Areal Weight Research Articles

The effect of interlining’s structure on the stress relaxation of laminated fabrics in terms of loading direction

In order to improve the performance and formability of the garment, it is necessary to laminate the fabrics using adhesive interlinings with different structures. Since the garment is used over long and repetitive periods of time, the study of time-dependent mechanical behavior of the laminated structures used in garments is important. In this study, woven, knitted and nonwoven interlinings with similar areal weight range were utilized for lamination and the tensile stress relaxation behavior of each interlining, face fabric and the laminated structure was investigated. Moreover, with the aim of investigating the effect of tensile force direction on the stress relaxation behavior, tensile property and stress relaxation were measured at various loading directions of 0°, 30°, 45°, 60° and 90°. The stress relaxation behavior of different samples was measured at two levels of strains in the elastic and plastic region and the effect of interlining structure and direction of tensile load application, on stress relaxation was evaluated. The results indicated that fabric lamination would lead to an increased strength. Besides, the effect of loading direction on tensile behavior and stress relaxation was significant. In general, increasing the applied strain level leads to an increase in the stress relaxation value. Finally, it was shown that among various viscoelastic models used for the interpretation of the stress relaxation of interlinings and laminated fabrics, the two component Maxwell model had the best correlation with the experimental results.

Structural health monitoring of scarf bonded repaired glass/epoxy laminates interleaved with carbon non-woven veil

Bonded repair patches/joints often introduce vulnerabilities in composite laminates, making them prime candidates for structural health monitoring (SHM). In this study, stepped-scarf bonded joints were manufactured using glass fibre-reinforced epoxy laminates as representative repair patches, and a novel SHM approach through the electrical resistance change method was applied. To establish an electrically conductive path within the stepped-scarf joint, non-woven carbon fibre veils with areal weights of 10 g/m² and 20 g/m² were interlaid along the stepped bondline. Two types of tensile tests were performed. In the first set of tests, the stepped-scarf joints underwent monotonic quasi-static tensile loading until the bondline was completely fractured (catastrophic failure) and the change in electrical resistance was continuously monitored. The failure stress of the joint with a 10 g/ m² carbon veil was only marginally decreased (∼2 %) in comparison with that of the joints without a carbon veil, while the failure stress of the joint with a 20 g/m² carbon non-woven veil was considerably decreased (by ∼9 %). However, the joints with 10 g/m² and 20 g/m² carbon veils exhibited a significant change in electrical resistance (∼200 % and ∼1000 %, up to full failure, respectively). Simultaneously, the change in electrical resistance was used for the detection of damage initiation and progression, supported by digital images taken during the tests. In the second set of tests, the joints were subjected to a cyclic tensile loading/unloading regime and the change in electrical resistance was monitored. A significant amount of permanent change in resistance during the unloading phases (up to 120 % in the bondline with a 20 g/m² veil) was observed, providing insights into the laminate and bondline damage evolution. In addition, thermal images obtained with the joule heating method in the cyclic tensile tests were used to confirm the damage detected with the electrical resistance change method. Moreover, the micrographs from the fracture surfaces indicated that the variations in electrical resistance change are largely caused by damage occurring within or near the carbon veils. In conclusion, the results demonstrate that the presented SHM approach, which incorporates carbon non-woven fibre veils within non-conductive laminate composites, holds promise for monitoring damage initiation and propagation in repaired composite laminates as well as adhesively bonded composite laminate joints, without adversely influencing the structural integrity of the bondline.

Multi-scale characterization of self-sensing fiber reinforced composites

The piezoresistive properties of fiber-based embedded sensors across tow, fabric, and laminate scales offer opportunities for their efficient application in fiber reinforced polymer composite (FRPC) structures. This study involves the multi-scale characterization of rGO-coated glass fiber tows, fabric, and laminates produced via vacuum assisted resin transfer molding (VARTM). The study demonstrates how fiber type, areal weight, and architecture affect piezoresistivity in rGO-coated glass fiber-based sensors subjected to in-plane tensile loading. In this study, rGO-coated glass fiber tows, with three linear densities (138, 1200, 1232 TEX), were examined. Fabric-level sensors, including plain weave (PW), and quadriaxial (QUAD), with areal densities of 200, 600, and 807 g/m2 were also studied. For comparison, laminates using UD carbon fabrics (300 g/m2) were employed as embedded piezoresistive sensors in the glass fiber-based laminates. It has been shown that rGO-coated sensors with lower areal weights outperformed all other sensor types in terms of their piezoresistive characteristics. This study suggests that piezoresistive sensors offer significant potential for use in load-bearing structural applications which can be further enhanced by investigating their lower scales.

Interlaminar toughening of carbon fiber/epoxy composites via interleaving co‐polyamide (Co‐PA) veils

AbstractThermoplastic veil interlayers offer a promising approach to improve interlaminar reinforcement in composite materials. This study investigates co‐polyamide (Co‐PA) interleaved veils, fabricated through the hot melt adhesive (HMA) technique. These veils are then applied with varying areal weight densities as interleaves to simultaneously toughen and strengthen carbon fiber/epoxy (CF/EP) composites, utilizing the vacuum‐assisted resin infusion (VARI) method. Integrating Co‐PA veils with a low melting point in the interlaminar of CF/EP composites improves compatibility and promotes strong adhesion between thermoplastics and epoxy resins. As result, The Co‐PA laminates exhibited significant improvements compared with the untoughened composites, with a maximum enhancement of 148.1% and 67.8% for Mode‐I (GIC) and Mode‐II (GIIC), respectively. Moreover, ILSS, tensile strength, and flexural strength improvements were also 20.9%, 34.9%, and 14.5%, respectively. The fracture surface analysis via scanning electron microscopy directly revealed the crack propagation on the fracture surfaces of Mode‐I and Mode‐II specimens. This analysis revealed that Co‐PA demonstrated excellent compatibility with epoxy resin, melts during the stage of epoxy curing, and undergoes phase separation in the later stage, resulting in the formation of “bead‐like” structures within the fibrous network. Remarkably, this structure significantly enhanced the toughness of the CF/EP composites. The Co‐PA veils can improve the interlaminar toughness of CF/EP composites due to their compatibility with the epoxy matrix and high inherent toughness and strength. This method is straightforward to manage and can be utilized for manufacturing large‐scale composite materials incorporating CF fabrics, demonstrating promise for industrial applications.Highlights With its low melting point, co‐polyamide helps prevent structural failure or excessive damage and is proposed to be utilized in composites to enhance the interlaminar fracture toughness properties. The effects of Co‐PA veils of different areal densities on the mechanical characteristics of interlaminar composites were examined. Co‐polyamide particles with fiber‐carbon laminates offer superior fatigue properties and an optimum carbon fiber‐bridging mechanism. Co‐polyamide veils with CF/EP laminates are feasible for structural use in high‐tech automotive applications.

A genetic algorithm's novel rainfall distribution method for optimized hydrological modeling at basin scales

ABSTRACT Rainfall has a dominant role in rainfall-runoff models, with the rendering of these models depending both on the accuracy of the data and on the way that rainfall is spatially allocated. The research proposes a methodological framework where a genetic algorithm (GA)-based method responsible for the spatial distribution of gauge observations at the basin scale is coupled with the HEC-HMS hydrological model to produce simulated discharges of high accuracy. The custom-developed GA is used to divide a 2D space, adhering to specific criteria, into polygonal geometries that represent gauge zones of influences, similar to the Thiessen polygon method concept. Consequently, a collection of vectorial polygonal areas, equivalent in number to the employed monitoring stations, is produced with the areal weights to be used for distributing the rainfall across the case study basin and subsequently to force the hydrological simulations. The generated gauge weights are validated for a different temporal precipitation event. The final outputs expressed through a series of statistical measures, clearly demonstrate the effectiveness of the specific methodology (e.g. R2 and Nash–Sutcliffe are larger than 0.83 and 0.73). The methodology can foster accurate hydrological simulations, especially in cases where there is a limited number of rainfall stations and corresponding observations.

Assessing the Sound and Heat Insulation Characteristics of Layered Nonwoven Composite Structures Composed of Meltblown and Recycled Thermo-Bonded Layers.

Sound and heat insulation are among the most important concerns in modern life and nonwoven composite structures are highly effective in noise reduction and heat insulation. In this study, three layered nonwoven composite structures composed of a recycled polyester (r-Pet)-based thermo-bonded nonwoven outer layer and meltblown nonwovens from Polypropylene (PP) and Polybutylene terephthalate (PBT) as inner layers were formed to provide heat and sound insulation. Fiber fineness and cross-section of the thermo-bonded outer layer, fiber type (PP/PBT), areal weight (100/200 g/m2) and process conditions (calendared/non-calendared) of the meltblown inner layer were changed systematically and the influence of these independent variables on thickness, bulk density, air permeability, sound absorption coefficient and thermal resistance of composite structures were analyzed statistically by using Design Expert 13 software. Additionally, the results were compared with composite structures including an electrospun nanofiber web inner layer and with structures without an inner layer. It was concluded that comparable or even better sound absorption values were achieved with the developed nonwoven composites containing meltblown layers compared to nanofiber-included composites and the materials in previous studies.

Electrospun nanofiber interleaving through double infusion method to induce pseudo‐ductile damage resistance response in carbon/epoxy composites

AbstractCarbon composites are susceptible to invisible damage development such as matrix cracking, fiber kinking, and interfacial debonding upon external transverse loading. These incipient damages may interact to evolve into life‐limiting delamination propagating both in in‐plane and transverse directions. This study addressed that by interleaving carbon/epoxy composites with electrospun nylon 6 nanofibers adopting a double infusion method. Damage resistance results showed that the optimum nanofiber areal weight (17.35 g/m2) offered a 27% improvement in specific total toughness. The emergence of pseudo‐ductility substantially enhanced the plastic toughness (46.15%) of interleaved composites. The load required for initial matrix cracking was 65.49% higher, and number of matrix cracking events was suppressed by 84.11% at the optimum areal weight of interleave. Fractography revealed frequent interlaminar crossings and delamination crack bridging as two major toughness mechanisms. Both the external damage area and delaminated area increased with increment in nanofiber areal weight.Highlights Electrospun nanofibre interleaved carbon/epoxy composites were fabricated through a double infusion method to characterize damage resistance. Acoustic data of matrix cracking was rationalized to show the effectiveness of nanofiber interleaves in suppressing this damage type. Microstructural factors and mechanisms contributing to the improved toughness of optimally interleaved composites were identified. External damage/delaminated areas of interleaved composites were correlated with nanofiber areal weights.

UAV 3-D path planning based on MOEA/D with adaptive areal weight adjustment

UAV 3-D path planning based on MOEA/D with adaptive areal weight adjustment

Ballistic performance of bio-inspired hybrid interleaved composite structures suitable for aerospace applications

We investigate the ballistic performance of an aircraft engine containment casing demonstrator, made of composite materials with a novel bio-inspired hybrid interleaved design, under high-velocity impact (HVI) at a specific angle. Firstly, we apply a bio-inspired (BI) helicoidal design to develop a large-scale monolithic laminate concept made of carbon fibre-reinforced polymer (CFRP). Then, we hybridise the developed BI laminate concept with interleaved blocks of Zylon fibre (PBO)-reinforced polymer to develop a large-scale BI hybrid interleaved laminate concept. We then further hybridise the developed BI hybrid concept with titanium (Ti) foils (located at the impact face) so that in total we have three large-scale laminate concepts. We manufacture 6 large-scale laminates from each concept with dimensions of 225 × 225 mm and a target areal weight of 0.95 g/cm2. We then test them (perpendicularly) under HVI ranging from 150 to 300 m/s to obtain the ballistic limit and energy dissipation. Secondly, after selecting the best-performing developed laminate concept, we scale it up to develop industrial demonstrator panels with a target areal weight of 1.5 g/cm2 and dimensions of 550 × 360 mm. We test the panels under HVI at an angle of 55° with a larger and heavier projectile, to more closely represent a fan blade-off event onto the engine casing. The results of the large-scale laminate concept tests show that the BI hybrid interleaved CFRP/PBO concept outperformed the rest of the concepts with 54% and 34% improvement in energy dissipation compared to that of quasi-isotropic (QI) and the BI monolithic CFRP, respectively. Our results show that small-scale designs for HVI-resistant CFRP-based laminates cannot be simply assumed to exhibit an equivalent performance for industrial applications with thicker laminates, heavier projectiles and impacts at an angle.

Suppression of compression induced delamination in tapered laminated composites using a ply scarfing method

Thickness tapering of composite laminates is a common strategy for efficient and lightweight composite structures. The termination of specific plies necessary to achieve such tapering is well known to introduce sites for delamination initiation in laminates. This propensity for delamination is highly dependent on the thickness of the terminated ply, which presents a significant challenge in using thicker materials to improve the production rate of large-scale composite structures.In this work, the effectiveness of ply scarfing in improving the compressive failure stress of tapered laminates made using thick, unidirectional non-crimp fabrics (NCF) was experimentally investigated for the first time. Unidirectional tapered laminates were manufactured using two different NCFs with fibre areal weights of 620 and 1070 g/m2 via resin infusion. Specimens made of the 1070 g/m2 material which incorporated a ply terminated using the ply scarfing method were compared with those including plies terminated using the conventional ply-drop method. which incorporated a ply terminated using the ply scarfing method. The compression failure behaviour of the specimens was analysed using a high-speed camera. The results showed that ply scarfing suppressed delamination of the belt plies under compression and increased the failure stress by ∼60%. Furthermore, the tapered geometry of the terminated ply’s end was effective in preventing the void entrapment at the ply drop and significantly reducing the manufacturing variability.

The effect of marine environment on the mechanical performance of Dacron sailcloth

The usage of sails is increasing parallel to the sustainability initiatives in marine transportation not only for recreational craft but also for large vessels carrying commercial goods and passengers. In this study, the marine environmental degradation of the sailcloth which significantly shortens the lifetime of these materials was investigated experimentally. Dacrons, which are relatively cheap, easy to form, and resistant to breakdown, but problematic to keeping their original shape while subjected to wind loads, were selected as the sailcloth. The combined effect of seawater exposure, temperature, UV, wet-dry cycle, water repellent treatment on the Dacron’s mechanical performance was measured by tensile tests performed for the Dacron specimens with nine different areal weights and in two different fibre directions (warp and weft) and by dynamical mechanical analysis for a representative Dacron sailcloth. The comparative results show that the marine environment has significant degradation effects on the mechanical performance of sailcloths.

Scalable, roll-to-roll manufacturing of multiscale nanoparticle/fiber composites using electrophoretic deposition: Novel multifunctional in situ sensing applications

Multiscale composites, where traditional fiber reinforcements are combined with nanoscale reinforcements, have emerged as multifunctional materials and have found potential for in situ strain and damage sensing, and energy harvesting/storage applications. Critical to the advancement of future applications is the development of manufacturing techniques that are industrially scalable. Electrophoretic deposition (EPD) can uniformly coat functionalized nanoparticles, such as carbon nanotubes (CNT), on conductive and non-conductive fiber substrates, producing multiscale composites with controlled microstructures and functional properties. In this research, a pilot-scale roll-to-roll EPD system is developed to continuously manufacture CNT-integrated fabrics for in situ sensing applications. Based on fundamental knowledge of CNT deposition mechanisms, key experiments are conducted to determine electrode configurations to optimize deposition yield in the roll-to-roll process. Functionalized CNTs are then deposited on 4–6 m long continuous rolls of randomly oriented non-woven glass fiber veil with different areal weights, and the CNTs form a continuous, conductive fiber-level coating. The thin and open fabric microstructure allows embedded sensors that are minimally invasive to the composite structure and allow ultraviolet (UV) light transmittance for use with UV-curable resins. The electrically conductive CNT network created on the fabric allows for the integration of sensing functionality. Short beam specimens with the CNT sensors embedded at the midplane showed no deterioration in strength. Multiple functionalities, including strain sensing and flow/UV cure monitoring during vacuum infusion are demonstrated. Sensors tested under flexural loading demonstrated sensitivity in tension and compression, and during resin infusion, the sensors could track resin flow and cure progression.

A Multi-Material Flame-Retarding System Based on Expandable Graphite for Glass-Fiber-Reinforced PA6.

A synergistic multi-material flame retardant system based on expandable graphite (EG), aluminum diethylphosphinate (AlPi), melamine polyphosphate (MPP), and montmorillonite (MMT) has been studied in glass-fiber-reinforced polyamide 6 (PA6). Analytical evaluations and fire performances were evaluated using coupled thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) as well as cone calorimetry, UL-94 fire testing, and limiting oxygen index (LOI). A combination of EG/AlPi/MPP/MMT has been shown to provide superior flame-retarding properties when integrated at 20 wt.% into glass-fiber-reinforced PA6 (25 wt.%), achieving UL-94 V0 classification and an oxygen index of 32%. Strong residue formation resulted in low heat development overall, with a peak heat release rate (pHRR) of 103 kW/m2, a maximum of average heat release rate (MAHRE) of 33 kW/m2, and deficient total smoke production (TSP) of 3.8 m2. Particularly remarkable was the structural stability of the char residue. The char residue could easily withstand an areal weight of 35 g/cm2, showing no visible deformation.

Development and characterization of thermal and electro-active shape memory polymer composites using polyester fabric to obtain a large bending effect

In this work, thermally active (TA) and electro-active (EA) shape memory polymer composites (SMPCs) were prepared. The recycled polyester fabric (RPF) with three different areal weights (low, medium, and high) was used as a reinforcement to get a large bending effect in SMPC, due to its low rigidity. The TA-SMPCs were fabricated by hand layup, while unidirectional (UD) carbon tow inserts were used between two layers of polyester fabric for EA-SMPCs. The shape memory (SM) and shape recovery (SR) capability of all TA-SMPCS were investigated at different temperatures (50°, 75°, and 100 °C). Whereas the EA-SMPCs were investigated at 50 °C. The maximum achieved SR and shape fixity ratios of developed TA-SMPCs were 100 % and 99 %, respectively. The EA-SMPCs also showed 100 % SR ratios. The surface morphology of the developed composites was studied using an optical microscope. Delamination was observed in 3-layered TA-SMPCs and EA-SMPCs at 50 °C after cyclic loading when prepared with higher areal-weight fabrics.

Study on the sound absorption of jute fabrics: effects of woven factors and multilayer structures

As porous materials, textiles have been widely used in noise reduction and control engineering due to the advantages of lightweight and easy processing. In this work, the effects of structural factors and physical properties of woven jute fabrics on sound absorption were investigated. Woven jute fabrics with different warp and weft density, thickness, areal weight, and bulk density are employed for acoustical impedance tube measurement, and the warp and weft flexural rigidity, and air permeability of woven jute fabric were measured. The relationship between structural characteristics and sound absorption properties was studied, which has provided good reference for the design of fabric texture. Furthermore, multilayered structure was also constructed by facile plying-up method, followed by the evaluation on the effects of various layering configuration, and then for improved sound absorption. This investigation has mainly focused on woven factors and physical properties, which is benefit to the fabrication of woven jute fabrics with optimal structural details for enhanced sound absorption.

Effect of Fabric Areal Weight on the Mechanical Properties of Composite Laminates in Carbon-Fiber-Reinforced Polymers

The present work aims at studying the effect of the reinforcing fabric areal weight on the mechanical properties of composite laminates in carbon-fiber-reinforced polymers. Three different pre-impregnated 2 × 2 twill weaves, characterized by the different areal weight values of 380, 630, and 800 g/m2 were used to produce laminates. These areal weights were selected to represent typical values used in structural application. A hand lay-up technique followed by an autoclave cycle curing was employed to produce the laminates. The desired final thickness of the laminates was obtained by laying-up a different ply number, as a function of the areal weight and thickness of each fabric. Uniaxial tensile and in-plane shear response tests were performed on samples obtained from laminates after curing. Furthermore, the presence of voids in composite materials were detected by performing resin digestion tests. Finally, light optical microscopy and stereomicroscopy analyses allowed observing the different arrangement of the plies in the cross-sections of laminates after curing and evaluating the degree of compaction as a function of the reinforcing fabric used. It was demonstrated that the fabric areal weight significantly affects the mechanical performances of the composite laminates; specifically, the decrease in the areal weight of the twill weave leads to an increase in tensile strength, elastic modulus, and in-plane shear stress, i.e., of about 56.9%, 26.6%, and 55.4%, respectively, if 380 g/m2 and 800 g/m2 fabrics are compared. These results are crucial for an optimal material selection during the design process for industrial applications and help to better understand composite material behavior.

Bio-inspired interleaved hybrids: Novel solutions for improving the high-velocity impact response of carbon fibre-reinforced polymers (CFRP)

We propose a novel design methodology consisting of bio-inspired (BI) and interleaved layups to develop hybrid carbon fibre-reinforced polymer (CFRP) composite structures for improved high-velocity impact (HVI) performance. Firstly, we apply a BI helicoidal design method consisting of various pitch angles (considering both thick- and thin-ply CFRP) to develop BI monolithic CFRP laminates. Secondly, we apply the interleaving design method to develop BI hybrid CFRP-based laminates interleaved with blocks of BI Zylon fibre-reinforced polymers through the thickness. We evaluate their response and compare it with traditional quasi-isotropic (QI) hybrid bulk layups. In addition to hybridising with Zylon, we apply titanium (Ti) foils to both the monolithic and hybrid CFRP-based laminates to investigate and compare their response. For all our hybrids, we kept the ratio of the hybridising material(s) to be less than 50% to ensure suitable in-plane mechanical properties and aimed at a target areal weight of 0.95 g/cm2. We also manufactured QI thick- and thin-ply monolithic CFRP laminates as baselines. We tested all laminates at 170 and 210 m/s and studied their response and failure modes. Our results show that the average energy dissipation of the QI monolithic thin-ply baseline improved by up to 22% by changing the layup from QI to BI, and by about 118% by changing the baseline QI layup to BI hybrid interleaved. Post-mortem analysis reveals that there are additional failure mechanisms activated in the BI hybrid interleaved layup with respect to the baseline.

Novel zone-based hybrid laminate structures for high-velocity impact (HVI) in carbon fibre-reinforced polymer (CFRP) composites

We propose novel zone-based hybrid laminate concepts for improving the high-velocity impact (HVI) response of baseline carbon fibre-reinforced polymer (CFRP) composites while maintaining similar areal weights and retaining substantial in-plane mechanical properties by requiring that about 80% (by mass) of the baseline CFRP is kept in the hybrid concepts. We identify three zones along the thickness of the laminate according to their role during HVI and implemented tailored materials in these zones to improve the HVI response. We studied a wide range of materials, including: fibre reinforcements of carbon (thin- and thick-plies), glass, Zylon and ultra-high molecular weight polyethylene (UHMWPE); a shape memory alloy/carbon fabric; and ceramic, alumina and titanium sheets. All laminate concepts have similar areal weights for a meaningful comparison. After defining the various concepts, we manufactured and measured their specific dissipated energy under HVI, and finally carried out post-mortem analysis (including C-scan and microscopy). The results show up to 95% improvement in energy dissipation over the baseline quasi-isotropic (QI) CFRP configuration.

Mechanical and Viscoelastic Properties of Carbon Fibre Epoxy Composites with Interleaved Graphite Nanoplatelet Layer

The use of interleaving material with viscoelastic properties is one of the most effective solutions to improve the damping capacity of carbon fibre-reinforced polymer (CFRP) laminates. Improving composite damping without threatening mechanical performance is challenging and the use of nanomaterials should lead to the target. In this paper, the effect of a nanostructured interlayer based on graphite nanoplatelets (GNPs) on the damping capacity and fracture toughness of CFRP laminates has been investigated. High-content GNP/epoxy (70 wt/30 wt) coating was sprayed on the surface of CF/epoxy prepregs at two different contents (10 and 40 g/m2) and incorporated at the middle plane of a CFRP laminate. The effect of the GNP areal weights on the viscoelastic and mechanical behaviour of the laminates is investigated. Coupons with low GNP content showed a 25% increase in damping capacity with a trivial reduction in the storage modulus. Moreover, a reduction in interlaminar shear strength (ILSS) and fracture toughness (both mode I and mode II) was observed. The GNP alignment and degree of compaction reached during the process were found to be key parameters on material performances. By increasing the GNP content and compaction, a mitigation on the fracture drop was achieved (−15%).

Performance of Air Electrode Catalysts in the Presence of Redox Mediators for High-Capacity Li–O2 Batteries

Lithium–oxygen batteries (LOBs) have usually been investigated at low current densities and low areal capacities due to small amounts of active materials supported on carbon papers, though they theoretically have high energy density. In addition, studies on catalysts have usually been conducted in the absence of redox mediators. In this study, we have investigated various catalysts at a high current density (0.4 mA cm–2), at a high areal capacity (4 mAh cm–2), and in the presence of dual redox mediators (RMs) of NO3– and Br–, using Ketjen black free-standing sheets (KBFSs; thickness: 270 μm) of high areal weight (6 mg cm–2). The RMs reduced the charge overvoltage even in the presence of catalysts, and catalysts also promoted Li2O2 decomposition in the presence of RMs. RuO2/KBFS, Ir-Co/N-KBFS, and Co/KBFS improved both cyclability and overvoltages compared with KBFS. RuO2/KBFS and Ir-Co/N-KBFS decomposed Li2CO3 at lower voltages than KBFS and exhibited less Li2CO3 residue after charge than KBFS. However, catalysts were coated with byproducts even in the presence of RMs during the discharge/charge tests.