Graphene Nanoplates Research Articles

Preparation and Thermal Performances of Lauric Acid/Polyvinyl Butyral/Graphene Nanoplates Composite Phase Change Materials

In recent years, there has been significant progress in the development and application of phase change materials (PCMs) for thermal energy storage. The new lauric acid (LA)/polyvinyl butyral (PVB)/graphene nanoplates (GNP) composite phase change materials (CPCM) are prepared using the solution blending method, in which LA acts as PCM, PVB serves as support material, and GNP is used as thermally conductive enhancer. The prepared CPCM with 80 wt% LA can retain stable shape without leakage. The Fourier‐transform infrared and X‐ray diffractometer results indicate that there is no chemical reaction among the various components of the CPCM. The differential scanning calorimeter results show the CPCM3 (with 80 wt% LA and 5 wt% GNP) has melting latent heat of 134.41 KJ Kg−1 with melting temperature of 41.73 °C. The thermal conductivity tests present that thermal conductivity of CPCM3 is 0.689 W (m K)−1, which is 3.83 times that of the PCM2. The thermogravimetric analyzer results verify that the CPCM possess good thermal stability within the operating temperature range of 35–45 °C without any degradation. The thermal cycling tests indicate that CPCM have good thermal reliability. Therefore, it has promising applications in building energy conservation, solar thermal systems, thermal management, and textiles.

Inherent resonance of carbon and graphene-based nanocomposite coupled single-span arch beams

In recent decades, there has been a significant rise in the utilization of composite materials for various engineering applications. These advanced materials offer the potential to improve the mechanical properties and vibration characteristics of structural components. This particular study is dedicated to enhancing the vibration performance of coupled curved-curved beams that feature a linear elastic mid-layer, achieved through the incorporation of carbon nanotubes (CNTs), graphene nanoplates (GNPs), and graphene oxide powder (GOPs). The governing equations of the system are solved using the generalized differential quadrature (GDQ) method. While previous research primarily focused on the use of CNTs to enhance the vibration behavior of coupled-curved beams, this study delves into the utilization of multiple nanofillers for this purpose. An essential aspect of modeling composite materials lies in determining their equivalent mechanical properties. This research undertakes a comparison between the rule of mixture (RoM) and Halpin-Tsai methods for calculating these properties, revealing that frequencies derived from the RoM method are higher than those obtained through the Halpin-Tsai approach. Additionally, the study highlights that systems incorporating GNPs demonstrate higher frequencies at lower nanofiller volumes, with CNTs and GOPs following in ranking. However, this hierarchy shifts at higher nanofiller volumes. The arrangement of nanofillers within the system is influenced by its boundary conditions, with the curvature of the bottom beam playing a significant role in affecting vibration behavior. Increasing the radius of the bottom beam (R2) leads to higher system frequencies, which subsequently decrease with higher R2 values.

Fabrication of GNPs sprayed carbon fiber and its effects on the interfacial and mechanical behavior of reinforced epoxy multiscale laminated composite

AbstractThe current research compares the effects of modifying carbon fiber [via spraying graphene nanoplates (GNPs)] and/or GNPs reinforcement on the mechanical and interfacial behavior of carbon fiber epoxy composites. Using a spraying method, the epoxy matrix was reinforced, and carbon fiber was modified with 0.2 and 1 wt% of GNPs, respectively. Tensile, interlaminar, and dynamic mechanical analyses (DMA) tests were conducted on the composite to assess the role of GNPs in enhancing mechanical, interfacial, and thermomechanical properties. The obtained results indicate that the spraying technique effectively enhanced the ultimate tensile strength (UTS) and interlaminar fracture toughness (ILFT) of the composite. The UTS improved by 31%, while the ILFT significantly improved by 38%. Additionally, assessing the modulus gradient through the interface shows improved interfacial interaction between modified carbon fiber and reinforced epoxy. Scanning electron microscopy examination of the fractured surfaces indicated that the existence of nanofillers with high surface area contributed to significant improvements in adhesion between the modified fiber and reinforced epoxy matrix, leading to enhanced interfacial, mechanical, and thermomechanical properties of CFRPs for structural applications.Highlights Incorporation of surface modified carbon fibers and GNPs reinforcement in the epoxy matrix to enhance the interfacial interaction. Evaluation of the effects of GNP nanofiller on interfacial and mechanical performance of the composite. Fracture surfaces in ILSS, tensile, and mode I test were analyzed using FESEM. Utilization of nanoscale modulus mapping for the fiber‐matrix interface assessment.

Featuring vertical channel structure through directional solidification method to endow GNP-aerogels with enhanced ultra-electromagnetic wave absorption

Three-dimensional (3D) carbon-based electromagnetic waves absorbing materials (EWAMs) have garnered significant attention due to high electrical conductivity, high dielectric loss, low density, and improved characterization of impedance matching. However, there is a paucity of research on the design of material structures. In this regard, we proposed the graphene nanoplates (GNPs) EWAMs featuring a vertically aligned channel structure through liquid nitrogen rapid directional solidification and freeze-drying techniques. By utilizing methyl cellulose (MC) as a binder to modify the internal ice crystal structure, an exceptional electromagnetic waves (EWs) absorption material exhibiting excellent impedance matching characteristics and demonstrating multiple polarization phenomena were created. Notably, the material showcased superior absorption performance with a minimal reflection loss (RLmin) of −57.20 dB. Furthermore, the pre-solidification slurry possesses remarkable plasticity, facilitating the fabrication of various complex structures for EWAMs during directional solidification. This method provides novel insights for future exploration and fabrication of tuneable frequency band EWAMs.

Utilizing Upcycled Graphene Nanoplatelet-Coated Glass Fibers as a Performance Booster and Compatibilizer for Enhanced Mechanical Performance of Polypropylene/Glass Fiber/Graphene Nanoplatelet Composites.

The high usage ratio and elevated density of glass fibers (GFs), often surpassing twice that of polymers, can contribute to undesired increases in the overall density of polymeric materials. One potential solution is the incorporation of graphene as a secondary additive, offering a lower specific gravity and exceptional mechanical properties. In light of this, waste tire-derived graphene nanoplates (GNPs) were optimized for coating onto GFs by considering factors such as surface treatment of the fiber, the dispersion quality of GNP, and the coating technique. The resulting GNP-coated GF (GNP-c-GF) was initially incorporated into pure polypropylene (PP) at low weight percentages (0.1-1 wt %), and 31% increase in the tensile modulus was achieved compared to neat PP. Subsequently, 1 wt % GNP-c-GF was utilized as a compatibilizer in PP/GF/GNP composites to enhance the compatibility between GNP and GF. By strategically incorporating GNP and GNP-c-GF at a lower GF ratio, the detrimental impact on the tensile modulus of 30% GF-filled PP was effectively mitigated, leading to a remarkable enhancement to an impressive value of 5658 MPa. The successful integration of GNP and GNP-c-GF exemplifies their promising potential as additives for achieving superior mechanical properties in composite materials, while concurrently promoting the utilization of recycled content.

Influence of graphene nanoplates and titanium diboride particulate on wear and interfacial bonding properties of sintered aluminium alloy composites

Graphene has been considered an appropriate reinforcing filler for aluminium/titanium metal matrix composites due to its outstanding strength and stiffness and its exceptional thermal and electrical properties. The variable concentrations of graphene nanoplates (GNPs) was considered in this research, such as 2 %, 4 %, 6 % and 8 %, for determining wear properties and interface bonding aluminium alloy composites. The graphene-reinforced Al 7075/10 % TiB2 hybrid nanocomposite samples were produced using ball milling and pressure-less vacuum sintering process. The wear loss was investigated for all the variable graphene concentration samples with respect to wear load and sliding distance by pin-on-disk method and optimum concentatrion of GNPs was obtained by design of experimental (DOE) analysis. Further, Field Emission Scanning Electron Microscopy (FESEM), Elemental mapping, Energy Dispersive X-ray (EDX), and microhardness tests were utilized to analyze the graphene-reinforced Al 7075/10 % TiB2 hybrid nanocomposites, It was concluded that the wear resistance and microhardness of Al/10 % TiB2/4 % GNPs increased by 71.3 % and 17.6 %, respectively, compared with non-hybrid aluminium alloy materials. Moreover, a Transmission Electron Microscope (TEM) has been used to investigate the interfacial strength of aluminium alloy composites. The wear loss characteristics was also optimized using and central composite design (CCD) of response surface methodology (RSM).

Advances in self-sensing cement-based composites containing nano materials for smart civil infrastructures

Self-sensing cement-based composites incorporating the carbon nanotubes (CNTs) and graphene nanoplates (GNPs) with dosages of 0.0 ～ 5.0 vol% are developed for their favourable properties. The mechanical behaviors, electrical conductivity, and piezoresistivity of these composites are investigated comprehensively. Furthermore, modification mechanisms of the CNTs and GNPs affect performances of these composites are explored in-depth. The results show that the absolute maximum FCR/stress sensitivity/strain sensitivity is reached up to 53 %/0.69 %·MPa−1/119.3 with content of the CNTs and GNPs is 3.0 vol%. Moreover, its compressive strength/ultimate strain/modulus of elasticity is achieved at 77.1 MPa/4800 με/23.4 GPa. Additionally, the stress/strain sensitivity and compressive strength are improved by 29.3 %/43.4 % and 7.9 % ～ 60.2 %, respectively, compared with the single CNTs or GNPs cement-based composites. Therefore, this composite is a potential sensing candidate for smart civil infrastructures.

Synthesis of graphene/Ru/NiO composites as highly active oxygen evolution reaction electrocatalysts

Graphene nanoplates which are decorated uniformly with ruthenium (Ru) and nickel oxide (NiO) nanoparticles, are fabricated via ball milling of graphite, triphenylphosphine ruthenium chlorides and nickel chlorides. Electrochemical measurement results demonstrate that the resultant graphene/Ru/NiO composites deliver a lower overpotential of 240 mV at current density of 10 mA cm−2 and better durability for oxygen evolution reaction (OER) than the state-of-the-art iridium oxide catalysts. The superior OER performances of the graphene/Ru/NiO composites are attributed to collective contributions of Ru and NiO.

Shape-stabilized phase change materials for thermal energy storage and heat dissipation

Shape-stabilized phase change material (SSPCM) are widely used as energy storage materials due to its advantages of easy preparation and adjustable scale. But the thermal conductivity enhancement of SSPCM still need to be further studied to improve the energy storage efficiency. In this work, silicone rubber (SR)/paraffin@SiO2 (Pn@SiO2)/graphene nanoplates (GNPs) shape-stabilized phase change materials (SPG) with different GNPs content were prepared. Pn@SiO2 and GNPs can be homogeneously dispersed in the SR matrix due to the enhanced interfacial compatibility between Pn@SiO2 and SR. The leakage rate of SPG composites was as low as 0.25% due to the protection of SiO2 shell, SR matrix and GNPs. The SPG composites had excellent thermal storage properties, with the enthalpy about 50 J·g−1. The thermal conductivity of SPG composites was improved with the content of GNPs, the thermal conductivity of SPG reach 0.989 W·m−1·K−1 at a GNPs content of 10 phr. The low hardness of SPG composites above the phase change temperature can provide a more cohesive surface when applied to heat dissipation. The heat dissipation of the SPG composites in electric devices was simulated and demonstrated that the addition of GNPs made the heat dissipation rate of the SPG composites increased significantly. Therefore, the SPG composites can be applied in thermal energy storage and heat dissipation of electronic devices.

Vinyl-ester nanocomposites based on a binary-solvent system for well-exfoliated graphene and enhanced performance

This paper introduces a green approach for preparing well-dispersed graphene nanoplates (GNPs) in vinyl-ester (VE) resin. The GNPs were exfoliated in a novel binary-solvent system comprised of a water and ethanol mixture (S nanocomposites). Water and ethanol were considered poor solvents for graphene, but a combination of them could be an ideal solvent mixture. TEM images of the S nanocomposites revealed well-exfoliated graphene sheets with a few wrinkles. Hence, the effective surface areas of the GNPs considerably increased, playing a vital role in enhancing the performance of the nanocomposites. With the incorporation of just 0.4 wt% of exfoliated GNPs (S2 nanocomposite) in the VE, the tensile strength, and toughness enhanced by 51%, and 63%, respectively. Fractography analysis indicated smooth fracture surfaces of pure resin changed to very rough surface structures for the S2 nanocomposite. The viscoelastic properties of the specimens indicated that directly loading GNPs into the resin decreased the glass transition temperature (Tg) of the VE resin. In contrast, the samples prepared by liquid-phase exfoliation enhanced the Tg of the VE. Lastly, the barrier properties of the S2 nanocomposite revealed that its water absorption decreased by 26% compared to the pure resin.

Morphological and functional characterization of electroplated Ni-graphene composite coatings

Composite coatings (CECs) are providing a unique technological advantage for improving mechanical and tribological surface properties. Among different methods, electrodeposition is one of the most exploited to produce composite surface coatings on metal substrates. However, the process parameters affect graphene distribution, coating morphology and performance. This paper investigates how different deposition conditions influence the inclusion of large Graphene nanoplates (GnPs) in a Nickel matrix and the coating morphology and tribological performance. Set the process condition such as electrical parameters and the galvanic bath, the work focuses on the stirring rate effect. To this end, Ni-GnP coatings were obtained by a laboratory setup and evaluated through surface profilometry, SEM characterization and a dry-sliding linear reciprocating wear test. The results highlight the influence of stirring on coating uniformity. The low stirring rate allows larger particles to be embedded, which are not thoroughly covered; however, they act as a solid lubricant and reduce the friction coefficient.

Preparation of high-performance manganese-based pseudocapacitor material by using spent lithium-ion battery anode graphite via mechanochemical pretreatment

The potential for recycling graphitic carbon from lithium-ion battery (LIB) anodes has been overlooked due to its relatively low economic value in applications. This study proposed to use graphene nanoplates (GNPs), which were obtained from spent lithium battery anode graphite, treated with ball-milling method, for hydrothermal synthesis of MnO2-supported graphene nanoplates (MnO2/GNPs) composites materials. The composites exhibited excellent electrochemical characterization curves, indicating ideal capacitance characteristics. The analysis of MG24-20 material showed the good impact resistance and capacity retention around 100% with capacitance of 124.6F/g at 10 mV/s, surpassed similar samples using precious metals and high-end materials, enabling the reuse of spent graphite in energy conversion and storage system for effective utility.Graphical

Synthesis of graphene nanocomposites integrated with 3D bimetallic magnesium/cobalt metal-organic framework as anodic material for solid-state asymmetric supercapacitors

In this study, we have grown 3D porous bimetallic Mg/Co MOF in the presence of exfoliated graphene nanoplates (EGNPs) via a one-step in-situ hydrothermal process, where 1,3,5-benzenetricarboxylic acid (BTC) was used as an effective organic linker since it is cost-effective and EGNPs served as a conductive component. Morphological characterization of Mg/Co-BTC MOF@EGNP nanohybrid confirmed the homogeneous growth of ball-shaped Mg/Co-BTC MOF around the graphene nanoplates, while nitrogen adsorption-desorption analysis revealed large surface area with a high volume fraction of mesopores. This surface features is highly favorable for rapid ion/electron transportation that ensures high specific gravimetric capacitance (838 F/g) and noticeable rate capability (81 % capacitance retention). As-synthesized nanohybrid was used as anode material to construct a prototype all-solid-state asymmetric supercapacitors (ASC) device with a significantly high energy density of 73.82 Wh kg−1, a wide potential window of 0–1.7 V, admirable capacitance retention of 95.1 % after 8000 cycles, and long self-discharge time. Moreover, these capacitance performances also demonstrates the reliability of the as-synthesized poly vinyl alcohol (PVA)-Li2SO4 membrane as a separator-cum-electrolyte for fabrication of future leakage-proof ASCs for wearable electronics. This work can lead to manufacting innovation in the future.

Controlled fabrication of Fe3N@NG composites as superior oxygen evolution reaction electrocatalysts

We report the controlled fabrication of nitrogen doped graphene (NG) nanoplates, which are uniformly decorated with iron nitride (Fe3N) nanoparticles, via ball milling of mixtures of graphite and iron nitrates and the following ammonia annealing. The obtained Fe3N@NG composites demonstrate excellent electrocatalytic activity and durability for oxygen evolution reaction, both of which outperform those of the state-of-the-art iridium oxide catalysts. This may be attributed to nitrogen doping as well as the synergistic effect between Fe3N and graphene nanoplates.

Multiple shearing-induced high alignment in polyethylene/graphene films for enhancing thermal conductivity and solar-thermal conversion performance

The simultaneous achievement of ordered alignment for fillers and polymer matrix is highly desired in polymer-based thermally conductive composites, but it is still extremely challenging. Herein, we put forward a layer-by-layer scraping (LbLS) method to simultaneously arrange ultra-high molecular weight polyethylene (UHPE) chains and graphene nanoplates (GNP) into a highly oriented structure. When UHPE/GNP gel suffering the strong shearing effect during LbLS process, the inner UHPE chains and GNP were dragged and orderly arranged along shearing direction, and these oriented structures were retained after rapidly drying by distillation. After layer-by-layer stacking, nacre-like UHPE/GNP films with tightly layered structure were obtained. By adjusting the scraping gap from 200 to 50 μm, the oriented structure can be effectively reinforced with the Herman orientation factors f increasing from 0.83 to 0.88 for GNP and 0.75 to 0.82 for UHPE chains. The highly ordered structure can form a tight and oriented thermal conduction network with low interfacial thermal resistance in plane. The LbLS composite film thus significantly enhanced the in-plane thermal conductivity up to 28.88 W/mK, compared with traditional solution casting film (9.63 W/mK). Moreover, the highly oriented structure can significantly increase the solar-thermal conversion performance (58.1 °C@100 mW/cm2) by improving its light absorption ability comparing to that of solution casting film. Besides, the mechanical strength and toughness that depend on the filler and chain alignment were effectively increased by the oriented structure.

Analyzing battery thermal management systems: A comparative study of hydrogel and various PCMs in different configurations and convection conditions

No comprehensive analysis has been conducted to compare the performance of hydrogel- and phase change materials (PCMs)-based approaches for cooling lithium-ion batteries in the literature. The present study addresses this gap by comparing the effectiveness of hydrogel and various PCMs in two pack configurations: a fully-filled pack (Pack I) and a partially-filled pack (Pack II) in different convection conditions. While PCM-filled packs show no significant decrease in the cell temperature as a function of the distance between the cells, hydrogel-based cooling results in a significant decrease of 5.27 °C in the maximum temperature of the pack (Tmax) with increasing the distance from the cell radius to twice the cell radius. The study also finds that the effectiveness of latent heat in reducing the cell temperature decreases at higher melting temperatures. Among Packs I with small cell distances, n-Octadecane with the melting temperature of 28°C performs best with Tmax of 45.1 °C at the end of the cycles. However, for large cell distances (twice the cell radius), the hydrogel pack outperforms other cooling methods with a Tmax of 36.1 °C. In Packs II, at all cell distances, n-Octadecane is preferred. For hydrogel, at the end of the cycles, Tmax of Pack I is 3.0°C lower than that of Pack II under natural convection conditions. The study also reveals that Packs II with forced convection conditions are more effective than Packs I. Finally, the research shows that dispersing graphene nano-plates in n-Octadecane has an insignificant effect on the thermal behavior of the battery packs.

Application of single and multi-solid phase STFs to Twaron fabrics: evaluation of energy absorption performances

The present study aims to enhance the energy absorption performance of Twaron aramid fabrics by impregnating them with single and multi-solid phase shear thickening fluids (STFs). To investigate the energy absorption capacity of Twaron 200 and Twaron 460 fabrics, surface friction, yarn tensile, and ballistic tests have been performed. Silicon carbide (SiC), graphene nanoplate (GNP), and carbon nanotube (CNT) are utilized both individually and in hybrid forms to examine the impact of multi-solid phase STFs. The research reveals that STFs reinforced with SiC and GNP exhibit higher viscosity and rheological behavior compared to other hybrid nanoparticles. The addition of SiC and GNP reinforced STF (STF/SiC + GNP) suspension significantly increases the friction coefficient by approximately 82% for Twaron 200 and 120% for Twaron 460 in comparison to neat fabric. Moreover, the maximum yarn tensile strength of Twaron 460 is higher than that of Twaron 200 in both neat and STF impregnated fabrics. The research also states that STF impregnation procedure improves the ballistic performance of neat fabrics in both fabric types. The ballistic test results show an increase in the protective performance of STF impregnated fabrics reinforced with nanoparticles. The best ballistic performance is found in STF/SiC + GNP impregnated fabrics in Twaron 200 and Twaron 460 samples.

High erosion resistance thermoplastic polyurethanes composites fabricated via intercalation reinforced interfacial interaction

AbstractThe weak interface and poor dispersion of carbon nanofillers in polymer matrix composites lead to a significant decrease in their performance, restricting the development of polymer nanocomposites. In this work, a highly facile strategy has been developed to improve the interfacial adhesion performance between graphene nanoplates (GNP) and thermoplastic polyurethanes (TPU) matrix via self‐polymerization of dopamine. Then, single‐walled carbon nanotubes (CNT), as reinforcing agent, were introduced into surface modified GNP solution to prepare the corresponding ternary composites. Scanning electron microscope images show that GNP and CNT formed 3‐D interconnecting network‐like architecture. The sample modified with three layers of nonwoven fabric decorated with 1.0 mg/mL nanomaterial exhibit a tensile strength 35% higher than that of the virgin TPU. Consequently, compared with virgin TPU, the erosion resistance and thermal conductivity are enhanced by 78% and 45%, respectively.

Impact of different surfactants on graphene nanoplates enhanced paraffin-based phase change material

Phase change materials (PCMs) is a unique material that been widely explored for thermal energy storage (TES). PCM nature of low thermal conductivity limits the performance and heat transfer characteristics. Nano-filler been used widely to enhanced PCM thermal conductivity and improved the thermal physical properties. This research work study the nano-filler impact of graphene nano plate (GNP) enhanced paraffin-based PCM with different surfactant (cetryl trimethyl ammonium bromide; CTAB and SDBS) being added. Two step method being applied to fabricate the composites of RG (RT44HC with GNP), RGC (RG with CTAB) and RGS (RG with SDBS) in different weight percentage. The analysis on Fourier transform infrared spectrum shows stable results chemically and physically. The thermal stability shows an improvement as GNP prolong the weight degradation temperature of the composite. An improvement in thermal conductivity to 59.1% achieved as the SDBS surfactant added to RG composite. The addition of GNP and surfactant gives promising results and improvement in RG composite development for TES application in photovoltaic thermal (PVT) system.

A Voltammetric Sensor Based on Carbon Veil Modified with Graphene and Phytosynthesized Cobalt Oxide Nanoparticles for the Determination of Food Dyes Tartrazine (E102) and Allura Red (E129)

A voltammetric sensor based on carbon veil modified with graphene nanoplates and phytosynthesized cobalt oxide Co3O4 nanoparticles is proposed for the determination of tartrazine (E102) and allura red AC (E129). The use of a composite nanomodifier contributes to an increase and better separation of the oxidation currents of azo dyes on their simultaneous presence. The process of the oxidation of azo dyes is irreversible, involves two electrons, and has a mixed nature. The sensor is characterized by a low limit of detection: 30 nM for E102 and 27 nM for E129, and in the inversion mode 16 and 3 nM, respectively. The analytical range the dyes is 0.1–15 µM. The sensor has been successfully used in the analysis of fruit jellies and beverage. The advantages of the developed sensor are high performance and operational characteristics, ease of manufacture, and low cost.