mechanism of carbonfiber-based materials is presented.Since carbon fiber suffers from a low absorption efficiency when used for EMI shielding by itself,it is usually combined with additional EMI filling materials.Therefore,the methods of adding EMI filler materials to the carbon fiber framework and the influence of different fillers on the EMI shielding performance are also discussed.In addition,the novel structural designs of flexible carbon fiber-based EMI shielding materials,including fiber orientation,core-shell structure,and multilayer heterostructure,are summarized in terms of their classification,which includes composites with metal,polymer,nano-carbon,and MXenes.The review concludes with a brief discussion of the challenges,research directions,and future prospects of carbon-fiber-based EMI shielding materials.
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.
文摘Micro-coiled chiral carbon fibers are modified by nano-Ni. X-ray diffraction （XRD） and scanning electron microscopy （SEM） are used to compare the composition and morphology of the unmodified and the modified fibers. The results show that electromagnetism parameters of the modified are different from those of the unmodified. After modification by nano-Ni, the micro-coiled chiral carbon fibers have decreased permittivity and electrical loss. The permeability and magnetic loss of the modified carbon fibers become larger than those of the unmodified ones. Moreover, the modification of unmodified chiral carbon fibers into the modified is much like changing hollow electric windings into those with magnetic cores inside. The modifier intensifies the cross polarization of the chiral carbon fibers and makes the permittivity and the permeability get closer to each other which improves the matching performance and enhances absorbability of coatings. In the range of 6-18 GHz, the reflectivity of the coating is 6-8dB and the bandwidth is 12 GHz. The area density of the coating is below 3 kg/m^2.
基金National Natural Science Foundation of China,Grant/Award Numbers:32171717,32271814Natural Science Foundation of Tianjin Municipality,Grant/Award Numbers:24JCJQJC00030,22JCYBJC01560,23JCZDJC00630China Postdoctoral Science Foundation,Grant/Award Number:2023M740562。
文摘Carbon fibers(CFs)with notable comprehensive properties,such as light weight,high specific strength,and stiffness,have garnered considerable interest in both academic and industrial fields due to their diverse and advanced applications.However,the commonly utilized precursors,such as polyacrylonitrile and pitch,exhibit a lack of environmental sustainability,and their costs are heavily reliant on fluctuating petroleum prices.To meet the substantial market demand for CFs,significant efforts have been made to develop cost-effective and sustainable CFs derived from biomass.Lignin,the most abundant polyphenolic compound in nature,is emerging as a promising precursor which is well-suited for the production of CFs due to its renewable nature,low cost,high carbon content,and aromatic structures.Nevertheless,the majority of lignin raw materials are currently derived from pulping and biorefining industrial by-products,which are diverse and heterogeneous in nature,restricting the industrialization of lignin-derived CFs.This review classifies fossil-derived and biomass-derived CFs,starting from the sources and chemical structures of raw lignin,and outlines the preparation methods linked to the performance of lignin-derived CFs.A comprehensive discussion is presented on the relationship between the structural characteristics of lignin,spinning preparation,and structure-morphology-property of ligninderived CFs.Additionally,the potential applications of these materials in various domains,including energy,catalysis,composites,and other advanced products,are also described with the objective of spotlighting the unique merits of lignin.Finally,the current challenges faced and future prospects for the advancement of lignin-derived CFs are proposed.
基金supported by Yunnan Major Scientific and Technological Projects(No.202202AG050005)Yunnan Fundamental Research Projects(No.202101BE070001-001).
文摘The ACF adsorbent with high Cu loading was treated with dielectric barrier discharge plasma to mitigate the negative effects of high Cu loading and enhance PH_(3)and H_(2)S adsorption and oxidation.Bruno-Emmett-Taylor(BET)result showed that the specific surface area of the adsorbent after air plasma modification was almost three times that before modification.X-ray photoelectron spectroscopy(XPS)findings revealed that the amino group was added to the adsorbent's surface,increasing lattice oxygen and chemisorbed oxygen.The adsorbent's large specific surface area,excellent surface active oxygen,and abundance of basic groups facilitate PH_(3)and H_(2)S adsorption and oxidation.The scanning electron microscopy showed that air plasma modification exposed more active components and uniformly dispersed them on the surface of adsorbent,thereby improving the adsorption performance.Activity evaluation results showed that the adsorbent has the best ability to capture PH_(3)and H_(2)S after being modified by air plasma at 4 kV voltage for 10 min.The adsorbent's breakthrough ability at high space velocity(WHSV:60,000 h^(−1))is 190 mg P/g and 146 mg S/g,respectively,which is 74%and 60%greater than that before modification.This is a great improvement over previous studies.In addition,the possible mechanism of adsorbent deactivation was proposed.
基金financially supported by the National Natural Science Foundation of China(Nos.51971111,22005148)the Natural Science Foundation of Jiangsu Province(No.BK20200766)。
文摘To reduce electromagnetic(EM)wave interference pollution,in this work,carbon fibers@Co-ZIFs derivations(CFZD)as an advanced EM wave absorbing material was successfully prepared.The yolk-shell structure of the magnetic metal particles generated a large amount of contact area,facilitating the interface polarization and relaxation.As a result,the optimized sample delivers a maximum reflection loss(RL)value of-19.2 d B with a bandwidth of 2.6 GHz at a small thickness of 1.3 mm.Additionally,ANSYS Electronics Desktop 2018(HFSS)was used to simulate the radar cross section(RCS)reduction in practical application based on these composites.The RCS values of composite coatings are less than-10 d B m^(2) at the range of-90°<theta<-10°and 10°<theta<90°,which indicate the effective reduction of the radar reflection signal by the composite coatings.The work is of reference significance for preparing great absorbing materials and designing absorbing coatings by combining simulation method.
基金supported by the Science and Technology Development Program of Jilin Province(No.20240101122JC)and(No.20240101143JC)the Key Scientific and Technological Research and Development Projects of Jilin Provincial Science and Technology Department(Grant Number 20230201108GX)。
文摘Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are known for their unique compact structure;they are not only lightweight but also strong.In this study,an in-depth look at owl feathers was made and it found that owl feathers not only have the macro branches structure between feather shafts and branches but also have fine feather structures on the branches.The presence of these fine feather structures increases the specific surface area of the plume branches and allows neighboring plume branches to hook up with each other,forming an effective mechanical interlocking structure.These structures bring owl feathers excellent mechanical properties.Inspired by the natural structure of owl feathers,a weaving technique and a sizing process were combined to prepare bionic Carbon Fiber(CF)fabrics and then to fabricate the bionic CFRP with structural characteristics similar to owl feathers.To evaluate the effect of the fine feather structure on the mechanical properties of CFRP,a mechanical property study on CFRP with and without the fine feather imitation structure were conducted.The experimental results show that the introduction of the fine feather branch structure enhance the mechanical properties of CFRP significantly.Specifically,the tensile strength of the composites increased by 6.42%and 13.06%and the flexural strength increased by 8.02%and 16.87%in the 0°and 90°sample directions,respectively.These results provide a new design idea for the improvement of the mechanical properties of the CFRP,promoting the application of CFRP in engineering fields,such as automotive transportation,rail transit,aerospace,and construction.
文摘Combined nitric acid oxidation method and polyaniline （PANI）-coated method were applied to modify the surface properties of short carbon fibers （SCF）. The electrical and mechanical properties of acrylic coatings with 50 wt pct PANI-coated carbon fiber were investigated by using scanning electron microscope （SEM）, UV-Vis spectrophotometer, four-probe method and the coaxial cable method. The results of the pH measurement and XPS （X-ray photoelectron spectroscopy） patterns showed that the oxygen functional groups, such as -OH and -COOH, were attached on the carbon fiber surfaces after oxidation treatment. The XPS analysis of PANl-coated oxidized SCF （PAOSCF） revealed that PANI may bond on the surface of oxidized SCF with chemical bonds. SEM images and surface roughness analyses showed that PANl-coated layer changed the surface morphology. Compared with SCF/acrylic coating, the surface resistivity of PAOSCF/acrylic coating decreased from17.1 to 5.3 Ω/sq and the shielding efficiency （SE） value increased from 1.54 to 23.3 dB.
基金financially supported by the National Natural Science Foundation of China(No.51872232)the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(No.136-QP-2015)+4 种基金the“111”project of China(No.B08040)the National Training Program of Innovation and Entrepreneurship for Undergraduates(No.S202010699336)the Joint Funds of the National Natural Science Foundation of China(No.U21B2067)the Key Scientific and Technological Innovation Research Team of Shaanxi Province(No.2022TD-31)the Key R&D Program of Shaanxi Province(No.2021ZDLGY14-04).
文摘Carbon fiber(C_(f))reinforced pyrolytic carbon(PyC)composites simultaneously possessing robust mechanical strength,excellent friction performances and outstanding anti-ablation properties are demanded for advanced aerospace applications.Efficient architecture design and optimization of composites are promi-nent yet remain high challenging for realizing the above requirements.Herein,binary reinforcements of networked silicon nitride nanowires(Si_(3)N_(4) nws)and interconnected graphene(GE)have been successfully constructed into C f/PyC by precursor impregnation-pyrolysis and chemical vapor deposition.Notably,net-worked Si_(3)N_(4) nws are uniformly distributed among the carbon fibers,while interconnected GE is firmly rooted on the surface of both networked Si_(3)N_(4) nws and carbon fibers.In the networked Si_(3)N_(4) nws and interconnected GE reinforced C_(f)/PyC,networked Si_(3)N_(4) nws significantly boost the cohesion strength of PyC,while GE markedly improves the interface bonding of both Si_(3)N_(4) nws/PyC and fiber/PyC.Benefiting from the synergistic reinforcement effect of networked Si_(3)N_(4) nws and interconnected GE,the C_(f)/PyC have a prominent enhancement in mechanical(shear and compressive strengths increased by 119.9% and 52.84%,respectively)and friction(friction coefficient and wear rate reduced by 25.40% and 60.10%,respectively)as well as anti-ablation(mass ablation rate and linear ablation rate decreased by 71.25% and 63.01%,respectively).This present strategy for networked Si_(3)N_(4) nws and interconnected GE reinforced C_(f)/PyC provides a dominant route to produce mechanically robust,frictionally resisting and ablatively resistant materials for use in advanced aerospace applications.
基金financially supported by the National Natural Science Foundation of China(Nos.U23A2069 and 51403242)the Natural Science Foundation of Hubei Province(No.2024AFB800)+5 种基金the Fundamental Research Funds for the Central Universities,South-Central Minzu University(Nos.CZY23017 and CZD24001)the Innovation Group of National Ethnic Affairs Commission of China(No.MZR20006)the Fund for Academic Innovation Teams of South-Central Minzu University(No.XTZ24012)Scientific Research Platforms of South-Central Minzu University(No.PTZ24013)the Open Fund for Key Lab of Guangdong High Property and Functional Macromolecular Materials,China(No.20240007)State Key Laboratory of New Textile Materials and Advanced Processing Technologies(No.FZ20230012)。
文摘Recycling of carbon fiber reinforced composites is important for sustainable development and the circular economy.Despite the use of dynamic chemistry,developing high-strength recyclable CFRPs remains a major challenge due to the mutual exclusivity between the dynamic and mechanical properties of materials.Here,we developed a high-strength recyclable epoxy resin(HREP)based on dynamic dithioacetal covalent adaptive network using diglycidyl ether bisphenol A(DGEBA),pentaerythritol tetra(3-mercapto-propionate)(PETMP),and vanillin epoxy resin(VEPR).At high temperatures,the exchange reaction of thermally activated dithioacetals accelerated the rearrangement of the network,giving it significant reprocessing ability.Moreover,HREP exhibited excellent solvent resistance due to the increased cross-linking density.Using this high-strength recyclable epoxy resin as the matrix and carbon fiber modified with hyperbranched ionic liquids(HBP-AMIM+PF6-)as the reinforcing agent,high performance CFRPs were successfully prepared.The tensile strength,interfacial shear strength(IFSS)and interlaminar shear strength(ILSS)of the optimized formulation(HREP20/CF-HBPPF6)were 1016.1,70.8 and 76.0 MPa,respectively.In addition,the CFRPs demonstrated excellent solvent and acid/alkali-resistance.The CFRPs could completely degrade within 24 h in DMSO at 140℃,and the recycled CF still maintained the same tensile strength and ILSS as the original after multiple degradation cycles.
基金Funded by the National Natural Science Foundation of China(No.51373129)
文摘Carbon fibers（CFs） were coated with a nickel-phosphorus（Ni-P） film using an electroless plating process. The morphology, elemental composition and phases in the coating layer of the CFs were investigated by scanning electron microscopy（SEM）, energy dispersive spectroscopy（EDS） and X-ray diffraction（XRD）, respectively. Wet paper-making method was used to prepare nickle coated carbon fiber paper（NCFP）. Vacuum assisted infusion molding process（VAIMP） was employed to manufacture the NCFP reinforced epoxy composites, and carbon fiber paper（CFP） reinforced epoxy composites were also produced as a comparison. Electromagnetic interference（EMI） shielding properties of the composites were measured in the 3.22-4.9 GHz frequency range using waveguide method. Both NCFP and CFP reinforced epoxy composites of 0.5 mm thickness exhibited high EMI shielding effectiveness（SE） at 8wt% fiber content, 35 d B and 30 d B, respectively, and reflection was the dominant shielding mechanism.
基金sponsored by the US Department of Energy Fossil Energy and Carbon Management Program,project FEAA157 under contract DE-AC05-00OR22725 with UTBattelle,LLC.
文摘Coal is a versatile energy resource and was a driver of the industrial revolution that transformed the economies of Europe and North America and the trajectory of civilization.In this work,a technoeconomic analysis was performed for a coal-to-carbonfiber manufacture process developed at the University of Kentucky’s Center for Applied Energy Research.According to this process,coal,with decant oil as the solvent,was converted to mesophase pitch via solvent extraction,and the mesophase pitch was subsequently converted to carbon fiber.The total cost to produce carbon fibers from coal and decant oil via the solvent extraction process was estimated to be$11.50/kg for 50,000-tow pitch carbon fiber with a production volume of 3750 MT/year.The estimated carbon fiber cost was significantly lower than the current commercially available PAN-based carbon fiber price($20–$30/kg).With decant oil recycling rates of 50%and 70%in the solvent extraction process,the manufacturing cost of carbon fiber was estimated to be$9.90/kg and$9.50/kg of carbon fiber,respectively.A cradle-to-gate energy assessment revealed that carbon fiber derived from coal exhibited an embodied energy of 510 MJ/kg,significantly lower than that of conventionally produced carbon fiber from PAN.This notable difference is primarily attributed to the substantially higher conversion rate of coal-based mesophase pitch fibers into carbon fiber,surpassing PAN fibers by 1.6 times.These findings indicate that using coal for carbon fiber production through solvent extraction methods could offer a more energy-efficient and cost-competitive alternative to the traditional PAN based approach.
文摘Polyacrylonitrile (PAN) precursor is a core precursor for the preparation of high-performance carbon fibers. Its unique chemical structure and physical properties directly contributes to the microstructure and mechanical properties of carbon fibers, and therefore affect the overall performance of pultruded composites. This study systematically investigated the influence of PAN precursor properties on the degree of graphitization, surface morphology and mechanical properties of carbon fibers by regulating the molecular weight distribution, stretching ratio and impurity content of PAN precursor, and analyzed the mechanism of action of carbon fiber properties on the interfacial bonding strength and tensile/ bending properties of composites in combination with the pultrusion process. The results showed that when the filament stretchability was increased to 4.5 times, the axial orientation of carbon fibers increased by 18% and the tensile strength reached 520 MPa;Filaments with impurity content below 0.3% increase carbon fiber yield by 5.2% and interlaminar shear strength of composites by 23%. This study provides a theoretical basis for raw material screening and process optimization of high-performance carbon fibers and their composites.
基金supported by the National Natural Science Foundation of China(Nos.12172205,12072183,12102244,and 12472174)。
文摘This study proposes a pre-strain optimization strategy for carbon fiber structural lithium-ion battery(SLIB) composites to inhibit the interfacial debonding between carbon fibers and solid-state electrolytes due to fiber lithiation. Through an analytical shear-lag model and finite element simulations, it is demonstrated that applying tensile pre-strain to carbon fibers before electrode assembly effectively reduces the interfacial shear stress, thereby suppressing debonding. However, the excessive pre-strain can induce the interfacial damage in the unlithiated state, necessitating careful control of the pre-strain within a feasible range. This range is influenced by electrode material properties and geometric parameters. Specifically, the electrodes with the higher solid-state electrolyte elastic modulus and larger electrolyte volume fraction exhibit more significant interfacial damage, making pre-strain application increasingly critical. However, these conditions also impose stricter constraints on the feasible pre-strain range. By elucidating the interplay between pre-strain, material properties, and geometric factors, this study provides valuable insights for optimizing the design of carbon fiber SLIBs.
基金support from the Key-Area Research and Development Program of Guangdong Province(2019B111107002)the National Natural Science Foundation of China(52478266 and 52108231)+1 种基金the Basic and Applied Basic Research Fund of Guangdong Province(2023A1515012150 and 2023A1515012409)the Shenzhen Science and Technology Innovation Program(20220810140230001 and 20220810160453001).
文摘Polyacrylonitrile-based commercial carbon fibers(CFs)have garnered significant attention in mechanical applications because of their exceptional mechanical properties.However,their functional versatility relies heavily on the structural intricacies of duplex carbon layers.Current modification approaches,though effective,are encumbered by complexity and cost,limiting widespread adoption across diverse fields.We herein present a straightforward modification strategy centered on regulating carbon layers to unlock the multifunctional potential of CFs.Our method leverages two common anions,Cl^(-)and SO_(4)^(2-),to facilitate oxidation reactions in CFs under robust alkali and high voltage conditions.Cl^(-)effectively activates carbon layers,while SO_(4)^(2-)facilitates layer movement.The electrocatalytic activities of the resultant CFs are enhanced,with state-of-the-art performance as supercapacitors and exceptional stability.Moreover,our approach achieves a groundbreaking milestone by bending and fusing CFs without using binders.This breakthrough can reduce the manufacturing costs of CF-based products.It also facilitates the development of novel microelectronic devices.
基金supported by the University of Texas(UT)system STARs grant,Semester Undergraduate Research Experience(SURE)program at the College of Engineering at the University of Texas Permian Basin(UTPB)EM-STEP(Engineering Minority Student Engagement Project)at UTPB College of Engineering,funded by Department of Education.
文摘Carbon fiber-reinforced composites(CFRCs)have a wide range of applications in the aerospace,automotive,and energy sectors.A higher specific strength-to-weight ratio is desired in high-performance applications.The failure mechanism of CFRCs involves multiscale phenomena,such as failure that can occur at the matrix,fibers,interface,layers,lamina,and laminates.When an impactor hits the CFRCs,the design involves analyzing each of these stages to prevent failure and optimize the properties of CFRCs under various loading conditions.A numerical model was employed to predict the fracture toughness of CFRCs with varying weight fractions and orientations.Finite Element Analysis(FEA)was conducted at the fiber level on a micrometer scale for the CFRCs against an impact loading.Epoxy composite samples at the coupon level were prepared using the hand layup technique with carbon fibers laid at three different angles,i.e.,longitudinal,transverse,and angular orientations.Samples with five different weight percentages of carbon fibers were prepared and investigated.An Izod impact tester was used to fracture the samples and characterize the energy absorption.The fractured surfaces were observed with a scanning electron microscope(SEM).The numerical and experimental results show that crack propagation is inhibited at higher loading fractions at an angular orientation by creating obstacles for the crack to propagate and arresting the dislocation motion.The fractography analysis through a scanning electron microscope exhibits how the angular orientations of the fibers are reoriented after fracture to prevent further crack propagation.
