Eutectic Composites Research Articles

Unveiling exotic multi-scale microstructure transformation and crack formation mechanisms in eutectic ceramic composite by laser powder bed fusion

Laser powder bed fusion (LPBF) represents an advanced and versatile technology. Exploiting its distinctive advantages for direct and rapid fabrication of complex-structured melt-grown oxide eutectic ceramic composite represents a pioneering yet challenging endeavor. In this work, LPBF is creatively employed to fabricate turbine blade-shaped, in-situ ternary eutectic ceramic composite. Through the integration of experimental procedures, Finite element method (FEM) simulations, and numerical analyses, an innovative design and manufacturing of oxide eutectic ceramic composites have been successfully established. Comprehensive FEM simulations, with detailed interface characteristic analysis, have revealed macro-scale cracks induced by intense maximum principal stress, and micro-cracks stemming from significant interfacial energy disparities among the three constituent phases. The applications of rapid solidification and nucleation theories have facilitated profound insights into the formation mechanisms of multi-scale exotic microstructures, including top-layer coarse dendrites, rosette-like spherical internally grown eutectic colony within layers, and columnar eutectic colonies with ultra-fine lamellar eutectic structures. Micro-mechanical property testing reveals enhanced performance in the inter-layer ultra-fine lamellar eutectic structure, which is attributed to a refined eutectic spacing of approximately 61 nm, coupled with distinct and robust bonding interfaces. These groundbreaking achievements, focusing on the processing-microstructure-property relationship in the fabrication of gas turbine blade-shaped solidified eutectic ceramic composite using LPBF, provide invaluable theoretical insights and data. This knowledge is crucial for the LPBF production of high-temperature structural materials, highlighting its significant potential applications in fields of aerospace and mechanical engineering.

Unlocking interfacial effects in NiTiO3-TiO2 eutectic composite: Enhancing overall electrocatalytic and photoelectrochemical water splitting

This study introduces a novel approach to tackle the urgent demand for catalysts possessing both bifunctional capabilities and efficient photocatalytic properties. By employing the micro-pulling down method, a NiTiO3/TiO2 eutectic composite is synthesized, creating an interface rich structure. This composite is utilized as a photo-anode, displaying a significant photocurrent of 3.5 mA/cm2 at 1.4 V. Through annealing in an H2 atmosphere, the catalytic performance is finely adjusted, revealing distinct electrochemical activities at the interface of NiTiO3 and TiO2. Enhanced interfacial adsorption is confirmed by scanning electrochemical microscopy post-annealing. Remarkably, the annealed NiTiO3/TiO2 exhibits outstanding overall water-splitting efficiency, with minimal overpotentials of 80 mV (at 10 mA/cm2) and 120 mV (at 50 mA/cm2) for the HER and OER, respectively. The low Tafel slope (41 mV dec-1) underscores rapid water splitting kinetics. Density functional theory (DFT) calculations suggest that NiTiO3-TiO2 heterostructure can enhanced the catalytic properties of the surface providing higher adsorption of the electrolyte ions during catalytic reactions. This study establishes a straightforward crystal growth strategy for the design of highly effective, enduring, and bifunctional photocatalytic catalysts, signaling promising advancements in water splitting technology.

Nanoconfinement of an ammine magnesium borohydride composite electrolyte in a mesoporous silica scaffold

Improvements of magnesium ionic conducting materials are important for the development of novel magnesium solid-state batteries. Here we investigate the effect of nanoconfinement of one of the most conductive magnesium electrolytes − the (Mg(BH4)2·NH3)x(Mg(BH4)2·2NH3)1−x composite. The synthesis of nanoconfined Mg(BH4)2·1.47NH3 in a mesoporous silica scaffold (SBA-15, pore size 5.8 nm) is achieved through melt infiltration. Various degrees of pore filling are investigated, ranging from 100 to 300 %. Solid-state 11B nuclear magnetic resonance analysis confirms the successful stabilization of the highly dynamic eutectic molten state of Mg(BH4)2·1.47NH3 through nanoconfinement. The confined sample exhibits notable thermal stability, maintaining integrity up to approximately 100 °C, and the eutectic molten composite does not recrystallize within five months after synthesis, upon storing at room temperature. Notably, among the confined samples, 200 % pore filling displays promising Mg2+ ionic conductivity within the range of 9.1 × 10−6 to 2.7 × 10−4 S cm−1 and a low activation energy of 0.69 eV at temperatures from 32 to 80 °C. Furthermore, the compound was found to have a low electronic conductivity of 7.93 × 10−11 S cm−1 at 70 °C resulting in an ionic transport number close to unity.

Experimental study on supercooling performance optimization of sodium acetate trihydrate phase change energy storage materials

In response to the pressing demands for sustainable energy, the development of efficient energy storage materials and technologies has emerged as a focal point in contemporary research. Sodium acetate trihydrate (CH3COONa·3H2O, SAT), recognized for its potential as a mid-to-low temperature phase change material (PCM) in energy storage systems, encounters significant limitations due to its substantial supercooling effect and inferior thermal conductivity. Traditional approaches to enhance SAT's thermal performance often involve costly additives, which hinder their adoption on an industrial scale. This study introduces SAT as a base compound, and through a fusion blending method, binary eutectic hydrate salt composites (CPCMs) are synthesized with either sodium sulfate decahydrate (Na2SO4·10H2O, SSD) or disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O, DHPD) in varying ratios. The results demonstrate that the prepared eutectic hydrates effectively reduce the supercooling degree of pure SAT from above 35 °C to below 10 °C, with the SAT/SSD-5/5 composition exhibiting the lowest supercooling at 3.17 °C. Notably, these eutectic blends possess appreciable latent heat capacities, with SAT/SSD-9/1 delivering 196.18 J/g, and exhibit improved thermal conductivity, as seen in SAT/SSD-3/7 with a coefficient of 0.8925 W/(m·K). Furthermore, the SAT-based eutectic hydrates are devoid of expensive additives, facile to manufacture, and applicable over a broad temperature range (20–60 °C), making them highly suitable for large-scale commercial applications.

High-sensitivity humidity sensor based on Poly(vinylidene fluoride)/Deep eutectic solvent composites

This study explores the incorporation of deep eutectic solvent (DES) into a poly (vinylidene fluoride) (PVDF) matrix to fabricate PVDF/DES composite thin films. Subsequently, electrodes were screen-printed onto the thin films to create PVDF/DES humidity sensors. The investigation delved into the crystalline structure of PVDF, the cross-sectional morphology and electrochemical property of PVDF/DES composite films, and the humidity sensing response of PVDF/DES humidity sensors. The study revealed that adding DES leads to the formation of porous composite films with electrical active phases and high electrical conductivity. The sensitivity of the PVDF/DES humidity sensor increases with the content of DES. This work provides a novel method for the fabrication of humidity sensors, holding significant potential in various applications such as respiratory monitoring.

Fabrication and performance characterization of Sb2Se3-GaSe eutectic systems

Sb2Se3-GaSe eutectic composites were synthesized by the vertical Bridgman method. XRD analysis and structural study of the Sb2Se3-GaSe eutectics showed that Sb2Se3 inclusions were uniformly distributed in the GaSe matrice. Three eutectic points in the Sb2Se3-GaSe system were studied. The compositions of the three eutectics of 80, 55 and 40 wt.% Sb2Se3 formed in the Sb2Se3-GaSe systems, and the corresponding melting points of 776, 725 and 698 K were determined. Anisotropy of the electrical properties of the eutectic systems was observed. The anisotropy degree was ~103 depending on the crystallization direction.

Predicting rapid growth behavior in solidified eutectic ceramic composites using infrared thermal imaging and thermal field simulation during laser directed energy deposition

Cylindrical Al2O3/GdAlO3 binary in situ oxide eutectic ceramic composite, with a glossy surface and high relative density, has been fabricated using the laser directed energy deposition method (LDED) with optimized process parameters. In a novel and innovative approach, infrared thermal imaging and the finite element method (FEM) have been combined for the first time to capture the temperature field distribution across different regions of the molten pool during the LDED processing of the binary oxide eutectic ceramic composite, thereby synergistically obtaining the solidification characteristics. With an increase in the scanning rate, the temperature gradient within the molten pool decreases from 3.38 × 105 K/m to 1.62 × 105 K/m, while it shows minimal variation with fluctuations of the laser power. Under the conditions of high temperature gradients and rapid non-equilibrium solidification characteristic of LDED, the Al2O3/GdAlO3 (GAP) binary eutectic ceramic composites, which exhibit typical high melting entropy and faceted/non-faceted growth modes, exhibit complex and variable microstructure morphology. A combination of regular/irregular models, including JH (Jackson-Hunt), MK (Magnin-Kurz), GK (Guzik-Kopyciński) and TMK (Trivedi-Magnin-Kurz), is employed to investigate and predict the growth and transformation of microstructures. The JH and TMK models fairly predict the rod-like regular eutectic microstructure inside the colony and lamellar regular eutectic within adjacent layers, respectively. The “Chinese-script” irregular microstructure at the interface between the colony and the layers is consistent with the MK and GK models. The as-deposited eutectic ceramic composite presents ultra-fine microstructures, clear and strongly bonded phase interfaces with low strain energy, contributing to its microstructure stability after high temperature heat treatment at 1773 K for 200 h, and achieving a minimum microstructure coarsening rate of 0.0005 μm/h.

Insight into TaSi2 Nanostructures with Different Morphologies and Their Field Emission Properties

AbstractRecognizing the strong potential of cold cathodes for important commercial applications in fields such as electronics, there is a growing interest in the exploration of novel 1D nanomaterials. Among various cold cathode materials, TaSi2 is of great interest for its outstanding field emission performance. In this work, the Si‐TaSi2 eutectic composite with nano‐sized highly oriented TaSi2 fibers and semi‐coherent phase interfaces is prepared by the laser floating zone melting technique with a very high‐temperature gradient of 6000 K cm−1 at a solidification rate of 200 µm s−1. On the basis of directionally solidified Si‐TaSi2 eutectic composite, well‐aligned TaSi2 nanorod and nanotip arrays are fabricated by inductively coupling plasma (ICP) etching process and HNO3/HF wet etching process, respectively. The field emission measurements show that the field enhancement factor, turn‐on electric field, and effective work function are strongly affected by tip morphologies. The TaSi2 array with regular nanotip structure possesses the best field emission characteristic among all TaSi2 nanostructures, with a relatively low turn‐on field of 4.8 V µm−1 and a high current density of 733 µA cm−2. These findings preliminarily establish a clear relationship between the performance and structure of the array, providing technical guidance for the application of this material in electronic devices.

Enhanced 3D printing and crack control in melt-grown eutectic ceramic composites with high-entropy alloy doping

As a 3D printing method, laser powder bed fusion (LPBF) technology has been extensively proven to offer significant advantages in fabricating complex structured specimens, achieving ultra-fine microstructures, and enhancing performances. In the domain of manufacturing melt-grown oxide ceramics, it encounters substantial challenges in suppressing crack defects during the rapid solidification process. The strategic integration of high entropy alloys (HEA), leveraging the significant ductility and toughness into ceramic powders represents a major innovation in overcoming the obstacles. The ingenious doping of HEA particles preserves the eutectic microstructures of the Al2O3/GdAlO3(GAP)/ZrO2 ceramic composite. The high damage tolerance of the HEA alloy under high strain rates enables the absorption of crack energy and alleviation of internal stresses during LPBF, effectively reducing crack initiation and growth. Due to increased curvature forces and intense Marangoni convection at the top of the molt pool, particle collision intensifies, leading to the tendency of HEA particles to agglomerate at the upper part of the molt pool. However, this phenomenon can be effectively alleviated in the remelting process of subsequent layer deposition. Furthermore, a portion of the HEA particles partially dissolves and sinks into the molten pool, acting as heterogeneous nucleation particles, inducing the formation of equiaxed eutectic and leading primary phase nucleation. Some HEA particles diffuse into the lamellar ternary eutectic structures, further promoting the refinement of eutectic microstructures due to increased undercooling. The innovative doping of HEA particles has effectively facilitated the fabrication of turbine-structured, conical, and cylindrical ternary eutectic ceramic composite specimens with diameters of about 70 mm, demonstrating significant developmental potential in the field of ceramic composite manufacturing.

Compressive Property and Toughening Mechanism of Directionally Solidified Fe(Al, Ta)/Fe2Ta (Al) Eutectic Composites

Herein, Fe(Al, Ta)/Fe2Ta(Al) eutectic composites are prepared using the electron beam floating zone melting directional solidification technique. The compression and fracture toughness properties of Fe(Al, Ta)/Fe2Ta(Al) eutectic composites at different solidification rates are studied with compression and three‐point bending experiments. The toughening mechanism of the material is also analyzed from morphology, composition, and microstructure. The results show that the yield strength and compression properties of the Fe(Al, Ta)/Fe2Ta(Al) eutectic composite are increased with the increase of the solidification rate. The room‐temperature fracture toughness reaches 30.5 MPa m1/2 when the solidification rate is 4 mm min−1. In addition, the material exhibits high strength performance at room temperature. However, it exhibits poor strength and excellent plasticity due to the softening effect of recrystallization at 600 °C. The toughening mechanism of the Fe(Al, Ta)/Fe2Ta(Al) eutectic composites can be summarized as crack blunting, crack branching, crack deflection, and local deformation.

Eutectic phase change composites with MXene nanoparticles for enhanced photothermal absorption and conversion capacity

Phase change composite materials with uniform nanomaterial dispersion are potential solutions for improving thermophysical properties and enhancing latent heat capacity applicable in thermal management. In this study, various transitional carbide-based MXene samples were synthesised via acid etching to augment the heat transfer capacity and efficiency of the solar thermal energy storage (TES). These samples were then uniformly dispersed in a eutectic mixture (1:1) of paraffin wax (PW) and polyethylene glycol (PEG-6000), resulting in the formation of a MePCM composite. The controllable porous structure and hydrogen interactions with the external layer of MXene and long-chain PCM benefitted in the well impregnation of PCM and compatibility impregnated into the composite. An exceptionally higher mass fraction of 1 wt % Ti3C2Tx MXene-based phase change composite unveiled a higher phase change enthalpy of 138.66 J/g in the melting phase and 139.54 J/g in the solidification phase with 89.82 % energy storage efficiency. In contrast to pure eutectic PCM (0.2593 W/mK), the thermal conductivity of MePCM composite is relatively higher and provides a thermal conductivity of 0.9209 W/mK for Ti3C2Tx MXene-based composite. The enhancement of thermal conductivity is ascribed to the increased heat conduction pathway facilitated by the MXene arrangement. The utilisation of spatially constrained eutectic phase change material (PCM) assembly resulted in the development of MePCM, which exhibited enhanced thermal conductivity, chemical and physical stability, and thermal consistency across 500 melting-solidification cycles. Benefitting from the thermal conduction path, the MePCM exhibits an excellent photothermal conversion efficiency of 98.53 %. The thermal responsive tests of Ti3C2Tx and V2CTx MXene composite samples provide better thermal response than eutectic PCM without thermal reduction. With a higher thermal storage capacity and higher heat transfer property, thermally reliable MePCM composites exhibited tremendous potential for photothermal applications.

Insight into faceted-nonfaceted transition of directionally solidified eutectic ceramic composites by laser floating zone melting and infrared imaging

Faceted-nonfaceted transition was found during directional solidification of an Al2O3/Y3Al5O12(YAG)/ZrO2 eutectic ceramic composite at the pulling rate over 260 μm/s by laser floating zone melting. This transition, for the first time, optimized the colony structure of faceted eutectic composite materials, resulting in a refined and homogeneous microstructure consisting of both rod and lamella. Infrared imaging was employed to uncover temperature field evolution of the melt during the transition relying on an interesting measurement calibration strategy. In addition to an in-depth discussion about this evolution, we revealed that the transition was triggered by a critical undercooling at the solid-liquid interface. A 3D model of this novel eutectic structure was established, by which the mechanism of structural optimization achieved by the transition was discussed. We supposed that the growth orientation with the smallest index could firstly occur faceted-nonfaceted transition under a certain undercooling degree, and subsequently predominated the growth of faceted eutectic composite, which contributed to the optimization of faceted eutectic colony structure.

In-situ observation of Ni-11.5 wt%Si eutectic microstructure evolution and exploration of strengthening mode of Ni-Ni3Si eutectic composites

Microstructure evolution of the Ni-11.5 wt%Si eutectic alloy during the melting and cooling process was elaborately examined using a high-temperature confocal laser scanning microscope (HT-CLSM). The thermal stability of the phase composition within the Ni-11.5 wt%Si eutectic alloy was thoroughly analyzed. The intricate mechanism governing the solidification of the Ni-11.5 wt%Si eutectic alloy, along with the formation of the metastable Ni31Si12 phase under varying cooling rates, was systematically investigated. Through in-depth in-situ observations, a well-defined heat treatment procedure was developed for Ni-Ni3Si eutectic composites. Remarkably, the metastable Ni31Si12 phase can completely transform into Ni3Si upon undergoing the prescribed heat treatment, yielding a refined lamellar structure. This structural refinement notably results in substantial enhancements in the compressive properties and fracture toughness of the Ni-Ni3Si eutectic composite at ambient temperatures.

Jet-Printable, Low-Melting-Temperature Ga-xSn Eutectic Composites: Application in All-Solid-State Batteries.

Low-melting-point Ga-xSn eutectic composites and natural silicate mineral powders were used as the electrode and solid-state electrolyte, respectively, in all-solid-state batteries for green energy storage systems. The influences of the Sn content in the Ga-xSn composite electrode on the electrochemical performance of the batteries were evaluated, and liquid composites with a Sn concentration of up to 30 wt.% demonstrated suitability for electrode fabrication through dip coating. Sodium-enriched silicate was synthesized to serve as the solid-state electrolyte membrane because of the abundance of water molecules in its interlayer structure, enabling ion exchange. The battery capacity increased with the Sn content of the Ga-xSn anode. The formation of intermetallic compounds and oxides (CuGa2, Ga2O3, Cu6Sn5, and SnO2) resulted in a high charge-discharge capacity and stability. The Ga-Sn composite electrode for all-solid-state batteries exhibits a satisfiable capacity and stability and shows potential for jet-printed electrode applications.

Stability of crystallographic texture and mechanical anisotropy toward Al2O3/YAG eutectic ceramic composite using single crystalline seeds

During the directional solidification of Al2O3-based eutectic ceramic composites, crystallographic orientation control is a promising method for tailoring the performances of composite parts. However, despite its importance in the fabrication of texture-controlled structural parts, the stable growth of the eutectic crystallographic texture for long distance (growth distance from 30 mm to 120 mm) in ceramic composite system is not widely understood. Herein, the competition and stability of crystallographic texture for Al2O3/YAG eutectic ceramic composite induced by different seeds using the Czochralski (CZ) technique were investigated. When the eutectic composites induced by different single crystalline Al2O3 seeds, coarse Al2O3 particles and uniform eutectic structure appeared alternately below the seeds. While the eutectic ceramic composite induced by YAG seed has a memory effect on the stability of its microstructure and morphology. We demonstrated that the eutectic ceramic composites induced by the ⟨112‾0⟩ Al2O3 and ⟨101‾0⟩ Al2O3 seeds could stably inherit the seed orientation and grow as a single crystallographic texture with a low interfacial strain (<10 %). In particular, the stable evolution of crystallographic texture depended not only on the type of seeds but also on the mutual constraint of eutectic coupling growth. Furthermore, the nano-hardness, elastic modulus, and compressive strength (1600 °C) of the composites induced by different seeds have anisotropic characteristics. However, the bending strength was not sensitive to the change of crystallographic texture. It could maintain excellent high temperature stability, which was approximately 265–316 MPa from room temperature to 1600 °C. These results promote the development of high-performance Al2O3-based eutectic ceramic composites with anisotropic design using seeding technique to tailor their crystallographic texture.

Effect of α″-Ti Martensitic Phase Formation on Plasticity in Ti-Fe-Sn Ultrafine Eutectic Composites.

Extensive research has been conducted on Ti-Fe-Sn ultrafine eutectic composites due to their high yield strength, compared to conventional microcrystalline alloys. The unique microstructure of ultrafine eutectic composites, which consists of the ultrafine-grained lamella matrix with the formation of primary dendrites, leads to high strength and desirable plasticity. A lamellar structure is known for its high strength with limited plasticity, owing to its interface-strengthening effect. Thus, extensive efforts have been conducted to induce the lamellar structure and control the volume fraction of primary dendrites to enhance plasticity by tailoring the compositions. In this study, however, it was found that not only the volume fraction of primary dendrites but also the morphology of dendrites constitute key factors in inducing excellent ductility. We selected three compositions of Ti-Fe-Sn ultrafine eutectic composites, considering the distinct volume fractions and morphologies of β-Ti dendrites based on the Ti-Fe-Sn ternary phase diagram. As these compositions approach quasi-peritectic reaction points, the α″-Ti martensitic phase forms within the primary β-Ti dendrites due to under-cooling effects. This pre-formation of the α″-Ti martensitic phase effectively governs the growth direction of β-Ti dendrites, resulting in the development of round-shaped primary dendrites during the quenching process. These microstructural evolutions of β-Ti dendrites, in turn, lead to an improvement in ductility without a significant compromise in strength. Hence, we propose that fine-tuning the composition to control the primary dendrite morphology can be a highly effective alloy design strategy, enabling the attainment of greater macroscopic plasticity without the typical ductility and strength trade-off.

Constructing novel deep eutectic composites based on hydrogen bond network as anode material for lithium-ion batteries

The replacement of metallic materials with non-metallic materials as anode electrodes for lithium-ion batteries (LIBs) is an increasing hot spot for constructing a new generation of energy storage field. Here, a novel deep eutectic composites material consisting of quaternary ammonium salts (QASs) and N-methyl pyrrolidone (NMP) on the basis of hydrogen bonding reaction is used as the anode material of LIBs, boasting numerous advantages, including facile synthesis, environmental friendliness, superb conductivity, self-healing property, and multiple active sites to provide capacity. Typically, tetraethylammonium chloride (TEACl)/NMP delivered a reversible specific capacity of 764.8 mAh/g at 100 mA/g after cycling 420 times and coulombic efficiency is maintained near 100 % after 1000 cycles at 100 mA/g. The availability of hydrogen bonding network reduces the lattice energy of its components and creates defects, which is more favorable for the intercalation reaction in LIBs. Concurrently, the effect of hydrogen bonding reaction and the natural mobility of the deep eutectic composites exhibit high self-healing properties, facilitating the repair of the reaction interface in real time. An abundance of active sites that can bind Li+ to form LiH is used to provide capacity, which is also confirmed by density functional theory (DFT) method.

Mechanical properties of Al2O3–LaPO4 composites with eutectic microstructure produced by flash sintering

AbstractThe mechanical properties of Al2O3–LaPO4 composites with varying microstructures produced by flash sintering and conventional sintering are evaluated. Specifically, Vickers and Knoop hardness values were measured and calculated for different resultant microstructures, including eutectic microstructures with varying layer thickness, polycrystalline (noneutectic) microstructures, and single‐phase samples of Al2O3, LaPO4, and 8YSZ. The findings indicate that eutectic microstructures exhibited higher hardness values than polycrystalline counterparts on the flash‐sintered sample. However, the hardness values of eutectic microstructures with varying layer thicknesses show no significant or systematic variation. The grain size, indentation size, eutectic colony size, indentation shape (elastic recovery in Knoop indentations), and crack propagation pathways in the indented samples are also discussed. Overall, the results suggest that Al2O3–LaPO4 eutectic composites have higher hardness than their polycrystalline counterparts and have great potential as abradable coatings with high machinability and durability.

Multi-wall carbon nanotubes tailored eutectic composites for solar energy harvesting

Carbonaceous thermal energy storage involving PCMs has gained an increasing research interest owing to their higher thermal conductivity and energy storage density. The current work analyses the thermophysical properties of a nano-enhanced eutectic phase change material (NeUPCM) laden with different concentrations (ranges from 0 wt% - 0.7 wt%) of multi-wall carbon nanotube (MWCNT). Paraffin wax-palmitic acid (PW-PA) binary eutectic was produced initially by facile melt blending, and then MWCNTs were doped via standard two-step nanocomposite synthesis protocol. Nanocomposites showed a slower decomposition rate, and the thermal resistance index improved. MWCNT enhance the thermal conductivity of the eutectic base (140 %), which reaches a maximum value of 0.619 W/(m·K) for 0.5 wt% loadings, and the maximum increment of 13.2 % of latent heat was noted for 0.7 wt% loading of MWCNT (which is having a melting temperature of 53 °C). The sample doped with 0.5 wt% MWCNT(C3) showed the highest thermal effusivity. The NeUPCMs also displayed improved photothermal performance and solar absorptivity. Corrosion analysis against copper revealed that the composite is suitable for long-term usage. The NeUPCMs maintained good reliability even after 500 melt-freeze cycles. In short, the proposed NeUPCMs hold significant potential to be employed for thermal energy storage purposes.

Excellent low-temperature dehydrogenation performance and reversibility of 0.55LiBH4-0.45Mg(BH4)2 composite catalyzed by few-layer Ti2C

The 0.55LiBH4-0.45Mg(BH4)2 (LMBH) eutectic composite is promising for solid-state hydrogen storage, as it exhibits a high hydrogen capacity and a very low initial dehydrogenation temperature. However, its main hydrogen release steps still require higher temperatures. In the present study, few-layer Ti2C has been synthesized and utilized as catalysts in the LMBH. Compositing LMBH with varying amounts of Ti2C (10, 20, 30, and 40 wt%) results in low initial dehydrogenation temperatures (164–110 °C), fast desorption rates and high hydrogen capacities (7.5–10.5 wt%) at a low temperature of 260 °C. The LMBH-30Ti2C composite yields 6.5 wt% H2 even at as low as 200 °C. Additionally, the LMBH-30Ti2C composite could reversibly store 3.5 wt% H2 during the second to fourth dehydrogenation cycles without degradation. The outstanding hydrogen storage performance could be attributed to decomposition driven by reactions between high-valence Ti ions and LMBH, the in-situ formation of the active metal Ti catalyst, and the prevention of aggregation in the Ti2C-doped LMBH.