Search Results (227)

TiVCr-based alloys are well-explored body-centered cubic (BCC) materials for hydrogen storage applications that can potentially store higher amounts of hydrogen at moderate temperatures. The challenge remains in optimizing the alloy-hydrogen stability, and several transition elements have been found to support the reduction in the hydride stability. In this study, Ni and Nb transition elements were incorporated into the TiVCr alloy system to thoroughly understand their influence on the (de)hydrogenation kinetics and thermodynamic properties. Three different compositions, (TiVCr)₉₅Ni₅, (TiVCr)₉₀ Ni₁₀, and (TiVCr)₉₅Ni₅Nb₅, were prepared via arc melting. The as-prepared samples showed the formation of a dual-phase BCC solid solution and secondary phase precipitates. The samples were characterized using hydrogen sorption studies. Among the studied compositions, (TiVCr)₉₀Ni₁₀ exhibited the highest hydrogen absorption capacity of 3 wt%, whereas both (TiVCr)₉₅Ni₅ and (TiVCr)₉₀Ni₅Nb₅ absorbed up to 2.5 wt% hydrogen. The kinetics of (de)hydrogenation were modeled using the JMAK and 3D Jander diffusion models. The kinetics results showed that the presence of Ni improved hydrogen adsorption at the interface level, whereas Nb substitution enhanced diffusion and hydrogen release at room temperature. Thus, the addition of Ni and Nb to Ti-V-Cr-based high-entropy alloys significantly improved the hydrogen absorption and desorption properties at room temperature for gas-phase hydrogen storage. Full article

In order to improve the hydrogen storage properties of Laves phase AB₂-type alloys, a series of Ti_1−xZr_xMn_1.0Cr_0.85Fe_0.1 (x = 0.1–0.5) alloys were prepared by arc melting. The effects of Zr content on microstructure and hydrogen storage properties was investigated in detail. Crystal structure characterizations confirmed that all the alloys exhibit a single-phase C14 Laves structure, and the lattice parameters increase with increasing Zr content. The hydrogen storage measurements of the alloys indicate that with increasing Zr content, the hydrogen storage capacity initially increases and then decreases. The hydrogen absorption and desorption measurements of the alloys were performed by a Sieverts-type apparatus. Pressure–composition–temperature (P-C-T) tests at various temperatures showed that all the alloys display sloped plateaus. Increasing Zr content results in a gradual decrease in hydrogen absorption and desorption plateau pressures. Moreover, these alloys exhibit varying degrees of hysteresis, which also becomes more pronounced with a rise in Zr content. In summary, the Ti_0.7Zr_0.3Mn_1.0Cr_0.85Fe_0.1 alloy demonstrates the best comprehensive hydrogen storage capacity. Further investigation on the cyclic performance of the Ti_0.7Zr_0.3Mn_1.0Cr_0.85Fe_0.1 alloy was conducted. It was found that the alloy particles undergo significant pulverization after hydrogenation cycles, but the alloy maintained good phase structure stability and hydrogen storage performance. Full article

To address the high cost of cobalt in rare-earth hydrogen storage alloys, this study developed cost-effective low-cobalt and cobalt-free AB₅-type alloys. The results demonstrate that all synthesized alloys displayed a single-phase LaNi₅ structure possessing a homogeneous elemental distribution. Low-cobalt (La, Ce) (Ni, Co, Mn, Al)₅ alloy 4SC and cobalt-free (La, Ce) (Ni, Mn, Al)₅ alloy 7D exhibited similarly excellent electrochemical performance, including high discharge capacity, long cycle life, and superior high-rate discharge (HRD) capability. In addition, the kinetic test results show that the exchange current densities of these two alloys were quite similar, measuring 302.97 mA g⁻¹ and 317.70 mA g⁻¹, respectively. However, the hydrogen diffusion coefficient of 7D was significantly higher than that of 4SC, reaching 9.45 × 10⁻¹⁰ cm² s⁻¹, while that of 4SC was only 5.88 × 10⁻¹⁰ cm²/s. This work establishes a theoretical foundation for industrial-scale and cost-effective AB₅-type hydrogen storage alloys, offering significant commercial potential. Full article

In this study, we address the need for sustainable and scalable synthesis routes for hydrogen storage materials by developing a FeTi alloy in which vanadium (V) partially substitutes for titanium (Ti). The alloy was synthesized using mechanical alloying, compaction, and post-annealing, employing industrial-grade Fe and Ti powders and an alternative to pure vanadium, i.e., ferrovanadium (Fe–V). X-ray diffraction (XRD) analysis of the mechanically alloyed mixture revealed the partial formation of a Fe(V) solid solution, along with residual Ti. Subsequent compaction and annealing at 1000 °C led to the formation of the FeTi(V) phase, accompanied by two minor secondary phases, Fe₂Ti and Fe₂Ti₄O. A maximum phase yield of 90% for FeTi was achieved after 48 h of annealing. The novelty of this work lies in the demonstration of a sustainable and economical synthesis approach for V-substituted FeTi alloys using industrial-grade raw materials, offering a potential reduction in the carbon footprint compared with conventional melting techniques. Full article

Aqueous zinc-ion batteries (AZIBs) have emerged as promising candidates for large-scale energy storage due to their inherent safety, low cost, and environmental sustainability. However, in practical applications, AZIBs are constrained by the adverse reactions originating from the zinc anodes, including dendrite formation, hydrogen evolution reaction, corrosion, and passivation, which hinder their large-scale commercialization. Nowadays, alloying strategies have been recognized as efficient approaches to address these limitations and have gained significant attention. By introducing heterogeneous elements into Zn matrices, alloying strategies can suppress dendrite formation and side reactions, modulate the interfacial kinetic process, and enhance electrochemical stability. This review systematically discusses the advantages of alloying for Zn anodes, categorizes key design strategies, such as surface modifications, composite structures, functional alloying, gradient, and layered alloy designs, and meanwhile highlights their performance improvements. Furthermore, we suggest future directions for advanced alloy development, scalable fabrication design, and integrated system optimization. Alloy engineering represents a critical pathway toward high-performance, durable Zn anodes for next-generation AZIBs and other metal-ion batteries. Full article

As a kind of clean energy, hydrogen energy has great potential to reduce environmental pollution and provide efficient energy conversion, and the key to its efficient utilization is to develop safe, economical and portable hydrogen storage technology. At present, hydrogen storage technology lags behind hydrogen production and use, which is the bottleneck restricting the development of hydrogen energy. In this paper, several current solid-state hydrogen storage methods are reviewed, including hydrate hydrogen storage, alloy hydrogen storage and MOF hydrogen storage. At the hydrogen storage density level, the hydrogen storage capacity of 1K-MOF-5 can reach 4.23 wt% at 77 K and 10 MPa, and remains basically unchanged in 20 isothermal adsorption and desorption experiments. At the level of temperature and pressure of hydrogen storage, the alloy can realize hydrogen storage under ambient conditions. At the economic level, the cost of hydrogen storage in hydrates is only USD 5–8 per kilogram, with almost zero carbon emissions. Through the analysis, it can be seen that the above solid-state hydrogen storage technologies have their own advantages. Although hydrate hydrogen storage is lower than alloy materials and MOF materials in hydrogen storage density, it still has huge potential for utilization space because of its low cost and simple preparation methods. This paper further provides a comprehensive review of the existing challenges in hydrate research and outlines prospective directions for the advancement of hydrogen storage technologies. Full article

Due to environmental concerns and increasing energy needs, hydrogen is increasingly seen as a promising alternative to fossil fuels. Its advantages include minimal greenhouse gas emissions (depending on origin), high efficiency, and widespread availability. Various storage methods have been developed, with high-pressure storage being currently among the most common due to its cost-effectiveness and simplicity. Composite high-pressure vessels are categorized as type III or IV, with type III using an aluminum alloy liner and type IV utilizing a polymer liner. This paper investigates damage mechanisms in filament wound carbon fiber composite pressure vessels subjected to low-velocity impacts, focusing on two types of impactors (with different geometries) with varying impact energies. The initial section features experimental trials that capture various failure modes (e.g., matrix damage, delamination, and fiber breakage) and how different impactor geometries influence the damage mechanisms of composite vessels. A numerical model was developed and validated with experimental data to support the experimental findings, ensuring accurate damage mechanism simulation. The research then analyzes how the shape and size of impactors influence damage patterns in the curved vessel, aiming to establish a relationship between impactor geometry features and damage, which is crucial for the design and applications of carbon fiber composites in such an engineering application. Full article

Magnesium-based alloys, known for their high hydrogen storage capacity, suffer from sluggish kinetics and high activation energy barriers. It can be further optimized through synergistic combinations with metal hydrides. This study aims to address these limitations by investigating the hydrogen sorption properties of AZ31 magnesium alloy combined with different compositions of WS2 nanotubes (NTs) and Pd. The materials AZ31, WS2 (tungsten disulfide) NTs, and Pd were pre-processed via the mechanical ball milling process. Field emission-scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) were employed to investigate the composite morphology and confirm the nanotubular structure of WS₂. This work is among the first to explore the synergistic catalytic effects of WS₂ nanotubes and Pd on the hydrogenation/dehydrogenation behavior of AZ31 alloys. The composite with 8 wt.% WS₂ NT/Pd demonstrated the fastest hydrogen sorption kinetics and a significant reduction in activation energy, from 123.25 kJ/mol to 104.58 kJ/mol. These results highlight the enhanced dehydrogenation performance of AZ31 through catalyst inclusion, offering a promising approach to improve hydrogen storage materials. These findings highlight the potential of combining inorganic NTs and transition metals as effective catalysts to enhance the hydrogen storage performance. This research paves the way for developing advanced hydrogen storage materials with improved performance, contributing to a sustainable energy future. Full article

Interest in hydrogen is rapidly growing due to rising greenhouse gas emissions and the depletion of fossil fuel reserves. Additive manufacturing (AM) is extensively employed to produce high-quality components, with a strong focus on enhancing mechanical properties. The efficiency and cost-effectiveness of AM have further increased interest in its application to manufacturing components capable of withstanding demanding conditions, such as those encountered in hydrogen technology. In this study, 316L stainless steel specimens were fabricated using AM via the selective laser melting (SLM) technique. The specimens then underwent various post-processing heat treatments (PPHT). A subset of these specimens, measuring 50 × 50 × 3 mm³, was tested as electrodes in a water electrolysis cell for oxyhydrogen (HHO) gas production. The HHO gas flow rate and electrolyzer efficiency were evaluated at 60 °C under varying currents. The remaining AM specimens were evaluated for their susceptibility to hydrogen embrittlement under various hydrogen storage conditions, including testing at both room and cryogenic temperatures. Tensile and Charpy impact specimens were fabricated and tested before and after hydrogen charging. The fracture surfaces were analyzed using scanning electron microscopy (SEM) to assess the influence of hydrogen on fracture characteristics. Additionally, as-rolled stainless-steel specimens were examined for comparison with AM and PPHT 316L stainless steel. The primary objective of this study is to determine the most efficient alloy processing condition for optimal performance in each application. Results indicate that PPHT 316L stainless steel exhibits superior performance both as electrodes for HHO gas production and as a material for hydrogen storage vessels, demonstrating high resistance to hydrogen embrittlement. Full article

Superlattice hydrogen storage alloys have attracted much attention due to their high capacity, excellent cyclic stability, and moderate operating conditions. This review, focusing on journal articles published between 2020 and 2025, comprehensively covers the impacts of doping with different rare-earth elements and the substitution of different elements on superlattice hydrogen storage alloys and details the influence mechanisms of different preparation methods, such as arc melting and powder metallurgy, on the phase structure of alloys. A thorough analysis is conducted on how rare-earth element doping alters the crystal structure, lattice parameters, and phase stability of alloys, thereby affecting their hydrogen storage performance. Meanwhile, the differences in the effects of different substituting elements at various substitution sites on the phase structure and hydrogen storage performance of alloys are explored, and the regular patterns and influencing factors are summarized. This review provides a new perspective for the design and development of high-performance superlattice hydrogen storage alloys and is expected to contribute to the long-term and sustainable development of clean hydrogen energy. Full article

High-entropy alloys (HEAs) are a novel class of metallic materials composed of five or more principal elements in near-equimolar ratios. This unconventional composition leads to high configurational entropy, which promotes the formation of solid solution phases with enhanced mechanical properties, thermal stability, and corrosion resistance. Phase stability plays a critical role in determining their structural integrity and performance. This study provides a focused review of HEA phase transitions, emphasizing the role of lattice gas models in predicting phase behavior. By integrating statistical mechanics with thermodynamic principles, lattice gas models enable accurate modeling of atomic interactions, phase segregation, and order-disorder transformations. The combination of computational simulations (e.g., Monte Carlo, molecular dynamics) with experimental validation (e.g., XRD, TEM, APT) improves predictive accuracy. Furthermore, advances in data-driven methodologies facilitate high-throughput exploration of HEA compositions, accelerating the discovery of alloys with optimized phase stability and superior mechanical performance. Beyond structural applications, HEAs demonstrate potential in functional domains, such as catalysis, hydrogen storage, and energy technologies. This review brings together theoretical modeling—particularly lattice gas approaches—and experimental validation to form a unified understanding of phase behavior in high-entropy alloys. By highlighting the mechanisms behind phase transitions and their implications for material performance, this work aims to support the design and optimization of HEAs for real-world applications in aerospace, energy systems, and structural materials engineering. Full article

The ZrCo hydrogen storage alloy is a relatively good hydrogen isotope carrier applied in the National Thermonuclear Fusion Reactor. However, the intrinsic disproportionation characteristics of ZrCo alloy reduces its cyclic service life and limits its further application. To address this issue, Zr_0.8Ti_0.2Co alloy is developed and exhibits good anti-disproportionation performance than pure ZrCo. Nevertheless, Zr_0.8Ti_0.2Co suffers from relatively poor hydrogen absorption kinetics. In this study, the effects of Cr substitution on its microstructure and hydrogen storage performance are investigated. Zr_0.8Ti_0.2Cr_xCo_1−x (x = 0, 0.05, 0.1, 0.15) samples are composed of the ZrCo main phase. After Cr substitution, the second phases of CoZr₂ and TiCr₂ Laves phases appear. With the increase in Cr content, the lattice constant and unit cell volume of the Zr_0.8Ti_0.2Co alloy increase. Meanwhile, the hydrogen absorption incubation time of the Zr_0.8Ti_0.2Co alloy is shortened, and the activation performance is enhanced, which is attributed to the catalytic effect of the Laves second phases. The enthalpy of hydrogen absorption of the Zr_0.8Ti_0.2Co alloy increases, and the stability of the hydride is enhanced with increasing Cr addition. Zr_0.8Ti_0.2Cr_0.05Co_0.95 demonstrates excellent hydrogen desorption kinetics while maintaining robust anti-disproportionation performance. The element substitution and the composition design are effective approaches to improving the comprehensive hydrogen storage performance of ZrCo-based alloys, which provides guidance for its further application. Full article

This study employed annealing heat treatment ranging from 900 to 1300 °C to systematically investigate the effects of annealing temperature on the microstructure and hydrogen storage performance of the equimolar TiZrCrMnFeNi high-entropy alloy. The research indicates that the TiZrCrMnFeNi high-entropy alloy is composed of the C14 Laves phase and a small amount of cubic phase. Compared to the as-cast alloy, the alloy annealed at high temperature (1000~1200 °C) exhibited increased microstructure homogeneity, a higher content of the C14 Laves phase, and a significant enhancement in hydrogen storage capacity. The annealing heat treatment led to changes in the unit cell volume of the C14 Laves phase, with an inverse relationship between unit cell volume and hydrogen absorption and desorption plateau pressures. An increase in unit cell volume resulted in a lower desorption plateau pressure, making the desorption reaction more difficult and consequently increasing the enthalpy change for desorption. This study not only reveals the intrinsic relationship between annealing temperature and the hydrogen storage performance of high-entropy alloys, but also provides significant experimental evidence and theoretical guidance for the design and development of high-entropy alloy materials with excellent hydrogen storage characteristics. Full article

Hydrogen became one of the most studied energy carriers after the global energy crisis and can replace gas and oil as clean fuels. The main challenge is its safe storage and long-distance transportation: steel is among the materials most used for hydrogen storage and transportation. However, steel is susceptible to hydrogen embrittlement (HE). HE can be prevented by depositing hydrogen barrier coatings on the steel surface. This review provides an overview of the hydrogen permeation mechanism and the analytical methods employed to evaluate the performance of the hydrogen permeation barriers. The focus is on Ni and electroless Ni-P coatings deposited on steel as hydrogen barriers. These coatings have been used so far for their anti-corrosion and wear properties; they are currently of interest due to their low hydrogen permeability. The simplicity of production and the possibility of achieving a homogeneous coating, regardless of the geometry of the substrate, make the electroless deposition process of the Ni-P alloy a candidate for ‘in situ’ applications in existing pipelines. This process can be implemented by using and adapting the established pig batch technology. Full article

LiAlH₄, characterized by high hydrogen capacity and metastable properties, is regarded as a promising hydrogen source under mild conditions. However, its reversible regeneration from dehydrogenated production is hindered thermodynamically and kinetically. Herein, we demonstrate an active Li–Al–Ti nanocrystalline alloy prepared by melt spinning and cryomilling to enable directly synthesizing nano-LiAlH₄. Due to the non-equilibrium preparation methods, the grain/particle size of the alloy was reduced, stress defects were introduced, and the dispersion of the Ti catalyst was promoted. The refined Li–Al–Ti nanocrystalline alloy with abundant defects and uniform catalytic sites demonstrated a high reactivity of the particle surface, thereby enhancing hydrogen absorption and desorption kinetics. Nano-LiAlH₄ was directly obtained by ball milling a 5% Ti containing Li–Al–Ti nanocrystalline alloy with a grain size of 17.4 nm and Al₃Ti catalytic phase distributed under 20 bar hydrogen pressure for 16 h. The obtained LiAlH₄ exhibited room temperature dehydrogenation performance and good reversibility. This finding provides a potential strategy for the non-solvent synthesis and direct hydrogenation of metastable LiAlH₄ hydrogen storage materials. Full article