Composite Interface Research Articles

Zn interlayer-induced modifications in interfacial structure and fracture behavior of Cyclic Hot-Pressed Mg/Al laminated composites

In this study, a new type of cyclic hot pressing technology was used to prepare magnesium-aluminum composites. In order to further simplify the process, the active zinc interlayer was introduced, and the interfacial bonding strength of Mg/Al LMCs was increased by 43.25%. The traditional Mg/Al LMCs interface is mainly composed of Mg-Al IMCs (β-Mg2Al3 and γ-Mg17Al12), in which the highly regular HCP-β phase leads to brittle fracture of the material. After adding zinc layer, the interface of the composites mainly presents Al-SS, η (MgZn2) and Mg-SS phases. During the preparation process, the solid solution treatment and aging treatment occurred at the composite interface, and a chain GPII zone was formed at the interface between Al-SS and η phase. This region is mainly composed of structurally unstable η′(Al-Mg-Zn), resulting in the GP II band becoming a region rich in lattice defects and a fracture source of the composite.

Controllably constructing organic-inorganic multilevel network structures by regulating the ratio of APES/OCNTs on the basalt fiber surface to enhance the interfacial properties of fiber/polyethersulfone composites

Basalt fiber-reinforced polyethersulfone (BF/PES) composites exhibit high strength, heat resistance, chemical resistance, excellent mechanical properties, and environmental sustainability. However, the smooth and chemically inert surface of BF results in weak interfacial bonding with PES, limiting its broader applications. In this study, an organic-inorganic multilevel network structure was constructed on the fiber surface by optimizing the ratio of APES and OCNTs, significantly improving the interfacial properties of BF/PES composites and enhancing their overall performance. After treatment with APES2/OCNTs3, the interlaminar shear strength (ILSS), flexural strength, flexural modulus, and interfacial shear strength (IFSS) reached 71.9 MPa, 379.1 MPa, 12.8 GPa, and 55.1 MPa, representing increases of 94.8 %, 64.1 %, 140.5 %, and 161.1 %, respectively. Furthermore, the enhancement mechanism and influence pattern of the APES/OCNTs hybrid sizing agent on the composite interface were thoroughly investigated. This simple, effective, and controllable method offers considerable potential for improving the interfacial bonding of BF/PES composites.

Shear performance of glued and screwed timber-steel composite connections for composite timber-steel beams

Mid- to high-rise mass timber buildings gained popularity in the last decade. Yet, engineered wood products (EWPs) used to erect these buildings have structural limitations. EWPs present brittle failure modes, particularly in bending, shear and tension, and have a low modulus of elasticity resulting in shorted spans and deeper beams relative to those in the steel and reinforced concrete counterparts. Timber-steel hybrid beams represent a potential sustainable solution to overcome these limitations by taking advantages of the high strength, stiffness and ductility of steel, and the high capacity to weight ratio of timber. However, for this solution to be structurally performant, it is essential to create effective composite action between the two materials. This study therefore compares the structural efficiency of various bonding techniques between the steel and the timber materials. Two sets of assembly solutions, representing four connection types, were proposed and experimentally investigated: (1) connecting an embedded steel plate into the timber elements by using either polyurethane (PUR) structural adhesive with two manufacturing variations or 14 G×75 mm heavy duty screws, and (2) connecting a steel plate on the surface of the timber element using either PUR structural adhesive with self-tapping M4×40 mm screws or only self-tapping screws. Softwood Laminated Veneer Lumbers (LVL) and Grade 350 steel plates were used in the experimental tests. All bonding techniques were tested in shear. The shear capacity, the slip stiffness and the failure mode were evaluated. Additionally, the efficiency of the proposed manufacturing solutions was quantified by analytically evaluate the effective bending stiffness of a timber-steel composite beam manufactured with different bonding techniques being investigated. Results indicated that the glued connections allowed a significantly more efficient composite action, with failure occurring in the timber instead of at the composite interface and near-full composite action was reached, than the screwed connections. To achieve high composite action with the screwed solutions, a large number of screws was needed which may incur high manufacturing costs.

Recent Research on the Optimization of Interfacial Structure and Interfacial Interaction Mechanisms of Metal Matrix Composites: A Review

Interfaces in metal matrix composites (MMCs) are crucial in determining the mechanical properties and functionality of MMCs. This article reviews recent scientific advances and issues related to MMC interfaces from four different perspectives: interfacial structural design, interfacial defect control, thermodynamics and kinetics of interfacial reactions, and interfacial microstructure properties‐based numerical simulation. The influence of interfacial microstructural features on interfacial strength–toughness trade‐offs and their functionality is given special attention. The interfacial problem is still one of the main challenges to be solved in the composite system, which is mainly reflected in the following aspects: interfacial microstructure–deformation mechanisms in complex systems, precise control of interfacial defects and interfacial reaction products, and the efficient and cost‐effective application of numerical simulation techniques. The integrated computation and intelligent design (artificial intelligence) of composites through multiscale computational simulation with the guidance of “interface design‐property prediction” will be the key area of MMC interface research in the future.

A Molecular Dynamics-Based Approach to Study the Effect of Covalently Bonded Modified Graphene on the Heat Transport Properties of Graphene/Natural Rubber Composite Material Interfaces.

Due to its excellent thermal conductivity, graphene can have great potential in the thermal conductivity of rubber composites. However, the interfacial thermal resistance between graphene and rubber severely hinders this application. In this work, molecular dynamics methods were used to study the interfacial thermal transport of carboxylated, aminated, hydroxylated, and oxy-bridged graphene in rubber composites. The results showed that the covalently bonded modified graphene significantly improved the thermal conductivity of the composites, with increases in thermal conductivity of 156.56%, 86.83%, 60.71%, and 44.28% and decreases in interfacial thermal resistance of 41.84%, 34.72%, 31.86%, and 16.74%, respectively. By calculating the phonon densities of states of different functionalized graphenes, it was found that covalently bonded functional groups increased the phonon match between graphene and natural rubber. However, when the degree of functionalization was greater than 11.96%, the phonon match was maintained at a stable value, which was why the covalently bonded modified graphene could significantly reduce the interfacial thermal resistance. Moreover, the graphene modified by covalent bonding was more uniformly distributed inside the natural rubber. The results of this study provide important theoretical guidance for preparing graphene/natural rubber composites with high thermal conductivity.

Jute-reinforced hybrid biocomposite incorporated with low thermal conductive silica aerogel for improved resistance to conductive and radiative heat

This study aims to develop jute-reinforced polypropylene composites by incorporating low-heat conductive silica aerogel for enhanced thermal performance, envisioning their utilization as heat-insulating panels in buildings. The fabrication of hybrid composites using a heat press molding technique showed a significant improvement in thermal properties due to incorporating aerogel into the material. The lowest obtained thermal conductivity of hybrid composite was 0.0986 W/m·K, which was almost halved (0.1704 W/m·K) to the material without aerogel. The radiative heat resistance of hybrid composites was also improved with the aerogel in the material. Additionally, composites with higher amounts of aerogel showed superior flame resistance and thermal stability at high temperatures. The hybrid composites, however, demonstrated a decrease in tensile strength due to the presence of aerogel particles at the interface of composites. The composite without aerogel displayed the highest tensile strength of 64.67 MPa, which was the lowest (47.87 MPa) for the material with the maximum amount of aerogel. The fractographic investigation also revealed the existence of aerogel particles and their random distribution at the interface of the material. The low water absorption owing to reduced interfacial vacuities and the existence of super-hydrophobic aerogel in the interior of composites indicated their durability in humid conditions without deteriorating the dimensional stability. The outcomes of the study revealed a considerable effect of aerogel on the thermal performance of composites and ascertained their excellence as a prospective heat-insulating material for conserving thermal energy by minimizing heat transfer from inside to outside of the building and vice versa.

Molecular dynamics study on the deformation mechanism of Cu–Zr/Al laminated composites

In this paper, molecular dynamics simulation was used to investigate the micromechanical behavior of the Cu–Zr/Al composite interface after rapid solidification. The effects of different Zr contents and different strain rates on the tensile strength of the Cu–Zr/Al composite interface were investigated. The results show that the tensile strength of the composite plate increased and then decreased with the increase of Zr content, and the tensile strength is the highest when the Zr content is 0.33 wt%. It was found that the plastic deformation process of the composite model at different strain rates is similar, which is divided into three stages: the expansion of stacking faults in the Cu–Zr/Al solid solution, the expansion of stacking faults successively in the Al and Cu–Zr alloy layers, and the spreading of cross - stacking faults. But the greater the strain rate is, the slower the stacking faults fracture is. So the composite model with different strain rates had different fracture modes during the tensile fracture process. When the strain rate is 0.01 ps−1 and 0.001 ps−1, it is a ductile fracture, while when the strain rate is 0.0001 ps−1, it is a brittle fracture.

Assembly of WO3-Nb2O5-ZnIn2S4 with embedded quasi-planar heterojunction characteristics and its efficient and stable dark-state photoelectrochemical cathodic protection performance

Constructing a photoanode with both high dark-state protection performance and high stability remains a top priority for photoelectrochemical cathodic protection technology, especially in a marine environment (dark-state or rainy conditions) without hole scavenging agents. In this work, we developed a class of energy-storage quasi-planar heterojunctions (WO3-Nb2O5-ZnIn2S4) with directional paths (low onset potential and well-matched energy band) and embedded morphology. The co-design of embedded and directional paths reduces the carrier transport energy barrier at the composite interface, and increases the interface contact area, thereby achieving highly stable and sensitive dark-state energy storage and photoelectrochemical cathodic protection performance in 3.5 wt.% NaCl solution without hole scavenging agent (Dark-state energy storage efficiency increased by 43%. For carbon steel, the performance retention rate is 99.6% after 500 cycles, the performance retention rate is 89% after 5000 s).

Fe2O3/In2O3 composite materials for dual-selective detection of H2S and NO2: Study on sensing mechanisms and sensing transition

Developing concise and efficient dual-selective gas sensors has been a significant challenge in sensing technology. In this study, a Fe2O3/In2O3 (FIO) composite material was successfully synthesized via a water bath method for highly efficient dual-selective detection of H2S and NO2. The enhanced dual-selectivity of the composite material is attributed to the high-quality heterojunction formed at the Fe2O3 and In2O3 interface, which provides more active sites and optimizes the electronic structure, thereby greatly improving electron transport efficiency. Consequently, this unique structure significantly enhances the gas sensing response and stability of the composite material. The optimal FIO-3 composite shows significant responses: 14.7 at 80 °C with 100 ppm H2S and 64.3 at 100 °C with 700 ppb NO2, achieving 7- and 31-fold improvements over pure Fe2O3. Analysis indicates that the dual-selective response of the FIO composite material is attributed to synergistic enhancement mechanisms, primarily controlled by high-temperature activation effects. Further density functional theory (DFT) studies reveal changes in charge density at the composite material interface, particularly facilitated by the formation of oxygen bridges promoting electron transfer from In2O3 to Fe2O3. This study offers new insights into the sensing transition of dual-selective gas sensors.

Multiscale study of interfacial properties of carbon fiber reinforced polyphthalazine ether sulfone ketone resin matrix composites

In view of the limitations of traditional research tools on interfacial failure mechanisms in fiber/PPESK composites, this work proposes a multiscale research tool to carry out an in-depth study of the interfacial behavior between fibers and matrix. Based on microdroplet debonding tests, at the mesoscopic scale, the influence of residual thermal stress on the interface damage mode is explored through finite element (FEM) simulations. The evolution mechanism of composite material interfaces in spatial and temporal dimensions is examined based on changes in interfacial stress distribution, energy dissipation, and damage morphology during the debonding process, which can be summarized as follows: accompanied by elastic-plastic deformation and friction effects, the progressive process from localized to complete failure presents a dominant Type II damage mode at the interface. To further explore the interface failure mechanism at the molecular level, an interface model of CF/PPESK composite materials was established using molecular dynamics (MD) method. By monitoring the atom movement trend, the "fiber-matrix displacement synergistic effect" in the interfacial shear damage process was revealed, thereby establishing a multiscale mapping relationship of composite material interface. Based on this, the combination of FEM and MD was utilized to investigate the interface damage process of composite materials under different service conditions and to reasonably predict the initiation and expansion of microcracks. This study provides a pioneering perspective on interface damage research in composite materials with a "top-down" multiscale approach.

Synthesis mechanism and interface contribution towards the strengthening effect of in-situ Ti5Si3 reinforced Al matrix composites

As a titanium-silicon intermetallic compound, Ti5Si3 can offer great potentials as a reinforcement agent in metal matrix composites due to its exceptional mechanical and physical properties. In this study, Ti5Si3 particles are successfully in-situ synthesized in Al-Si-Ti system through the interdiffusion reaction between Ti-Si using a powder metallurgy approach. The composites interface structure is transformed from Al/Ti5Si3 non-coherent interface to Al/TiSi/Ti5Si3 coherent/semi-coherent interface with the formation of TiSi transition layer. It enhances the interface bonding between Ti5Si3 particles and Al matrix, mitigates the mechanical differences between the matrix and the reinforcements, thereby enhancing the coordinated deformation ability. Simultaneously, the generated gradient interface between Ti@Ti5Si3 core-shell structure particles and Al matrix suppresses the rapid propagation of cracks in brittle reinforcement. As a result, the mechanical performance of AMCs is improved to 96.1 GPa for elastic modulus and 327 MPa for strength while maintaining a fracture elongation of 6.5%, which shows significantly enhancement compared with Al-5Si and Al-2.37Ti matrix. These findings establish a robust microstructural foundation for fully harnessing the strengthening effects of the reinforcements and provide a feasible technical route of utilizing the in-situ synthesized reinforcing particles for improving the mechanical performance of Al matrix composites.

Effects of Varying Nano-Montmorillonoid Content on the Epoxy Dielectric Conductivity

This study investigates the correlation between the interface structure and macroscopic dielectric properties of polymer-based nanocomposite materials. Utilizing bisphenol-A (BPA) epoxy resin (EP) as the polymer matrix and the commonly employed layered phyllosilicate montmorillonoid (MMT) as the nanometer-scale dispersive phase, nano-MMT/EP composites were synthesized using composite technology. The microstructure of the composite samples was characterized through XRD, FTIR, SEM, and TEM. Changes in the morphology of the nanocomposite interface were observed with varying MMT content, subsequently impacting dielectric polarization and loss. Experimental measurements of the dielectric spectrum of the nano-MMT/EP were conducted, and the influence of the material interface, at different nano-MMT contents, on the dielectric relaxation was analyzed. The study delves into the effect of the nanocomposite interface structure on ion dissociation and migration barriers, exploring the ionic conductivity of nano-MMT/EP. Lastly, an analysis of the impact of different nano-MMT contents on the dielectric conductivity is presented. From the experimental results, the arranging regularity of polymer molecules in the interface area raises. In the matrix, the ion migration barriers decrease significantly. The higher the MMT content in the interface, the lower the migration barrier is. Until the MMT content exceeds the threshold, the agglomerated micro-particles form, which decreases the polymers’ space distribution regularity, and the ions migration barrier raises. According to the changes in the rule of the ions migration barrier with the composite interface structure content, the reason for dielectric conductivity changes can be judged.

Enhancing Lithium‐Ion Battery Performance with Photoactive LiFePO4/CsPbBr3 Quantum Dots Composite Cathodes

AbstractThe advancement of photo‐assisted lithium‐ion batteries (LIBs) relies on developing suitable photoactive Li+ storage materials and understanding their energy storage/conversion mechanisms. A novel composite material, LiFePO4/CsPbBr3 quantum dots (LFP/CPB QDs) is presented, created by embedding CPB QDs onto LFP nanoparticles. This composite exhibits dual functionalities of photoelectric conversion and storage in LIBs. Under simulated light, the composite demonstrated significant enhancements in charge and discharge capacities, with increases of 16.8% and 16.4% at 3C, respectively. Remarkably, the coulombic efficiency exceeded 100%, reaching 115.2% when charged in the dark and discharge under light. The LFP/CPB QDs cathode also maintained 93.9% capacity retention after 200 cycles at 0.5C. Analyses with synchronous‐illumination X‐ray photoelectron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy confirmed photo‐induced charge transfer at the composite interface. Under sunlight, CPB QDs transfer photogenerated electrons to LFP, promoting the transition of Fe3+ to Fe2+ and enhancing Li+ reaction kinetics. These findings offer valuable insights for designing electrode materials for photo‐assisted battery applications.

Rebound characteristics of flexible and stiff jute rubber/epoxy hybrid composite under low-velocity impact

This present work aims to assess the low-velocity impact response of novel configuration based on jute/rubber/epoxy flexible and stiff composites having varying layup sequences using an experimental study. The Charpy and drop weight impact tests are done according to the standards. Drop weight low-velocity impact test at an energy level of 15J was performed using a conical shape impactor. Carboxylated Nitrile Butadiene Rubber (XNBR) containing carbon fillers ( N330 and N550) consisting 35 phr concentration each is used in the stacking sequence of the composite due to its high toughness and energy dissipation property. During drop weight tests conducted at a 15J energy level, the flexible RJRJR composite exhibited a peak force of 486 N, whereas the stiffer RJEJR composite demonstrated a peak force of 1075 N. The flexible composite shows no damage for the energy level tested. However, the stiff composite made using epoxy in between jute layers fails due to the matrix cracking in the composite. The peak force and specific energy absorption is dependent on stacking configuration and increases with the addition of rubber interface in the stiff composite. The energy absorption of stiff composite is higher as compared to flexible composite as indicated by the peak force.

Multilayer Gelatin-Supported BMP-9 Coating Promotes Osteointegration and Neo-Bone Formation at the n-CDHA/PAA Composite Biomaterial-Bone Interface.

The development of biomaterials capable of accelerating bone wound repair is a critical focus in bone tissue engineering. This study aims to evaluate the osteointegration and bone regeneration potential of a novel multilayer gelatin-supported Bone Morphogenetic Protein 9 (BMP-9) coated nano-calcium-deficient hydroxyapatite/poly-amino acid (n-CDHA/PAA) composite biomaterials, focusing on the material-bone interface, and putting forward a new direction for the research on the interface between the coating material and bone. The BMP-9 recombinant adenovirus (Adenovirus (Ad)-BMP-9/Bone Marrow Mesenchymal Stem Cells (BMSc)) was produced by transfecting BMSc and supported using gelatin (Ad-BMP-9/BMSc/Gelatin (GT). Multilayer Ad-BMP-9/BMSc/GT coated nano-calcium deficient hydroxyapatite/polyamino acid (n-CDHA/PAA) composite biomaterials were then prepared and co-cultured with MG63 cells for 10 days, with biocompatibility assessed through microscopy, Cell Counting Kit-8 (CCK-8), and alkaline phosphatase (ALP) assays. Subsequently, multilayer Ad-BMP-9/BMSc/GT coated n-CDHA/PAA composite biomaterial screws were fabricated, and the adhesion of the coating to the substrate was observed using scanning electron microscopy (SEM). In vivo studies were conducted using a New Zealand White rabbit intercondylar femoral fracture model. The experimental group was fixed with screws featuring multilayer Ad-BMP-9/BMSc/GT coatings, while the control groups used medical metal screws and n-CDHA/PAA composite biomaterial screws. Fracture healing was monitored at 1, 4, 12, and 24 weeks, respectively, using X-ray observation, Micro-CT imaging, and SEM. Integration at the material-bone interface and the condition of neo-tissue were assessed through these imaging techniques. The Ad-BMP-9/GT coating significantly enhanced MG63 cell adhesion, proliferation, and differentiation, while increasing BMP-9 expression in vitro. In vivo studies using a rabbit femoral fracture model confirmed the biocompatibility and osteointegration potential of the multilayer Ad-BMP-9/BMSc/GT coated n-CDHA/PAA composite biomaterial screws. Compared to control groups (medical metal screws and n-CDHA/PAA composite biomaterial screws), this material demonstrated faster fracture healing, stronger osteointegration, and facilitated new bone tissue formation with increased calcium deposition at the material-bone interface. The multilayer GT-supported BMP-9 coated n-CDHA/PAA composite biomaterials have demonstrated favorable osteogenic cell interface performance, both in vitro and in vivo. This study provides a foundation for developing innovative bone repair materials, holding promise for significant advancements in clinical applications.

Interfacial properties and mechanical performance of hybrid graphene/carbon fibre composites

The interaction zone between the matrix and the reinforcing component within carbon fibre (CF) composites plays a crucial role in influencing their performance characteristics, as extensively documented in scientific literature. Building on this fundamental knowledge, this research focuses to the investigation of the interface of fibrous composites and the effect of the incorporation of graphene nanoplatelets (GNPs) into the epoxy matrix. Through the utilization of laser Raman spectroscopy, a significant increase of over 60 % in interfacial strength with just a 2 % weight fraction of GNPs, as expressed by the enhanced shear-lag parameter observed in single fibre model composites, has been observed on model composites indicating a stronger interfacial interaction between the matrix and fibres. The effect of the incorporation of GNPs on CF-graphene interaction has been also investigated on a macroscopic level. Hybrid carbon fibre epoxy resin composite produced, by the introduction of GNPs into the polymer matrix. A series of mechanical tests were conducted, including extensive tensile testing of epoxy/graphene nanocomposite films, thorough examination of bending characteristics, and meticulous measurement of interlaminar shear strength for hybrid GNP/carbon fibre composites. These evaluations provided a clearer understanding of how the GNP integration affects the interface parameters that govern the mechanical behaviour of both the resin and carbon fibre composites.

Criterion for hydraulic fracture propagation behaviour at coal measure composite reservoir interface based on energy release rate theory

In this study, a discriminative model of fracture expansion through a composite reservoir interface was established. During fracture transformation, the model, based on the theory of energy release rate at the fracture tip, helps clarify the critical conditions and assess the law of hydraulic fracture expansion through coal composite reservoir interfaces. This model considers shear and tensile processes during fracturing at the coal–rock interface and the effects of interface material property differences on fracture extension. In addition, fracture extension pattern differentiation is achieved by comparing the hydraulic fracture tip penetration and bending energy release rates (Gp/Gd) with the ratio of reservoir fracture and interface fracture energies (ΓR/ΓF). The accuracy of this discriminant criterion was verified by comparing the predicted results of the discriminant model with fracturing test results under identical conditions. The effects of various factors on Gp/Gd and hydraulic fracture penetration extension were investigated by using the sand-mudstone composite reservoir of the Shibox Formation in the Linxing Block, China, as the geological background. The results indicate that for certain values of ΓR/ΓF, Gp/Gd increases logarithmically with an increase in water pressure in the wellbore. Moreover, the difference in ground stress and elastic modulus between the layers exponentially increases with increasing Poisson’s ratio difference and the angle between fracture and interface and decreases logarithmically with increasing fracture height. These results indicate that hydraulic fractures are likely to penetrate from reservoirs with a high elastic modulus and Poisson’s ratio into reservoirs with a low elastic modulus and Poisson’s ratio. Furthermore, hydraulic fractures are likely to penetrate formations with large differences in pinch angle and ground stress. Under specific geological conditions, high water pressure in the wellbore and small seam height are favourable for fracture penetration.

Composite electrolytes and interface designs for progressive solid‐state sodium batteries

AbstractSolid‐state sodium batteries (SSSBs) are poised to replace lithium‐ion batteries as viable alternatives for energy storage systems owing to their high safety and reliability, abundance of raw material, and low costs. However, as the core constituent of SSSBs, solid‐state electrolytes (SSEs) with low ionic conductivities at room temperature (RT) and unstable interfaces with electrodes hinder the development of SSSBs. Recently, composite SSEs (CSSEs), which inherit the desirable properties of two phases, high RT ionic conductivity, and high interfacial stability, have emerged as viable alternatives; however, their governing mechanism remains unclear. In this review, we summarize the recent research progress of CSSEs, classified into inorganic–inorganic, polymer–polymer, and inorganic–polymer types, and discuss their structure–property relationship in detail. Moreover, the CSSE–electrode interface issues and effective strategies to promote intimate and stable interfaces are summarized. Finally, the trends in the design of CSSEs and CSSE–electrode interfaces are presented, along with the future development prospects of high‐performance SSSBs.

Understanding the Carbon Additive/Sulfide Solid Electrolyte Interface in Nickel-Rich Cathode Composites and Prioritizing the Corresponding Interplay between the Electrical and Ionic Conductive Networks to Enhance All-Solid-State-Battery Rate Capability.

All-solid-state lithium batteries, including sulfide electrolytes and nickel-rich layered oxide cathode materials, promise safer electrochemical energy storage with high gravimetric and volumetric densities. However, the poor electrical conductivity of the active material results in the requirement for additional conducive additives, which tend to react negatively with the sulfide electrolyte. The fundamental scientific principle uncovered through this work is simple and suggests that the electrical network benefits associated with the introduction of short-length carbons will eventually be overpowered by the increase in bulk resistance associated with their instability in the sulfide electrolyte. However, applying just the right amount of short carbon fibres minimizes degradation of the sulfide solid electrolyte and maximizes the electron movement. Therefore, we propose the application of a low-weight-percent carbon nanotubes (CNTs) coating on the nickel-rich cathode LiNi0.8Co0.1Mn0.1O2 (NCM811) along with large-aspect-ratio carbon nanofibers (CNFs) as the primary conductive additive. When only 0.3 wt % CNTs was utilized with 4.7 wt % CNFs, an initial Coulombic efficiency of 83.55% at 0.05C and a notably excellent capacity retention of 90.1% over 50 cycles at 0.5C were achieved along with a low ionic resistance. This work helps to confirm the validity of applying short carbon pathways in sulfide-electrolyte-based cathode composites and proposes their combination with a larger primary carbon additive as a solution to the ongoing all-solid-state battery rate and instability issues.

Atomic insight on the electronic structure and interfacial bonding characterization of the Cu/TiC interface

The interfacial bonding characteristics of ceramic reinforced phase and metal matrix in metal matrix composites have a significant impact on their strength. Herein, the interfacial bonding properties and alloy element doping of the Cu/TiC interface in TiC-reinforced Cu matrix composites with a stoichiometric ratio of TiC of 1:1 were investigated by atomistic DFT simulations. The analysis of twelve Cu/TiC interfacial models reveals that the TiC(111) in Cu/TiC interface with C-terminated is more stable than that of TiC(111) interface with Ti-terminated due to the stronger covalent bonds formed by Cu-C. The Cu(110)/TiC(111)-C interface with the highest work of adhesion (2.871 J/m2) is the most stable interface among these Cu/TiC interfaces. Moreover, the Cu-Co/TiC interface has the highest Wad (4.223 J/m2) compared to Cu/TiC, Cu-Ni/TiC, and Cu-Zn/TiC interfaces. And the Cu-Zn/TiC interface has the lowest Wad (2.092 J/m2), which is even lower than that of the Cu/TiC interface (2.306 J/m2). During interfacial tension, the Cu/TiC, Cu-Ni/TiC, and Cu-Zn/TiC interfaces start to fracture either at the interface layer or the sub-interface layer on the Cu side, while the Cu-Co/TiC interface begins to fracture within the Cu slab. The Cu-Co/TiC interface has the highest tensile strength of 20.12 GPa at14 % strain compared to Cu/TiC (14.76 GPa), Cu-Ni/TiC (16.35 GPa), and Cu-Zn/TiC (15.30 GPa) interfaces, which is attributed to the strengthening of both the interface and sub-interface by Co doping. Thus, Co doping in the Cu matrix significantly strengthens the Cu/Ti interfacial bonding, Ni doping has a weaker strengthening effect, and zinc doping weakens the interfacial bonding.