Carbon Fiber Cloth Research Articles

Porous structural battery composite for coordinated integration of mechanical and electrical functionalities

AbstractStructural battery composites (SBCs) represent an emerging multifunctional technology in which materials functionalized with energy storage capabilities are used to build load‐bearing structural components. However, due to the liquid electrolyte contamination in structural battery electrolyte (SBE) and the large volume expansion of active battery materials, the poor interlayer interfacial in multilayer SBCs often causes difficulties in practical use. In this study, a new porous LiFePO4‐graphite SBC is designed and fabricated by independently distributing battery materials and resin matrix on carbon fiber fabric in pattern lattice form to prepare electrodes prepreg. The cured porous composite framework supports the load‐bearing function while limiting the electrochemical reaction in liquid electrolyte within lattices. The electrodes show reversible electric resistance after 3000 bending cycles with radius as small as 10 mm. The mechanical properties enhance significantly with tensile strength of 486.1 MPa and Young's modulus of 9.1 GPa compared to that with a liquid–solid biphasic mixed SBE structure. The SBC also exhibits a favorable capacity of 27.8 mAh/g at 0.1C. This straightforward integration path of mechanical and electrical functionalities is compatible with the manufacturing process of aerospace composite structures, which will provide an efficient and convenient energy supply solution for distributed electronics.Highlights A porous full‐cell structural battery composite (SBC) was designed and fabricated with prepregs. A suspension deposition and volatilization method was developed for robust battery material coating. Electrodes layer exhibited reversible electric resistance after 3000 tensile/bending cycles. The tensile strength and modulus increased significantly compared to the SBC with liquid–solid biphasic mixed structural battery electrolyte. Coordinated integration path was completely compatible with the manufacturing process of aerospace composite structures.

In Situ Microscopy of Fatigue-Loaded Embedded Transverse Layers of Cross-Ply Laminates: The Role of an Inhomogeneous Fiber Distribution

Composites with continuous fiber reinforcement offer excellent fatigue properties but are tedious to characterize due to anisotropy and the interplay of fatigue properties, processing conditions, and the constituents. The global fiber volume content can affect both monotonic and fatigue strength. This dependence can increase the necessary testing effort even when processing conditions and constituents remain identical. This work presents an in situ edge observation method, enabling light microscopy during loading. As a result, digital image correlation can be employed to study local strains at cracking sites on the scale of fiber bundles. The geometric influence on fatigue damage is examined in non-crimp fabrics of glass and carbon fibers. Two epoxy resins (one modified by irradiation) are investigated to verify the geometric influence under changed polymer properties. The microscopy-based image correlation revealed that damage forms at very low global strains of only 0.2–0.3% in glass fiber-reinforced epoxy laminates. For carbon fiber-reinforced epoxy, laminate cracking was found to emanate mainly from regions containing stitching fibers. Across both reinforcements, irradiation treatment led to delayed cracks, emanating from interfaces. This detailed analysis of the damage formation is used as a basis for proposed applications of the in situ strain information.

Outstanding enhancement of caproate production with microwave pyrolyzed highly reductive biochar addition

The integration of biochar into microbial Chain Elongation (CE) proves to be an effective tool of producing high-value bio-based products. This study innovatively applied biochar fabricated under microwave irradiation with carbon fiber cloth assistance into CE system. Results highlighted that microwave biochar achieved maximal CE efficiency yielding 8 g COD/L, with 3-fold increase to the blank group devoid of any biochar. Microwave biochar also obtained the highest substrate utilization rate of 94 %, while conventional biochar group recorded 90 % and the blank group was of 74 %. Mechanistic insights revealed that the reductive surface properties facilitated CE performance, which is relevant to fostering dominant genera of Parabacteroides, Bacteroides, and Macellibacteroides. By metagenomics, microwave biochar up-regulated functional genes and enzymes involved in CE process including ethanol oxidation, the reverse β-oxidation pathway, and the fatty acid biosynthesis pathway. This study effectively facilitated caproate production by utilizing a new microwave biochar preparation strategy.

Influence of bolt preload of anchors on bond-slip behavior of fiber fabric-steel interface

Bond-slip behavior is a common failure mode in steel structures reinforced with fiber fabric. Premature debonding of the fiber fabric significantly impacts the effectiveness of steel structure reinforcement. In this study, a gripping anchor is proposed to enhance the reliability of the interface between fiber fabric and steel plates. Experimental investigations were conducted to analyze the influence of anchor bolt preload on the double shear joint between fiber fabric and steel plates. 41 specimens were prepared and tested to explore the effects of parameters such as bolt preload, anchor position, number and type of fiber fabric layers, and bond length on load-bearing capacity. Comparative analyses were conducted on failure modes, ultimate loads, and stress-strain distributions of the specimens. Experimental results indicate that the position of the anchor has a minimal impact on the ultimate bearing capacity of the specimen. However, anchors positioned closer to the joint end exhibit lower ductility upon failure. A novel predictive model was developed to characterize the bond-slip behavior of preload applied to carbon fiber fabric and steel plates. The theoretical model of the ultimate bearing capacity in the yield stage fits well with the experimental results of specimens with three layers of carbon fiber fabric, with a difference range of 0.34 % to 14.97 % compared to actual results. This indicates that the model has high accuracy in predicting stress-strain and bearing capacity.

Z-scheme heterojunction of TiO2/NH2-MIL-125(Ti) growing on carbon fibers cloth: Photocatalytic degradation of tetracycline and toxicity analysis

Photocatalysis stands out as a promising and eco-friendly method for antibiotics removal, yet traditional photocatalysts, mainly in powder form, are often prone to detachment and loss, making them difficult to recycle and reuse. In this work, we address this challenge by using carbon fiber (CF) cloth with a large area as a carrier for catalysts. To improve the photocatalytic efficiency, we synthesized TiO2 nanorods on the surfaces of CF cloth and incorporate NH2-MIL-125 (Ti) on them, thus the Z-scheme heterojunctions CF/TiO2/NH2-MIL-125(Ti) was obtained. In order to fully understand the structural properties and performance advantages of CF/TiO2/NH₂-MIL-125 (Ti) composites, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray photoelectron spectroscopy (XPS), UV–visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), Brunauer-Emmett-Teller (BET), Mott-Schottky (M-S) and valence band X-ray photoelectron spectroscopy (VB-XPS). Due to the special electronic transmission path of the Z-scheme heterojunctions, the CF/TiO2/NH2-MIL-125(Ti) composite achieve 95.30 % degradation of tetracycline (TC) within 210 min. The composite also shows exceptional reusability, with a degradation rate of 93.55 % maintained even after four cycles. Finally, we proposed a pathway and catalytic process for the decomposition of TC by CF/TiO2/NH2-MIL-125(Ti) and performed toxicity assessments of TC and its precursors using T.E.S.T. software. This novel photocatalyst composite offers a green and efficient approach for treating antibiotic wastewater, presenting a significant advancement in environmental remediation strategies.

Graphene-based hierarchical structure for significantly enhancing thermal conductivity of composites with high mechanical reinforcement

Significant enhancement in out-of-plane thermal conductivity of carbon fiber/epoxy laminated composites without sacrificing mechanical strength is of great challenge for advanced composites. In this study, a novel graphene-based hierarchical structure was constructed by combining graphene foams (GrFs) with graphene nanoplatelets (GNPs) together and laminating with carbon fiber (CF) fabrics. The GrFs acted as thermally-conductive skeletons in bridging CF fabrics together to remarkably increase out-of-plane thermal conductivity of composites, while the GNPs were helpful to further increasing heat-transfer paths and effectively transferring stress between continuous CFs for high mechanical reinforcement. The hierarchical composites exhibited extremely high out-of-plane thermal conductivity of 2.64 W/m·K, increasing by 158.8 % than that of CF/Ep composites, and they also showed satisfactory tensile, flexural, and interlaminar shear strength. Such high performance is mainly due to the hierarchical structure, continuous heat-transfer paths, synergetic enhancement of GrFs with GNPs, and strong interfacial interactions between components for high-efficiency heat and stress transfer.

CFs-supported La-BiOIO3/Bi2O3 heterostructures via in situ growth strategies for efficiently removing diclofenac: Fermi level modulation, intermediates identification and radical mechanism

The charge transfer efficiency and the recyclability were still the potential factors limiting the widespread application of photocatalysts for pollutant removal. Herein, a novel design perspective for BiOIO3-based S-scheme heterojunction (La-BiOIO3/Bi2O3) with modulated Fermi level and enhanced internal electric field was proposed by in situ liquid-phase growth strategy. Meanwhile, the CFs@La-BiOIO3/Bi2O3 catalysts with high stability and easy recyclability were assembled based on industrial carbon fiber cloths, which can achieve efficiently photocatalytic removal of diclofenac (DCF, 95.5 %, 20 min) and bisphenol A (BPA, 100 %, 30 min) under simulated sunlight irradiation. The photocatalytic degradation rates of DCF were 52.8 and 12.4 times that of pure BiOIO3 and Bi2O3, respectively. The high specific surface area (39.74 m2·g−1) and suitable bandgap structure (2.74 eV) also demonstrated the excellence of the CFs@La-BiOIO3/Bi2O3 degradation system. Verification of heteroatom-driven electron rearrangement and charge migration route in heterostructure was performed through XPS analysis and Mott-Schottky experiments. Gaussian calculations, LC-MS, and toxicity assessments demonstrated that reactive oxygen species (ROS) such as ·O2− and ·OH selectively attacked the electronic groups of DCF and its intermediates, which combined with holes (h+) retained in the valence bands of Bi2O3 to synergistically achieve efficient degradation and detoxification of DCF. Finally, the charge migration mechanism for the photocatalytic elimination of DCF over CFs@La-BiOIO3/Bi2O3 photocatalyst was proposed. Similar studies can be extended to other structures capable of achieving rational Fermi level modulation and synchronous carrier introduction for the remediation of polluted waters, providing novel perspectives for improving photocatalytic driving capacity.

Successive self-nucleation and Annealing technique applied to polypropylene/butyl rubber composites: Recycling alternatives for vacuum bagging materials

The aerospace sector uses butyl rubber to manufacture carbon fiber components through an autoclave or infusion. Both manufacturing techniques require a high vacuum to achieve adequate impregnation of the carbon fiber fabrics with epoxy resin, and butyl rubber is used as the sealant. The aerospace sector discontinues materials with shelf life expired, and butyl rubber is one of the materials most discontinued for not being used within the designated time. This work presents the development of composites using polypropylene and discontinued butyl tape. Composites with 30, 50, and 70 wt% of butyl rubber content were prepared using a twin-screw extruder. The structural analysis showed that the composites with 50 wt% and 70 wt% are similar to butyl rubber, while the compound with 30 wt% of butyl is similar to polypropylene. The degree of crystallinity of the compound with 50 wt% of butyl content was 18% higher than the PP, and the melting temperature decreased by 30% with the higher butyl content. SSA revealed that the highest enthalpic contribution occurred in the crystalline fraction of higher perfection, except for the compound with 50 wt% of butyl content, whose less perfect crystalline populations grew at the expense of the most perfect crystals. The reduction of the crystalline fraction implies that butyl interferes with the formation of crystals, developing populations with lower lamellar thickness that favors the overall crystallinity of the compound. Young’s modulus, yield strength, and nominal strain decreased with butyl rubber content. The composites showed rough failure surfaces with solid butyl rubber particles and poor adhesion to polypropylene. Butyl particles with diverse sizes and geometries lead to sudden failure of the composites and high dispersion in strain values.

Fabrication of carbon fiber reinforced SiC composites based on laser directed energy deposition

Carbon fiber reinforced silicon carbide ceramic matrix composites (CF/SiC) are widely applied in aerospace and other industries fields for its extraordinary properties. Nevertheless, traditional preparation processes encounter the challenges of long cyclicality, high economic cost due to the increasing requests. Consequently, this work integrates the CF/SiC composites with the novel laser directed energy deposition (L-DED) printing technology, which is differing from conventional 3D printing technology for it omits the post-processing procedure. CF/SiC composites are designed and manufactured efficiently, and the effects of carbon fiber addition are analyzed. Mechanical properties are utilized to characterize the internal bonding strength and the results reveal that the maximum flexural and compressive reach 119.33 ± 4.04 MPa and 396.20 ± 10.21 MPa, respectively, attributed to the enhanced crack propagation resistance caused by the carbon fiber addition. At the same time, this paper not only characterizes the performance through objective experimental data, but also expounds the formation mechanism of pores and cracks through material analysis. In conclusion, this work pioneers the application of L-DED molding technology to CF/SiC composites fabrication and validated its preparation capability, which not only improves the efficiency but also opens up a new path for CF/SiC composites preparation in the field of 3D printing.

Z-scheme Ag2O/ZnO heterostructure on carbon fibers for efficient photocatalysis of tetracycline

Antibiotics can be transferred from water bodies to soil environment through irrigation, and then enriched in agricultural products, causing larger scale pollution. Due to the ability of antibiotics to inhibit microbial activity, the use of traditional microbial methods is not suitable for treating wastewater containing antibiotics. In nowadays, photocatalytic technology has been widely studied to deeply mineralize low concentration water-soluble pollutants like antibiotics. However, the photocatalytic technology still faces two challenges, namely the difficulty of recovering and reusing powdered catalysts, and the insufficient activity of catalysts. In this work, we designed a Z-scheme Ag2O/ZnO heterostructure in situ grown on large scaled carbon fiber (named CF/ZnO/Ag2O) to enhance the efficiency of photocatalysis of tetracycline (TC) in water. The large-area carbon fiber cloth facilitates the recovery and industrial application of the catalyst, while the Z-scheme heterojunction structure significantly enhances the charge separation efficiency and catalytic performance. The results show that the interface formed by the close contact between ZnO and Ag2O provides an effective channel for charge transfer between them. Compared with existing catalysts, the prepared Z-scheme Ag2O/ZnO photocatalyst not only has higher activity, but also could solve the problem of easy loss and difficult recycling of powdered catalysts in water. Importantly, the efficiency for photocatalysis of tetracycline (TC) over CF/ZnO/Ag2O is about 94.50%, and after sixth cycles, the degradation rate is still 81.32%. The catalyst grows in situ on the surface of carbon fibers and is not easily detached. The degradation pathways of TC, toxicity analysis of intermediates and mechanism of the photocatalysis over CF/ZnO/Ag2O were explored. These characteristics make this catalyst have higher practical application potential and value, especially in improving the biodegradability of antibiotic wastewater and achieving deep purification of wastewater to improve effluent quality.

Development of ultra-high temperature ceramic matrix composites for hypersonic applications via reactive melt infiltration and mechanical testing under high temperature

AbstractIn the ongoing development of hypersonic technologies, material advancements play a key role in meeting the ever-increasing thermomechanical demands of these applications. Ultra-High Temperature Ceramic Matrix Composites (UHTCMCs) offer a promising solution for components operating under such extreme conditions. Their outstanding thermomechanical properties, including high temperature and thermal shock resistance, excellent thermal conductivity and mechanical strength, position them as ideal candidates for applications in fields like leading edges or inlet ramps for ramjets and scramjets. Due to their remarkable material composition, UHTCMCs are capable of operating in temperature regimes that surpass 1700 °C during their operation times under oxidizing atmospheres. At the German Aerospace Center (DLR), a UHTCMC material based on carbon fibres and a zirconium diboride matrix is being developed utilizing Reactive Melt Infiltration (RMI). With RMI, the orientation of the reinforcement fibres can be tailored, to enable the material to fulfill the demanding load requirements. The reactive melt infiltration process comprises three stages: preform fabrication, pyrolysis, and the actual melt infiltration. The foundation for important material properties of the final ceramic, including the matrix composition, is established in the preform production, which is a crucial step in the process. A boron- and zirconium diboride-based slurry is infiltrated into pitch-based carbon fibre fabric. Subsequently, the preforms are consolidated, pyrolysed, and infiltrated with molten Zr2Cu to obtain the UHTC matrix by in situ reaction with the preform elements. Scanning Electron Microscopy (SEM) and Energy-dispersive X-Ray Spectroscopy (EDX) enable the examination of the microstructural features, including the arrangement and distribution of zirconium diboride within the matrix. Mechanical evaluation of the UHTCMCs is conducted via 3-point bending tests at both room temperature and at elevated temperature at 900 °C. It has been demonstrated that Ultra-High Temperature Ceramic Matrix Composites can be produced by means of reactive melt infiltration, and that they retain their strength even at elevated temperatures.

Visible light induced photocatalytic degradation of methylene blue using carbon fibre cloth - Bismuth oxybromide – Water hyacinth derived silver nanocomposite

Methylene Blue (MB), a frequently used cationic dye, is recognized for its persistence and probable toxicity, making its removal from wastewater an urgent environmental concern. This study reports the solar photocatalytic degradation efficiency of MB by bismuth oxybromide-green silver nanoparticles (AgNPs) as catalyst. AgNPs were produced by the green synthesis method from an invasive aquatic weed water hyacinth (Pontederia crassipes). The AgNPs were doped on Bismuth oxybromide (BiOBr) nanosheets formed on the surface of carbon fibre cloth (CFC) to form the catalyst CFC-BiOBr-Ag. Under optimum conditions of 5 mg/L of initial MB concentration and near-neutral pH, one piece of CFC-BiOBr-Ag photocatalyst (5.78 mg/L) exhibited 95.68% degradation efficiency of MB in 4 h. TOC removal studies showed a removal efficiency of 74.82% after 4 h, indicating the potential for mineralization of MB. Adsorption-photocatalysis-desorption study revealed complete degradation of adsorbed MB at the end of the photocatalytic degradation. Additionally, the catalyst exhibited good reusability, with more than 84.88% degradation efficiency even after five cycles of use. Under direct sunlight, the CFC-BiOBr-Ag catalyst demonstrated MB degradation efficiency of 97.52% after 3 h of treatment. MB breakdown was evidently done by the hole (h+) and the superoxide radical (O2•−). The mechanism of MB degradation was adsorption and subsequent degradation by the CFC-BiOBr-Ag photocatalyst. The prevalent degradation reactions such as demethylation, ring opening, hydroxylation, •OH radicle attack, desulfonication, hydrolysis etc. led to formation of various intermediates which further mineralized to CO2 and H2O.

Carbon fiber fabrics functionalized with monoclinic CuO nanostructures using seed-assisted hydrothermal growth treatment

The woven carbon fibers (WCF) fabrics were functionalized by growing copper-oxide (CuO) nanostructures using Seed-assisted hydrothermal technique. The effective growth of CuO on surface hydrolyzed WCF samples were achieved by seeding followed by growth treatment in the prepared precursor solution. The impact of hydrothermal process parameters such as number of seeding cycles, duration of growth treatment and molar concentration of growth solution were studied by performing 96 set of experiments with three repetitions. In this work detailed analysis of structural, morphological, and elemental attributes of the CuO-coated WCF fabrics samples have been done. The WCF fabrics were uniformly coated with monoclinic CuO nanostructures having nanopellets, nanoflakes, nanowires, and nanoflowers morphologies. Different characterization techniques such as field emission scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, FT-IR spectroscopy and thermo-gravimetric analyzer were used to study different attributes of CuO-modified WCF samples. The number of seeding treatments and the length of growth treatment had a significant impact on growth of CuO nanostructures on WCF. The detailed analysis exhibits that the developed CuO-modified WCF samples may enhance interfacial surface area, bonding capacity and reduce void content by allowing nanostructures to cross-link together and with polymer matrix while fabricating composite materials.

Effect of Carbon Fiber Fabric Modification on the Tensile Mechanical Characteristics of Polyether Ether Ketone/Carbon Fiber Fabric Composites

In the aviation industry lightweight, high-strength materials have replaced metals to lighten vehicles and reduce fuel consumption. Polymer matrix composite materials have thus been chosen because they are highly resistant to oxidation and chemicals, are lightweight compared to metals, and are simple to manufacture. The aim of this study was to increase the compatibility of carbon fiber fabric (CFF) with polyether ether ketone (PEEK) polymer. Meldrum’s acid and nitric acid modified CFFs were assessed using energy dispersive X-ray spectrometry (EDX), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The PEEK matrix composites reinforced with CFF were produced by a compression molding method. The composites were characterized by tensile strength tests, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). We concluded that the CFF modification improved the compatibility between CFF and PEEK. The enhancement of the tensile properties of the composites was another indication of this modification’s beneficial effects.

Facile metal-oriented in-situ growth of zeolitic imidazole framework membranes on carbon fiber cloth with superior capacitive performance

Facile metal-oriented in-situ growth of zeolitic imidazole framework membranes on carbon fiber cloth with superior capacitive performance

Electrocatalytically active and charged natural chalcopyrite for nitrate-contaminated wastewater purification extended to energy storage Zn-NO3− battery

Charged natural chalcopyrite (CuFeS2, Ncpy) was developed for a three-dimensional electrochemical nitrate reduction (3D ENO3−RR) system with carbon fiber cloth cathode and Ti/IrO2 anode and Zn-NO3− battery. The 3D ENO3−RR system with Ncpy particle electrodes (PEs) possessed superior nitrate removal of 95.6 % and N2 selectivity of 76 % with excellent reusability under a broad pH range of 2–13 involving heterogeneous and homogeneous radical mechanisms. The Zn-NO3− battery with Ncpy cathode delivered an open-circuit voltage of 1.03 V and a cycling stability over 210 h. It was found that Ncpy PEs functioned through self-oxidation, surface dynamic reconstruction (Cu1.02Fe1.0S1.72O1.66 to Cu0.61Fe1.0S0.27O2.98), intrinsic micro-electric field (CuI, S2− anodic and FeIII cathodic poles), and reactive species (•OH, SO4•−, 1O2, •O2− and •H) generation. Computational analyses reveal that CuFeS2(112) surface with the lowest surface energy preferentially exposes Fe and Cu atoms. Cu site is beneficial for reducing NO3− to NO2−, Fe and Fe−Cu dual sites are conducive to N2 selectivity, lowering the overall reaction barriers. It paves the way for selective NO3− reduction in wastewater treatment and can be further extended to energy storage devices by utilizing low-cost Ncpy.

Multifunctional performances of structural battery composite full-cells based on carbon fiber anode and LiFePO4 loaded carbon fiber cathode

In this work, the structural battery composite (SBC) full-cells based on carbon fiber (CFs) were fabricated using a three-step hot pressing method. LiFePO4 (LFP) was loaded onto CF fabrics considering the influences of hot pressing parameters including the pressure and the temperature. The SBC full-cells were subsequently fabricated using the LFP loaded CF cathode, the CF anode, the glass fiber (GF) separator via a structural electrolyte (SE) filming process, followed by the second hot pressing. The multifunctional efficiencies were assessed for SBCs with SE containing different components. To reduce the capacity loss, the SBC was eventually encapsulated with the GF/Vinyl Ester prepreg and thermally cured in the third hot pressing. The capacity retention of the SBC was significantly improved after encapsulation. This work could be seen as a further step forward the engineering fabrication of the SBC full-cells based on both CF anodes and cathodes.

Multifunctional hierarchical electronic skins: Unveiling self-repairing mechanisms and advancements in sensing and shielding performance

In light of advancements in electronic skins (E-skins), their application in extreme environments poses significant challenges. Inspired by real human skin, we have developed a hierarchical structured electronic skin that utilizes flexible carbon fiber fabric as a framework. Copper nanoflakes and embedded sensors function as the neural layer, while Ethylene Vinyl Acetate acts as the dermal layer, and Polytetrafluoroethylene is employed as the epidermal layer. The reported E-skin demonstrates outstanding flexibility, excellent heat resistance, robust mechanical properties (fracture strength of 1600 MPa, Young's modulus approximately 3.8 GPa), exceptional bending/compression strain performance, excellent hydrophobicity (water contact angle of 120°), effective electromagnetic shielding performance (approximately 45 dB total shielding effectiveness for X-band), and electromagnetic wave absorption capability. Additionally, this E-skin possesses self-healing properties, capable of restoring to its original hydrophobic state within 30 s under a 9V voltage through the Joule heating effect, complemented by corresponding theoretical and mathematical modeling. This E-skin introduces a novel, environmentally friendly, and operationally simple strategy for enhancing the extreme environment resistance and durability of flexible devices.

Engineering of Reversibly Cross-Linked Elastomers Toward Flexible and Recyclable Elastomer/Carbon Fiber Composites with Extraordinary Tearing Resistance.

Carbon fiber (CF)-reinforced polymers (CFRPs) demonstrate potential for use in personal protective equipment. However, existing CFRPs are typically rigid, nonrecyclable, and lack of tearing resistance. In this study, flexible, recyclable, and tearing resistant polyurethane (PU)-CF composites are fabricated through complexation of reversibly cross-linked PU elastomer binders with CF fabrics. The PU-CF composites possess a high strength of 767MPa and a record-high fracture energy of 2012kJ m-2. The high performance of the PU-CF composites originates from the well-engineered PU elastomer binders that are obtained by cross-linking polytetrahydrofuran chains with in situ-formed nanodomains composed of hierarchical supramolecular interactions of hydrogen and coordination bonds. When subjected to tearing, the force concentrated on the damaged regions of the PU-CF composites can be effectively distributed to a wider area through the PU binders, leading to a significantly enhanced tearing resistance of the composites. The strong interfacial adhesion between PU binders and the CF fabrics enables the fracture of the CF in bundles, thereby significantly enhancing the strength and fracture energy of the composites. Because of the dynamic nature of the PU elastomer binders, the PU-CF composites can be recycled through the dissociation of the PU elastomer binders.

Rational construction of noble-metal-free fuel cell-supercapacitor hybrid power source using polyaniline electrode as both anode and cathode

The integration of fuel cell device and supercapacitor device into a singular hybrid power source at the electrode level can make the best use of the advantages of each individual device and more importantly, eliminate the energy loss by virtue of the conversion of chemical energy to electric energy on electrocatalyst material and the storage of electric energy on energy storage material simultaneously. To avoid the use of noble metal electrocatalyst and exploit the dual electrocatalytic and capacitive function of polyaniline, a noble-metal-free fuel cell-supercapacitor hybrid power source employing polyaniline electrode as both anode and cathode is rationally constructed. Based on electrochemical in-situ Raman spectroscopy, this work proposes that the open circuit potential (OCP) of polyaniline electrode is a simple and quick indicator of the redox state of polyaniline. After carefully selecting the fuel and carbon-based support, it is found that the ascorbic acid fuel and the carbon fiber cloth supported polyaniline contributes to the lowest OCP threshold in the anode, and thus the fastest self-charge and largest stabilized open circuit voltage of hybrid power source. The hybrid power source can be self-charged to 0.32 V and yield a peak power density of 0.21 mW cm−2.