Search Results (371)

Carbon Fiber-Reinforced Polymer (CFRP) composites represent a transformative class of structural materials, combining low density, high specific strength, and excellent fatigue resistance. This review provides a comprehensive overview of CFRPs, addressing their structure, manufacturing routes, mechanical performance, and functional behavior, with particular emphasis on damage tolerance, tribological properties, and environmental durability. The discussion begins with the classification and morphology of carbon fibers, highlighting their influence on composite anisotropy and interlaminar behavior. The effects of impact loading, delamination, and environmental conditioning on residual strength and fatigue life are then examined, with reference to established evaluation methods such as ASTM D7136 and compression-after-impact (CAI) testing. From a tribological perspective, the incorporation of nanoscale additives, such as graphite nanoplatelets and TiO₂ nanoparticles, and their contribution to enhancing wear resistance by promoting the formation of stable tribofilms, is explored. Advances in processing techniques, including low-pressure curing and improved resin systems, are also discussed for their roles in enhancing manufacturability and energy efficiency. Overall, the review underscores that optimal CFRP performance is achieved through the synergistic integration of fiber architecture, matrix design, and precise processing control, while future progress in nanomodification, recycling, and sustainable curing technologies is expected to further expand CFRP applications in the aerospace, automotive, and high-performance engineering sectors. Full article

Thermal storage tanks offer significant potential for addressing the performance degradation and supply–demand mismatch of air-source heat pump (ASHP) systems in cold regions. This study employs a combined numerical and experimental approach to systematically investigate the impacts of fin structure, composite phase change material (CPCM) composition, and inlet temperature on the performance of shell-and-tube storage units. Results indicate that natural convection is the dominant heat transfer mechanism, and the incorporation of expanded graphite (EG) substantially enhances the thermal conductivity of the PCM. A critical finding is the identification of an optimal finning coefficient range (4.16 to 5.68) that maximizes enhancement performance. A validated numerical model (error < 5%) and a predictive formula for melting time were developed. Experimental data show that the optimized finned structure reduces PCM melting time by 47% to 59%. This research provides theoretical and practical tools for designing high-efficiency thermal storage, supporting the development of flexible and integrated building energy systems. Full article

Graphite is a critical mineral used to produce anodes for lithium-ion batteries (LIBs). Battery-grade anode active material (AAM) is derived from natural graphite. As the electric vehicle (EV) market continues to expand across North America, establishing a local AAM supply chain has become increasingly important. This new supply chain must be sustainable if critical minerals are to replace the internal combustion engine (ICE) powertrain in vehicles. Canada possesses abundant critical mineral resources, including natural graphite, which is mined and processed in the province of Québec. To better understand the environmental implications of this emerging supply chain, a life cycle assessment (LCA) was conducted on a Québec-based graphite mine and processing facility. The results showed that producing one ton of AAM in Québec generates approximately 1.44 tons of CO₂-equivalent (long-term) emissions, significantly lower than the 9.6 tons of CO₂ emitted per ton of graphite produced in China. Natural gas used for purification and coating at the process plant was the largest contributor of CO₂ in this study. Although this LCA in Québec represents a substantial reduction in carbon intensity, further opportunities must be explored to enhance sustainability and strengthen North America’s graphite supply chain. Full article

Wood, which is flammable, is commonly used as a building material and can be improved using a suitable surface treatment. A promising coating solution is polyurea, featuring properties like flexibility, mechanical resistance, resistance against water, etc., but it is also easily flammable. Expandable graphite (EG) is effective as a flame retardant and environmentally suitable. In this study, we studied the suitability of polyurea improved with EG. Spruce wood samples with dimensions of 50 mm × 40 mm × 10 mm were divided into eight groups, each including five samples. Each group was subjected to two applications of polyurea and EG in various combinations to examine the best combination with the lowest mass loss. The second component of the experiments aimed to examine the effectiveness of EG, which was applied in different weights. During the experiments, samples were thermally loaded in an apparatus for 10 min, where a heat flux of 30 kW·m⁻² was applied to the sample surface and the mass loss was continuously recorded. Lastly, thermal analysis was performed. The best results were observed for the combination of NEOPROOF mixed with 0.3 g of EG covered with NEODUR. The thermal analysis results revealed substantial differences: NEOPROOF, a polyurea, had only one degradation step, while NEODUR, which also contained polyurethanes, decomposed in several steps. Full article

The coexistence of Cu in copper sulfate electrolyte significantly affects the microstructure and performance of the copper foil. So far, there has been little quantitative analysis of Cu⁺ in the electrolyte during the copper foil production process. This paper fabricated a 2,2′-Biquinoline (BIQ) modified expanded graphite (EG) electrode electrochemical sensor for the selective determination of Cu⁺. EG, with its large specific surface area and excellent adsorption and electrochemical properties, significantly enhances analytical sensitivity. Additionally, BIQ’s specific coordination with Cu⁺ improves the sensor’s rapid and effective quantification of Cu⁺ in the electrolytic copper foil electrolyte. The linear equation of this sensor is I = 0.03769 + 0.29997 × c (R² = 0.9989), with a detection limit of 8 μg/L (S/N = 3). The BIQ-modified EG electrode has good selectivity for Cu⁺, with a recovery rate for cuprous ions of 101.00% to 105.00% under the coexistence of 10,000 times Cu²⁺, and an RSD of less than 2%. This sensor’s efficient, sensitive, and selective detection of Cu⁺ can be an effective method to improve the quality of electrolytic copper foil products. Full article

Phase change materials (PCMs) have emerged as an innovative solution in thermal energy storage and thermal management systems (TMS) owing to their outstanding latent heat of fusion during the phase change process. This study is especially addressed to the battery TMS based on Organic PCMs for fast charging/discharging applications of lithium-ion batteries (LIBs). These fast processes generate excessive heat during operation, degrade battery performance, decrease energy efficiency, and reduce the lifespan and safety of batteries. Organic PCMs exhibit desirable properties, including high latent heat capacity, good thermal characteristics, low cost, and ease of integration. The major challenge for the successful application of organic PCM comprises its low thermal conductivity, which impacts the heat storage and release rates. PCM-based Paraffin Wax (PW) has been designed by including expanded graphite (EG) as a high thermal conductivity additive in high latent heat of paraffin wax. Experiments focused on the effects of heating methods (microwaves/S-type EG composition and conventional electric oven/S′-type EG composition) of expandable graphite on the thermophysical properties of different PW/EG composites. The crystal and chemical structure of the study samples were analyzed by X-ray diffraction and Fourier-Transform Infrared spectroscopy. The battery module created with PW/EG composites were ample examined using charging/discharging experiments at five different C-rates. The effect of current rates on battery surface temperature is investigated in two cases: with PCM cooling and with air cooling. A 20.43% decrease in battery temperature is found at 5C rate with PCM cooling and a maximum reduction in battery charging time of 43.77%. Full article

With the expanding electric vehicle market, there is increasing demand for improved battery safety and fast-charging performance. Ceramic-based solid electrolytes have attracted attention due to their high thermal and electrochemical stabilities. Li-glass solid electrolytes (e.g., Li₂O–LiCl–B₂O₃–Al₂O₃, LCBA) are promising materials because they enable low-temperature sintering (<550 °C), suppress lithium volatilization, mitigate ionic conductivity degradation, and enable cost-effective manufacturing. LCBA can be co-sintered with graphite anodes to form composite anode materials for LCBA-based all-solid-state batteries. However, insufficient densification and shrinkage mismatch often lead to limited ionic conductivity and interfacial delamination. In this study, the sintering behavior of LCBA was investigated using a hot-press-assisted process, and LCBA/graphite composite anodes were co-sintered to evaluate their electrochemical and interfacial properties. The LCBA electrolyte sintered at 550 °C exhibited high densification and an ionic conductivity of 3.86 × 10⁻⁵ S cm⁻¹. Additionally, the composite containing 50 wt% LCBA achieved a maximum tensile stress of ~0.23 MPa and a high interfacial fracture energy of ~180–200 J m⁻², indicating enhanced deformation tolerance and fracture resistance. This approach improves the densification, ionic conductivity, and interfacial mechanical stability of LCBA solid electrolytes and their composite anodes, highlighting their potential for next-generation all-solid-state secondary battery applications. Full article

Hard carbon is widely recognized as a viable anode candidate for sodium-ion batteries (SIBs) owing to its electrochemical advantages, yet simultaneously enhancing specific capacity and rate capability, arising from insufficient plateau capacity, remains a long-standing challenge. Herein, we present a strategy for fabricating ZnCl₂-modified hard carbon (HCMZ-X) using waste macadamia shells and ZnCl₂ as a multifunctional structural modifier through a facile high-temperature carbonization. This approach effectively expands the graphite interlayer spacing to 0.394 nm, reduces microcrystalline size, and induces abundant closed pores, synergistically improving sodium-ion storage kinetics within the hard carbon framework. Mechanistic investigations confirm an “adsorption-intercalation-filling” storage mechanism. Hence, the optimized HCMZ-3 delivers a high reversible capacity of 382.05 mAh g⁻¹ at 0.05 A g⁻¹, with the plateau region contributing approximately 70%, significantly outperforming that of unmodified hard carbon (262.64 mAh g⁻¹). Remarkably, it achieves stable rate performance, delivering 190 mAh g⁻¹ at 1 A g⁻¹, along with excellent cycling stability, retaining over 90% after 500 cycles. By rational pore-structure modulation rather than excessive surface activation, this cost-effective method utilizing agricultural waste and ZnCl₂ dual-functional modification partially alleviates the intrinsic energy-density limitation of hard carbon anodes, advancing the development of high-performance, eco-friendly anodes for scalable energy storage systems. Full article

Organic phase change materials show potential for thermal energy storage, but their scalable implementation is limited by fixed phase change temperatures, molten leakage, and low thermal conductivity. To address the temperature constraint, a binary eutectic system of 1-tetradecanol and 1,10-decanediol is prepared, expanding the operational temperature range for building thermal management. Compositing the eutectic with expanded graphite yields a composite material that exhibits a low leakage and a markedly improved thermal conductivity of 4.642 W/(m·K), which is approximately 12 times that of the pure eutectic. The composite maintains distinct phase transition properties, with melting and solidification temperatures of 37.77 °C and 29.38 °C and corresponding latent heats of 218.80 J/g and 216.66 J/g. It also demonstrates a good cycling stability, retaining over 87% of the original latent heat after 2000 thermal cycles. While these findings remain valid under controlled conditions, further studies are required to evaluate their practical feasibility and long-term durability in real-world scenarios. This work establishes a systematic approach for fabricating composite phase change materials and provides a promising candidate for building thermal management applications. Full article

In the article we investigated the effectiveness of a synergistic system designed to reduce the fire hazard of flexible polyurethane (PUR) foams. The examined system consisted of a carbon-based filler graphene (G), carbon nanotubes (CNTs), or expanded graphite (EG) combined with melamine polyphosphate (MPP). The investigated polyurethane foams (PUR) were synthesized at room temperature via a polycondensation reaction between a polyol and an isocyanate, with an OH: NCO molar ratio of 2:1. Both the carbon fillers and melamine polyphosphate were homogeneously dispersed within the polyol component. Thermogravimetric analysis (TGA), cone calorimetry, and microcalorimetry were used to evaluate the influence of the fillers on the thermal stability and flammability of the PUR foams. The toxicity of the gaseous products was assessed using a coupled TG-gas analysis system, while the optical density of the evolved gases was determined using a Smoke Density Chamber (SDC). The obtained results demonstrated that the applied synergistic carbon-phosphorus filler system significantly reduced the fire hazard of the tested PUR foams. In particular, the EG5-MPP system enabled the formation of self-extinguishing materials. Full article

This study presents the development of high-performance polymer composites designed for operation under extreme conditions. The research aimed to investigate the influence of laser ablation parameters on the synthesis of carbon nanotubes (CNTs) and to evaluate their efficacy as electrically conductive fillers. CNTs were synthesized using a 200 W laser ablation setup, with the graphite-to-ferrocene ratio in the target varied from 3:1 to 8:1 at a constant pulse duration of 0.1 s. Comprehensive analysis by Raman spectroscopy and scanning electron microscopy (SEM) demonstrated that this method enables the production of nanotubes with controlled morphology and diameters ranging from 20 to 70 nm. It was established that varying the target composition serves as an effective tool for managing the specific surface area and structure of the synthesized CNTs. The obtained nanotubes exhibited high efficiency in forming conductive networks within polymer matrices (exemplified by silicone), thereby imparting the composites with tailored electrophysical properties. A key finding of the work is the identified dependence of the positive temperature coefficient of resistance (PTCR) of the composites on the morphology and composition of the carbon filler. This property opens prospects for creating “smart” self-regulating heating elements based on the developed materials, including for anti-icing systems. Thus, the study results confirm that the targeted synthesis of CNTs via laser ablation and their subsequent incorporation into polymer matrices constitutes an effective strategy for expanding the functional capabilities of composite materials in modern technical applications. Full article

Mesoporous carbons based on silica hard templates were used to investigate physical processes in confined pores. Nitrogen adsorption, scanning electron microscopy, and scattered X-ray analyses revealed two classes of materials: carbons with moderate and highly developed mesoporosity. The pore structure was strongly dependent on pore expanders which proved essential for generating open, accessible architectures. All carbons exhibited a basic, graphitic surface (pH_PZC = 8.4–10.9), enriched in electron-donating oxygen functionalities. Differential scanning calorimetry studies of confined water showed that melting point depression follows the Gibbs–Thomson relationship, confirming the strong dependence of phase transitions on pore size and water–surface interactions. Adsorption experiments using methylene blue demonstrated that capacity is governed by surface area, pore volume, and pore size distribution. For carbon with the largest average pore size, adsorption of various dyes revealed that uptake decreases with increasing molecular size, whereas affinity depends strongly on electrostatic interactions. Kinetic studies indicated that carbons with larger mesopores exhibit the fastest adsorption, and that large, complex dye molecules undergo significant diffusion limitations. Overall, the results show that the interplay between pore structure, adsorbate size, and surface chemistry influences both the equilibrium uptake and adsorption kinetics in mesoporous carbon materials. Full article

The large-scale integration of renewable energy systems requires hydrogen storage technologies that can decouple energy production from energy utilization and allow for seasonal storage. Metal hydrides can offer higher volumetric energy density and operational safety than compressed H₂ but are limited by heat-transfer constraints that slow hydrogen absorption and desorption. This work investigates the performance of metal hydride–phase-change material hydrogen storage systems through advanced numerical modeling. Five reactor geometries are evaluated to quantify how longitudinal fins, transversal fins, helical fin structures, and graphite-enhanced composites influence heat removal, charge/discharge rates, and overall power density. Results show that longitudinal and transversal fins accelerate hydrogen absorption and desorption, reducing cycle times by up to 80.6%. The optimized finned helix configuration achieves the highest performance, with a power density of 2.55 kW/kg and charge/discharge powers of 6.75 kW and 13.25 kW, respectively. Expanded graphite further enhances kinetics in low-Biot-number designs, reducing cycle times by more than 30%. These findings provide design guidelines to maximize performance and efficiency of solid-state hydrogen storage for medium- and high-power applications. Full article

This study investigated the synergistic mechanisms of flame retardancy and smoke suppression exhibited by a novel ternary additive in warm-mix asphalt (WMA). The ternary additive consisted of aluminum hydroxide (ATH), organic montmorillonite (OMMT), and expandable graphite (EG). A comprehensive experimental program was conducted, encompassing limiting oxygen index (LOI) testing, cone calorimeter testing, thermogravimetric analysis (TGA), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS). The results showed that incorporation of 6 wt% of the ternary additive (by mass of the asphalt binder) markedly improved the fire resistance of the WMA. The LOI increased from 19.8% (neat asphalt) to 25.2%. Cone calorimeter tests revealed a 23.9% increase in time to ignition, a 24.2% reduction in peak heat release rate, and a 47.5% decrease in total smoke production. These improvements are attributed to a synergistic mechanism involving the endothermic decomposition of ATH, the char-promoting effect of OMMT, and the intumescent expansion of expandable graphite (EG) forming a compact insulating barrier, which collectively inhibit combustion and smoke release. The ternary additive exhibits considerable promise as an effective flame-retardant modifier for enhancing the fire safety of warm-mix asphalt pavements, especially in high-risk scenarios such as tunnels. Full article

The structural modification of tyre-derived activated carbon (TDAC) after chemical activation is not sufficiently recognised yet, especially regarding its crystallinity and porosity. This study examined the development of the crystal structure of TDAC by X-ray diffraction (XRD) analysis, concentrating on critical parameters like interplanar distance (d(002)), crystallite size (Lc), and crystalline percentage. Mixed tyres were pyrolysed at 550 °C to produce char and then chemically activated with KOH at different ratios and temperatures, thereafter undergoing structural characterisation. The results indicate that TDAC is mostly non-graphitizing, maintaining a disordered turbostratic structure even after activation. The widening of the (002) XRD peak and the lack of distinct (hkl) diffraction peaks validate its amorphous characteristics. Higher activation levels lead to an expanded surface area with decreasing crystallite size, signifying a shift towards higher disorder. This research examined the relationship among activation factors, porosity, and structural alterations, emphasising the compromise between crystallinity and surface area. Full article