Interlayer Material Research Articles

Cold Bent Laminated Glass Application – Numerical Research

AbstractIn curvilinear and free‐form glass facade constructions, more and more cold bent laminated glass is applied. The high optical quality of cold bent glass allows for continuously smooth curved and high transparent facades. Moreover, a high performance and economical design is achieved using spatial load‐bearing behaviour. The bending in such curved glass facades is obtained by mechanical fixings upon a curved substructure at the installation on site or by lamination bending with stiff interlayers. These techniques shape the glazing but induce permanent bending stresses as well as shear stresses in the laminated glass, which significantly depend on the interlayer's material behaviour as a function of time and temperature. For the application of cold bent laminated glass in facades numerous factors must be considered ‐ achievable bending radii, glazing dimensions and geometry, load‐bearing capacities, bending forces as well as required supports. These aspects are significantly influenced by the material stiffness of the interlayer type and the glass structure. For this reason, the curved bending process with mechanical line fixings was numerically investigated. The focus lays on the influence of the stiffness of the polymer interlayer and the corresponding suitability for uniaxial cold bent laminated glass applications in different geometries. In the present paper, technical design information is introduced based on numerical simulations to assist designers in understanding the principles of uniaxial cold bent laminated glass with different glazing parameters. In conclusion, constructive recommendations for application in curvilinear glass facades are given.

Mechanical Behavior of Laminated Glass Polymer Interlayer Subjected to Environmental Effects

It is known that weathering action has a significant impact on polymer interlayer materials, and previous studies have evaluated certain aspects of weathering such as temperature, humidity, and UV radiation. In this paper, the environmental effect on the mechanical properties of the virgin and cured/processed polymer interlayer materials will be studied. Three polymer interlayer materials were focused, i.e., Polyvinyl butyral (PVB), Ethylene-vinyl acetate (EVA), and Ionomer (SG), due to their industrial interest. Testing setups were designed to apply the environmental effects and perform mechanical testing on the polymeric materials. Four environmental effects were studied, including water submersion (E1), constant high temperature (E2), cyclic temperature with low relative humidity (E3), cyclic temperature, and relative humidity (E4). After the exposure of these materials to these environmental effects, the samples were prepared and mechanically tested. Uniaxial tests were performed under static and high strain rates (around 45-1). It was found that under dynamic load, the properties of EVA such as the strength, maximum strain, and the toughness were not significantly affected by the environmental effects. SG5000 properties were significantly affected.

One-step synthesis of low-cost perylenediimide-based cathode interfacial materials for efficient inverted perovskite solar cells

Interface engineering plays an important role in improving the performance of perovskite devices. Herein, we reported two perylenediimide small molecular cathode interface materials (CIMs), PDI-2N and PDI-4N, synthesized by a simple method and with good alcohol soluble, which could be used as cathode interfacial layer (CIL) for high-performance inverted perovskite solar cells (PVSCs). The PDI-4N exhibits larger electrical conductivity, electron mobility and self-doping properties than PDI-2N because of more dimethylamino functional groups in the amide positions. Based on these superiorities, a peak PCE of 21.33% with PDI-4N as CIL was achieved, which is the highest PCE for PDI-based interlayer materials as the cathode interlayer in inverted PVSCs. While the PCE with PDI-2N as CIL is only 17.41%. The significant improvement in device efficiency for PDI-4N based device is due to reduced defect density, lower dark current, larger recombination resistance and better surface morphology, which improved charge transport and collection at the PC61BM/Ag interface. Moreover, the ambient stabilities of PVSCs with PDI-2N and PDI-4N as CIL show that the CILs can effectively improve the device stability, and good stability with a PCE loss of only ∼3.0% after 600 h is also obtained. In a word, this work will provide us with molecular design approach by one-step to develop novel cathode interface materials with functional side chains for high-efficiency PVSCs.

Atomistic Investigation of Titanium Carbide Ti8C5 under Impact Loading

Titanium carbides attract attention from both academic and industry fields because of their intriguing mechanical properties and proven potential as appealing candidates in the variety of fields such as nanomechanics, nanoelectronics, energy storage and oil/water separation devices. A recent study revealed that the presence of Ti8C5 not only improves the impact strength of composites as coatings, but also possesses significant strengthening performance as an interlayer material in composites by forming strong bonding between different matrices, which sheds light on the design of impact protection composite materials. To further investigate the impact resistance and strengthening mechanism of Ti8C5, a pilot Molecular Dynamics (MD) study utilizing comb3 potential is carried out on a Ti8C5 nanosheet by subjecting it to hypervelocity impacts. The deformation behaviour of Ti8C5 and the related impact resist mechanisms are assessed in this research. At a low impact velocity ~0.5 km/s, the main resonance frequency of Ti8C5 is 11.9 GHz and its low Q factor (111.9) indicates a decent energy damping capability, which would eliminate the received energy in an interfacial reflection process and weaken the shock waves for Ti8C5 strengthened composites. As the impact velocity increases above the threshold of 1.8 km/s, Ti8C5 demonstrates brittle behaviour, which is signified by its insignificant out-of-plane deformation prior to crack initiation. When tracking atomic Von Mises stress distribution, the elastic wave propagation velocity of Ti8C5 is calculated to be 5.34 and 5.90 km/s for X and Y directions, respectively. These figures are inferior compared with graphene and copper, which indicate slower energy delocalization rates and thus less energy dissipation via deformation is expected prior to bond break. However, because of its relatively small mass density comparing with copper, Ti8C5 presents superior specific penetration. This study provides a fundamental understanding of the deformation and penetration mechanisms of titanium carbide nanosheets under impact, which is crucial in order to facilitate emerging impact protection applications for titanium carbide-related composites.

Collectable adsorbent based on the adsorption characteristics of sodium citrate-pretreated vermiculite for cesium ion in an aquatic environment

This study aimed to develop a collectable adsorbent for Cs using clay mineral and alginate gel. The adsorption capacity of vermiculite (Verm) for Cs increased from 97.1 mg/g to 119 mg/g after sodium citric treatment. The Verm used in this study has a partial chlorite structure, and the existence of interlayer material was considered. The adsorption sites of Verm for Cs increased because the interlayer material in the partly chlorite structure was removed via sodium citric treatment. The Langmuir adsorption isotherm described this adsorption phenomenon well, indicating that the adsorption of Cs by Verm after sodium citric treatment (Verm-Cit) is monolayer adsorption. Since a typical phenomenon was also observed in which the basal spacing became approximately 1.0 nm when Cs was adsorbed by the interlayer of vermiculite, the interlayer of Verm-Cit functioned as an adsorption site. Verm-Cit was encapsulated in alginate gel beads (AG-Verm-Cit) for accessible collection after adsorption. Although the equilibrium adsorption time of AG-Verm-Cit was extended from 10 min without encapsulation (Verm-Cit) to over 360 min, an adsorption capacity of 60.5 mg/g was obtained even after 30 min. The developed adsorbent requires time to reach equilibrium; however, the adsorption capacity was similar to or higher than reported in previous studies, even with a relatively shorter contact time. Additionally, the weight and volume of the adsorbent encapsulated in alginate gel beads can be decreased by air drying without heat. These properties can contribute to removing Cs from the aquatic environment and to the stable management of adsorbents with radionuclides.

Laser Joining of CFRTS and Steel by Interfacial Pressure Control

The carbon fiber-reinforced polymer (CFRP) metal structure is widely used in various industries to reduce the weight and cost of the structure without compromising performance. The main challenge for manufacturing the CFRP metal structure comes from the lack of flexible and robust joining processes. In this study, a new laser joining process was developed that used a thin layer of polyamide 6 as an interlayer material lying between carbon fiber-reinforced thermosets and a quenching-partition (QP) 980 steel to achieve the joint since the laser can’t directly join the steel to the thermoset composite. It was found that the joint’s strength was seriously degraded by the porosity’s formation. The porosity formation mechanism was studied by online-recording the thermal history inside the joint during the laser joining process. Experimental results demonstrated that the emerging of the porosities in the joint was mainly caused by the cooling shrinkage instead of pyrolysis gas release. Furthermore, a new approach of controlling and optimizing the interfacial pressure was developed to suppress the porosity formation in the joint, which can significantly reduce the porosity rate from 25.8 to 1.2% and dramatically improve the joint shear strength from 10.69 to 18.6 MPa by 73.99%.

Centrifugal Model Test and Simulation of Geogrid Reinforced Backfill and EPS Interlayer on Bridge Abutment

In this paper, the use of geotechnical centrifuge and numerical modeling techniques to investigate the influence of geogrid reinforcement and EPS interlayer on the lateral earth pressure and the backfill surface settlements behind gravity abutment and pile-supported abutment is reported. According to the principle of equal strain, the abutment back structure, foundation, backfill material, grid and interlayer material were simulated, and the centrifugal model test for two types of abutments was carried out with a model scale of n = 62.5, 40, respectively. The tests showed that the reinforcement of the geogrid could reduce the surface settlement of backfill and the lateral earth pressure of the backfill on the back of abutment. After setting the EPS interlayer, the influence of abutment displacement on earth pressure could be eliminated, and the earth pressure of the backfill material on the abutment back was significantly reduced. The “interlayer + geogrid” structure further reduced the earth pressure of backfill material on the abutment back. The existence of the EPS interlayer adjusted the strain distribution of the reinforced material, significantly increasing the strain of the reinforced material near the abutment, which was conducive to the reinforcement effect. The above research conclusions could provide a basis for the design and practical application of abutment backfill materials.

Dynamics of Internal Electric Field Screening in Hybrid Perovskite Solar Cells Probed Using Electroabsorption

Electric fields arising from the distribution of charge in metal-halide perovskite solar cells are critical for understanding the many weird and wonderful optoelectronic properties displayed by these devices. Mobile ionic defects are thought to accumulate at interfaces to screen electric fields within the bulk of the perovskite semiconductor on application of external bias, but tools are needed to directly probe the dynamics of this process. Here, we show that electroabsorption measurements allow the electric field within the active layer to be tracked as a function of frequency or time. The magnitude of the electroabsorption signal, corresponding to the strength of the electric field in the perovskite layer, falls off for externally applied low-frequency voltages or at long times following voltage steps. Our observations are consistent with drift-diffusion simulations, impedance spectroscopy, and transient photocurrent measurements. They indicate charge redistribution on timescales ranging from 10 ms to 100 s, depending on the device interlayer material, perovskite composition, dominant charged defect, and illumination conditions. The method can be used on typical solar-cell structures and has the potential to become a routine characterization tool for optimizing hybrid perovskite devices.

Synchronous Doping Effects of Cathode Interlayers on Efficient Organic Solar Cells

An in-depth understanding of the role of cathode interlayers in nonfullerene organic solar cells (OSCs) is challenging due to ambiguous and complicated interfacial doping, which complicates molecular designs and hinders progress in optoelectronic performance. Herein, we describe synchronous doping effects (a combination of the cathode interlayer’s self-doping and its doping on acceptors in the active layer) of cathode interlayers. The electronic nature of π-conjugated cores in cathode interlayer materials has a negligible influence on nonfullerene acceptor doping but an obvious influence on their self-doping. A synchronous doping effect generated by the amine-substituted fullerene (C60-N), with its electron-withdrawing C60 core, facilitates interfacial charge transport and collection, affording a remarkable power conversion efficiency > 18% for PM6:L8-BO based OSCs, which is among the highest reported values for binary OSCs. This discovery of synchronous doping on interfacial modification provides new and useful molecular design guidelines for high-performance cathode modifiers in organic electronics.

On the interlayer toughening of carbon fibre/epoxy composites using surface-activated ultra-thin PEEK films

The exceptional mechanical properties of Polyether-ether-ketone(PEEK) polymers make them ideal candidates for interlayer toughening of carbon fibre/epoxy composites. Herein, ultra-thin PEEK films with a thickness of 8μm, 18μm and 25μm were used for interlayer toughening of an aerospace-grade carbon fibre/epoxy composite. The mode-I and mode-II fracture behaviour of the interleaved laminates were investigated, with the fracture mechanisms being investigated. The surfaces of the PEEK films were treated by a UV-irradiation technique to enhance their intrinsically low surface activities. This significantly increased the adhesion at the interface between the PEEK interlayers and the composite matrix. A topography analysis on the fracture surfaces revealed extensive damage of the PEEK interlayers during the fracture process of the laminates. Owing to the exceptional properties of the PEEK films, significant enhancements in the mode-I and mode-II fracture properties of the laminates were obtained, i.e. the mode-I and mode-II fracture energies were significantly increased by 227% and 441%, respectively. Overall, the UV-treated PEEK films proved superior effectivenesses for laminate toughening when compared to the other state-of-the-art interlayer materials.

Microstructural Evolution Revealed By Operando X-Ray Tomographic Microscopy in Next Generation Batteries

Sulfur conversion chemistry boasts a high theoretical specific capacity of 1672 mAh/gs and promises to deliver a high-energy density battery when combined with a lithium metal anode (3862 mAh/gLi). The use of such chemistries has the additional benefits of utilizing abundant and low cost materials in the cathode, i.e. carbon and sulfur.[1] Despite clear advantages, lithium-sulfur (Li-S) batteries still face a low practical energy density, poor rate performance, and limited cycling life. These issues are a result of the complex conversion chemistry of the cathode, and the stripping/plating mechanism of the Li-metal anode. These processes include the dissolution and diffusion of polysulfide species through the cell’s electrolyte from the cathode resulting in capacity fade, in addition to the growth of dendritic structures from the anode causing the formation of ‘dead lithium’ and short circuiting of the battery. A plethora of strategies have been developed to address the issues posed by the soluble polysulfide species, from using additives to prevent polysulfide shuttling, to encapsulation of sulfur to prevent its dissolution. While to address the growth of Li-dendrites, electrolyte formulations and the use of interlayer materials have been investigated.When developing these strategies, a detailed understanding of the conversion chemistry and Li-metal plating/stripping mechanisms during cycling is required. This can be obtained by e.g. the use of Raman spectroscopy to probe chemical changes to electrolytes and observe polysulfide speciation,[2] or using phase-field modelling to investigate factors that influence the growth mechanisms of Li-metal during plating.[3] In addition, sulfur dissolution and Li-metal dendrite growth induce microstructural changes that need to be probed using techniques with an appropriate resolution and field-of-view, e.g. synchrotron x-ray tomographic microscopy (XTM), which is capable of micrometre resolution, a near millimetre wide field of view, and measurement times of less than 60 seconds. This allows synchrotron XTM to continuously probe microstructural changes during battery operation, giving quantitative insights into the complex electrochemical mechanisms of the sulfur cathode and Li-metal anode.In this contribution we address the conversion processes of sulfur and its relation in limiting the battery’s practical specific capacity by using a capillary cell type battery, placing the entire cathode within the field of view of the XTM measurement. This enables quantification of the sulfur phase and correlative analysis with simultaneously acquired electrochemical data.[4] We demonstrate the full dissolution of elemental sulfur, with further conversion of sulfur species occurring immediately, and that an efficient diffusion of dissolved polysulfide species through and from the cathode is crucial to achieve a high specific capacity of Li-S cells in practice. Furthermore, we find that in the final step of cell discharge, a uniform and porous Li2S layer is formed on the cathode surface, effectively limiting access to the carbon surface and preventing further polysulfide conversion. We also demonstrate XTM as a unique technique to follow the growth of Li-metal microstructures in real time showing the difference in growth mechanisms when using different electrolyte compositions and under different cycling conditions. We observed change in the growth mechanisms of Li-metal. from homogenous mossy growth of Li-metal, to island dendritic growth and the formation of dead Li, to the growth of a globular phase, showing a changes in the fundamental process of Li-metal growth.[1] M. Agostini, J.Y. Hwang, H.M. Kim, P. Bruni, S. Brutti, F. Croce, A. Matic, Y.K. Sun, Adv. Energy Mater. 8 (2018) 1–7.[2] M. Sadd, M. Agostini, S. Xiong, A. Matic, ChemPhysChem 23 (2022).[3] Y. Liu, X. Xu, M. Sadd, O.O. Kapitanova, V.A. Krivchenko, J. Ban, J. Wang, X. Jiao, Z. Song, J. Song, S. Xiong, A. Matic, Adv. Sci. 2003301 (2021) 1–11.[4] M. Sadd, S. De Angelis, S. Colding‐Jørgensen, D. Blanchard, R.E. Johnsen, S. Sanna, E. Borisova, A. Matic, J.R. Bowen, Adv. Energy Mater. 2103126 (2022) 2103126.

Anode interfacial modification for non‐fullerene polymer solar cells: Recent advances and prospects

AbstractRecently, the power conversion efficiency (PCE) of single‐junction non‐fullerene polymer solar cells (NF‐PSCs) has surpassed 19% due to the fast development of novel donor polymers, NF‐acceptors, device engineering, and interlayer materials. The anode interlayer (AIL) plays a vital role in improving the efficiency and stability of PSCs. The challenges and opportunities in this research area encourage researchers to pursue great innovation in developing new materials and strategies for highly efficient NF‐PSCs. This review summarizes the recent development of AIL materials and their modification strategies in single‐junction NF‐PSCs. Firstly, a brief introduction, key functions, basic requirements, and peculiar features of AILs when employed in NF‐PSCs are discussed. Then, the impact of AIL materials (including organic, inorganic, and hybrid materials) on the PCE and the stability of NF‐PSCs are described. Afterward, the fabrication of large‐area devices and related issues are highlighted. The summary and the future challenges regarding efficient AIL are summarized in the last section of this review.image

Acetylene black interlayer regulated sulfur deposition for lithium-sulfur batteries with high utilization and long-term life

Lithium-sulfur (Li-S) batteries are considered to be competitive next-generation energy storage systems. However, practical applications are limited due to the shuttle of lithium polysulfides (LiPSs) and the poor electronic conductivity of the sulfur cathode, especially at high-rate currents. Here, we applied commercialized Acetylene black (AB) as separator coating in Li-S batteries. The stacking of AB nanospheres forms a void space that can physically adsorb polysulfides, store electrolytes, and promote lithium-ion diffusion; Simultaneously, it forms an excellent electronic conduction network that significantly improves the utilization of higher-order LiPSs. The thickness and composition of the coating can regulate the nucleation of crystalline S and Li2S to promote the uniform deposition of solid-phase particles. AB-150 releases an initial capacity of 961.3 mAh g−1 and still maintains at 825 mAh g−1 after 100 cycles with a capacity retention rate of 85.8% at 0.2C. Even remains at 371.2 mAh g−1 after 1000 cycles at 1C with a weak capacity decay rate of 0.06% per cycle. These understandings can also be extended to the design of polar/catalytic interlayer materials driving the large-scale application of Li-S batteries.

IN BETWEEN: An Interlayer Material Study for Interlocking Cast Glass Blocks

Interlocking cast glass assemblies are a promising solution for architectural cast-glass applications aiming for high transparency and a reversible structure that allows the reuse of the glass components (Oikonomopoulou et al.,2018; Oikonomopoulou,2019b). In such a system, an interlayer material between the glass elements is essential, to assist the homogenous stress distribution and account for the surface microasperities of the glass elements. Towards circularity, this material should be dry (and not an adhesive), allowing for the eventual disassembly of the system. Previous experimental work by (Aurik at al.,2018; Oikonomopoulou at al.,2019b) has focused on the use of PU and PVC interlayers as suitable candidates; the focus in those studies has been solely placed on the mechanical performance of the interlayer material. This research provides a review of potential material candidates suitable for interlayers of an interlocking cast glass assembly based on a set of revised design and performance criteria that are divided into primary and secondary. Furthermore, the impact their unique material properties have on the potential application of the interlocking system is examined. The whole process, from fabrication to construction of the entire assembly, based on an assumed building scenario, is presented in a chain reaction manner, whose starting point is the interlayer itself. After defining the design criteria the interlayer should adhere to, the proposed candidates are: PETG sheets (Vivak®), Neoprene, Aluminum, Laminated Polyurethane (PU) and a Soft-core aluminum interlayer. The unique properties and fabrication challenges of all five proposed interlayers are considered, as well as their properties in relation to assembly, which leads to the development of two distinct assembly sequences. The main distinction concerns the interlayers that risk creeping and those that do not. The research concludes with a comparison between the interlocking assembly and the other glass block assemblies currently applied.

Polyamide membranes with a ZIF-8@Tannic acid core-shell nanoparticles interlayer to enhance nanofiltration performance

Polyamide nanofiltration membranes with an interlayer of either a plant polyphenol tannic acid (TA) coating to improve polyamide formation or zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) as a sacrificial template have been recently attracting great interest, although none has reported such a dual-functional interlayer. In this study, we demonstrated a facile and controllable one-pot synthesis of novel ZIF-8@TA core-shell NPs. Mixing Zn2+, Hmim, and TA in an aqueous solution could readily give rise to these NPs. Microscopy characterizations showed that composition and morphology of NPs could be easily controlled by the amount of TA used. Comparing with the thin film nanocomposite (TFN) membrane prepared with ZIF-8 NPs as an interlayer, which had significant defects in its polyamide layer due to the aggregation of hydrophobic ZIF-8 NPs, the homogeneous and hydrophilic ZIF-8@TA NPs interlayered TFN membranes demonstrated intact polyamide layers. It was found that when 0.5 mg ZIF-8@TA1.0 NPs were used, the obtained TFN membrane showed a high water permeance of 20.7 L m−2 h−1 bar−1 and Na2SO4 rejection of 96.6 %, typically outperforming other interlayer-based PA membranes reported elsewhere. This work provided not only a novel interlayer material but also deep insights into design of high-performance polyamide membranes.

Effect of process parameters on performances of TWIP steel/Al alloy dissimilar metals butt joints by laser offset welding

In this paper, butt joints of twinning-induced plasticity (TWIP) steel and aluminum alloy dissimilar metals were carried out by the laser offset welding method, and the amount of the aluminum alloy that melted was controlled by adjusting the offset distance of the laser beam spot. The aim of this study was to regulate the influence of the intermetallic compounds (IMCs) layer thickness, crystal structure and crack defects on the tensile strength of the welded joint. The tensile strength of the welded joint was obviously improved by adjusting the welding process parameters without adding any alloying elements. The results demonstrated that the crack initiated at the junction between the aluminum base metal and the weld seam and propagated along with the interface. The increase in the recrystallized fraction was beneficial to improve the tensile strength of the joint. The tensile strength of welded joints with more low-angle grain boundaries was lower. The smaller the thickness of the IMCs layer was, the higher the welded joint strength was. The optimized welding process parameters were as follows: d = 0.2 mm, P = 900 W, V = 15 mm/s and △f = −2 mm in the present study, and the tensile strength of the joint reached 155 MPa. This study provides a theoretical basis for solving the welding cracking problem of steel/aluminum heterojunctions without additional interlayer material and so as to improve the strength of the steel/aluminum laser welded joint.

Influence of Interlayer Materials on the Mechanical Properties and Thermal Stability of a CrAlN Coating on a Tungsten Carbide Substrate

CrAlN coatings have earned significant attention for use in cutting tool coating applications due to their excellent properties such as high hardness and superb oxidation resistance. It is well known that the interlayer between the coating and the substrate can influence the mechanical properties of the coatings. In this work, three interlayers—CrN, CrZrN, and CrN/CrZrSiN—were synthesized between a CrAlN coating and a tungsten carbide substrate to improve the mechanical properties and thermal stability of the CrAlN coating. All the CrAlN coatings with their respective interlayers showed high hardness values in the range of 34.5 to 35.1 GPa, and they were not significantly affected by the interlayer type. However, wear and scratch tests showed that the CrAlN coatings with CrN and CrN/CrZrSiN interlayers exhibited an improved friction coefficient of 0.33 and adhesion strength (Lc2) of 69 N compared to the CrAlN coating with the CrZrN interlayer. These improved wear properties were attributed to the H/E ratio of the interlayer between the coating and the substrate, in that the CrN and CrZrSiN interlayers effectively induced a smooth transition of the coating stress under a loading condition. During the thermal stability tests, the hardness of the CrAlN coating with the CrN/CrZrSiN interlayer was maintained up to 1000 °C due to the excellent oxidation resistance of the CrZrSiN layer, which contained an amorphous SixNy phase.

Effect of electrospun PPENK nanofiber loaded with ZnO nanowires on the mode Ⅱ fracture toughness, flexural properties and ILSS of CF/poly(phthalazinone ether ketone) composites

The weakness of easy delamination for the laminated composites always limits their wide application. In this work, the poly(phthalazinone ether nitrile ketone) (PPENK) multi-scale nanofibrous veils loaded with ZnO nanowires (ZnO@PPENK) were prepared and incorporated into the interlayer of carbon fiber reinforced poly(phthalazinone ether ketone) (PPEK) laminates (CF/PPEK). The structures and morphologies of ZnO@PPENK veils, the mode II interlaminar fracture toughness, and in-plane properties of ZnO@PPENK/CF/PPEK laminates were characterized. The results show that due to the introduction of PPENK interleaving veil, the mode Ⅱ interlayer fracture toughness of the laminated composite increased from 1238 J/m2 to 1769 J/m2 (an increase of 43%), and after loading ZnO nanowires, it further increased to 2618 J/m2, an increase of 112% compared with CF/PPEK. Moreover, the flexural modulus of ZnO@PPENK/CF/PPEK composite was slightly increased by about 10%(115 GPa), and the interlayer shear strength was improved to 78 MPa, about 31% higher than that of CF/PPEK. These results provide a new idea for interlayer materials used for interlayer reinforcement of carbon fiber reinforced polymer composites.

Two-dimensional montmorillonite-based heterostructure for high-rate and long-life lithium-sulfur batteries

In lithium-sulfur batteries, the polysulfide redox reaction kinetics is obstructed by unfavorable electron conduction and ion transportation. To address this issue, a two-dimensional (2D) heterostructure with fast ion/electron transport bi-pathways is designed herein by well integrating monolayer lithium-montmorillonite (MMT) and nitrogen-doped reduced graphene oxide (RGO). The low diffusion barrier on the Li-MMT contributes to the fast lithium ion transport, and the nearby RGO builds high electron conduction network, which enables high-efficiency adsorption-diffusion-conversion for polysulfides and achieves fast electrochemical reaction kinetics. Consequently, the lithium-sulfur batteries using the heterostructure interlayer show effective suppression towards the notorious “shuttle effect” of polysulfides, as well as deliver high initial specific capacity of 1317 mAh g−1 at 0.2 C, high rate capability of 848 mAh g−1 even at 3 C, and low capacity decay rate of 0.011% per cycle at 1 C over 200 cycles and 0.067% per cycle at 2 C over 600 cycles. The corresponding pouch cell shows high initial discharge capacity of 1542 mAh g−1 at 0.05 C. This work exhibits the potential application of the low-cost and environmentally-friendly clay as the 2D heterostructure interlayer material for realizing high-energy-density, long-lasting, and high-rate Li-S batteries.

Highly Efficient Organic Solar Cells Enabled by the Incorporation of a Sulfonated Graphene Doped PEDOT:PSS Interlayer.

An interface modification layer plays an important role in improving the performance of organic solar cells (OSCs). The structure design or doping of electrode interlayer materials can effectively inhibit interfacial carrier recombination and improve ohmic contact between the active layer and the electrodes, which is desirable for realizing high power conversion efficiencies (PCEs). Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been extensively used as a hole-transport layer (HTL) in OSCs. Here, a modification of PEDOT:PSS is proposed using sulfonated graphene (SG) as a secondary dopant for improving the surface morphology and conductivity. The incorporation of the SG-doped PEDOT:PSS as the HTLs in OSCs leads to the increased charge extraction and shows the best PCEs of 17.48% for PM6:Y6 devices and 18.56% for PM6:L8-BO devices. The significant improvement in device performance suggests that SG-PEDOT:PSS is a promising interfacial layer for efficient charge transport and extraction toward high-efficiency OSCs.