Hydrogen Storage Alloys Research Articles

Retracted: Preparation of Mg2Ni Hydrogen Storage Alloy Materials by High Energy Ball Milling

Retracted: Preparation of Mg₂Ni Hydrogen Storage Alloy Materials by High Energy Ball Milling

Effect of industrial grade raw materials and its associated impurities on first hydrogenation of BCC solid solution alloys

This study explores the effects of using industrial-grade raw materials on the hydrogen storage properties of body-centered cubic (BCC) solid solution alloys. Industrial scrap metals were chosen as the raw material, and the desired alloys were synthesized using a vacuum arc melting furnace. Instead of using pure vanadium (V), different inexpensive industrial substitutes such as low-grade vanadium (V), vanadium nitride (VN), vanadium oxide (VO), and ferrovanadium (FeV) were utilized. The crystal structure, morphology, first hydrogenation, thermodynamics, and cyclability of the prepared alloys were analyzed by using XRD, SEM-EDS, and XPS methods. The crystal structure and morphology analysis revealed multiphase alloys in all the prepared alloys and a Ti rich third phase in the VN sample, which was absent otherwise. The first hydrogenation was performed at room temperature under a hydrogen pressure of 2 MPa without any prior heat treatment. The VO alloy displayed negligible hydrogen absorption during first hydrogenation, while the V, VN, and FeV alloys showed maximum hydrogen storage capacities of 3.49 wt%, 2.47 wt%, and 2.18 wt%, respectively. The presence of oxygen hinders the activation of the VO alloy and requires two activation cycles to activate the sample. A short-term cyclability analysis showed a reversible hydrogen storage capacity of 2 wt%. The change in enthalpy of hydrogen absorption and desorption for V alloy were calculated to be −36.73 ± 8.6 and 57.34 ± 8.3 kJ/mol H2, respectively. One of the prominent advantages of utilizing scrap raw materials was the substantial reduction in overall raw material costs, which saw an impressive 95% decrease when compared to using pure raw materials. These results highlight the economic benefits of incorporating recovered industrial scrap into hydrogen storage alloys.

Magnesium nickel hydride monocrystalline nanoparticles for reversible hydrogen storage

Although Mg-based hydrides are extensively considered as a prospective material for solid-state hydrogen storage and clean energy carriers, their high operating temperature and slow kinetics are the main challenges for practical application. Here, a Mg–Ni based hydride, Mg2NiH4 nanoparticles (∼100 nm), with dual modification strategies of nanosizing and alloying is successfully prepared via a gas-solid preparation process. It is demonstrated that Mg2NiH4 nanoparticles form a unique chain-like structure by oriented stacking and exhibit impressive hydrogen storage performance: it starts to release H2 at ∼170 °C and completes below 230 °C with a saturated capacity of 3.32 wt% and desorbs 3.14 wt% H2 within 1800 s at 200 °C. The systematic characterizations of Mg2NiH4 nanoparticles at different states reveal the dehydrogenation behavior and demonstrate the excellent structural and hydrogen storage stabilities during the de/hydrogenated process. This research is believed to provide new insights for optimizing the kinetic performance of metal hydrides and novel perspectives for designing highly active and stable hydrogen storage alloys.

(Digital Presentation) Designing New Complex Hydrides Based on Transition Metals for Hydrogen Storage Applications

The widespread implementation of the hydrogen economy demands access to materials with a high weight percentage of hydrogen. Mg-based hydrogen storage alloys have become a research hot-spot in recent years owing to their high hydrogen storage capacity, good reversibility of hydrogen absorption/desorption, low cost, and abundant resources. However, high decomposition temperature of Mg-based hydrideslimits their practical usage. Hydrogen is lightest of all elements, typically it need large volumes or high pressures to store appreciable amount of hydrogen.To overcome these challenges research activities are currently going on metal hydrides and complex hydrides based on transition metal. The main challenges come when endothermic decomposition enthalpy is considered. It becomes difficult to release the hydrogen at ambient thermodynamic conditions. On the other hand, the meta-stable hydrides are characterized by a low reaction enthalpy and a decomposition reaction that is thermodynamically favourable under the ambient conditions. The good kinetics along with evolution of hydrogen around the room temperature possessed by these materials offer much promise for underground storage and it can be used as a grid energy.The present research specifically focus on transition metal based complex hydrides such as NaMgMnH6 and NaMgFeH6 for hydrogen storage and especially predicted the crystal structure of the same using VASP simulation package. ABCX6 and AB2X6 were taken as reference composition A,B,C and X were substituted with Na, Mg, transition metals(Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu) and H, respectively.From the ICSD database search the corresponding structural variants were considered as trial structure to predict the ground state structure of these newly designed compounds. using the predicted ground state structure for these compounds, important properties like formation energy, hydrogen site energy, partial density of states(pDOS), electron density(ED), Mulliken effective charge(MEC), Bader electron charge(BEC), Born effective charge, ELF and COHP were calculated. the calculated properties of these compounds were compared with the well known reference compounds. We found that both NaMgMnH6 and NaMgFeH6 are stable with negative formation energy and als othey are semiconductors with the band gap value of 0.51eV and 1.01 eV, respectively. from the calculated electronic structure we found that both these materials are having indirect band behaviour. Analysing the electronic density of states, charge density and various charges mentioned above the chemical bonding behaviour was established as iono-covalent in nature. from the force as well as stress minimisation considering 53 structural variants as input the ground state structure, its space group, equilibrium lattice parameters and atom positions are listed. Also from the energy vs. volume curve for the ground state structure, the equilibrium volume, bulk modulus and pressure derivatives were found out. Among NaMgMnH6 and NaMgFeH6 our spin polarised calculation show that NaMgMnH6 is possesing spontaneous magnetic polarisation with substantial magnetic moment at the Mn site. Among the considered paramagnetic, ferromagnetic, as well as A-, C-,and G- antiferromagnetic configurations the G type antiferromagnetic configuration is found to be the ground state for NaMgMnH6.

Pulsed laser activation method for hydrogen storage alloys

The activation procedures of metals and alloys, crucial for hydrogen absorption, pose a significant challenge in the large-scale application of metal hydrides. This study introduces, for the first time, the Pulsed Laser Activation (PLA) method for hydrogen storage alloys. We demonstrated that the hydrogen storage ability of an aged (exposed to air for 30 days) Ti11V30Nb28Cr31 body-centered cubic alloy can be restored by scanning the sample with a nanosecond pulsed laser for only 3 min. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) analyses were conducted to investigate structural features that changed in the Ti11V30Nb28Cr31 samples after ageing and after the PLA treatment. Surface remelting, the formation of oxide layers, and crack formation appear to be factors influencing the hydrogen storage ability of the Ti11V30Nb28Cr31 alloy activated via PLA. While the mechanisms involved in the PLA are not clear yet, this procedure paves the way for the development of activation methods based on laser-metal interactions that can be easily applied to metals and alloys for hydrogen storage systems.

Decoupled hydrogen and oxygen evolution for efficient water splitting by using nickel hydride batteries

Cost-effective alkaline water splitting represents a promising and sustainable approach for hydrogen production. However, the prevention of hydrogen/oxygen mixing and the efficient use of unstable renewable energy are challenging issues. Herein, we propose a novel solution involving the integration of a nickel-metal hydride (Ni-MH) battery as a redox mediator and affordable a NiFe LDHs–NiFe alloy gradient hybrid bifunctional catalysts as gas evolution electrodes, effectively decoupling the hydrogen and oxygen evolution processes during water splitting. Then, the hydrogen evolution reaction (HER) cell using hydrogen storage alloy and catalytic electrode only requires 0.28 V and the oxygen evolution reaction (OER) cell using nickel hydroxide and catalytic electrode only requires 0.25 V to reach a high current density of 100 mA cm−2. Furthermore, a NiOOH-Zn cell is introduced as an alternative, replacing the OER reaction with Zn. This NiOOH-Zn cell can be discharged without further energy input. Moreover, such a decoupled water electrolysis system can seamlessly integrate with a Ni-MH battery, providing the flexibility to efficiently convert renewable energy sources into both hydrogen and electricity. This integrated system maximizes the utilization of renewable energy, making a significant contribution to sustainable energy production.

Stoichiometry and annealing condition on hydrogen capacity of TiCr2-x AB2 alloys

This study presents the effect of stoichiometry and annealing condition on Ti–Cr AB2-type hydrogen storage alloys. Prior to annealing the majority phase of the as-cast alloys was the C14 Laves phase, with separate Ti and Cr phases. Annealing treatment (1273 K/14 d) led to a transition from C14 to C15 Laves phase structure. Both C14 (as-cast) and C15 (annealed) cell size increased with Ti content, up to a ratio (Cr/Ti) of 1.6, due to B-site Ti substitution in the lattice up to a limit. Pressure composition isotherm (PCI) measurements demonstrated alloys containing a greater Ti content had a better maximum hydrogen storage capacity (1.5 vs. 1.03 wt%) and lower plateau pressure (9.4 vs. 15.8 bar) at 253 K. Annealing resulted in a lower storage capacity (1.05 vs. 1.49 wt%), greater plateau pressure (ca. 30 bar) and flatter plateau slope (25 % reduction in plateau slope). Reduction in hydrogen storage capacity of annealed alloys could be due to diffusion of residual Cr in the alloy into the C15 Laves phase during the annealing process, thereby changing the local composition as confirmed through X-ray diffraction (XRD).

Optimization of LaNi5 hydrogen storage properties by the combination of mechanical alloying and element substitution

LaNi5 is a commercial hydrogen storage alloy with great potential. But its performance still needs to be optimized to meet the standard proposed by the US Department of Energy. Element substitution is a very important method to optimize the performance of hydrogen storage alloys, especially suitable for AB5 alloys. As a novel method to produce nanocrystalline hydrogen storage alloys, mechanical alloying is also often applied to optimize the properties of hydrogen storage alloys.In this work, first of all, the simulation method based on first principles is applied to predict the performance of 8 elements substituting Ni respectively, and select the most suitable element to substitute Ni. Then the phase composition characterization, hydrogen storage performance tests and electrochemical performance tests were carried out. It was found that mechanical alloying can greatly improve the hydrogen storage performance of LaNi5, and different ball milling times can bring about different performance changes. After adding Cr to the ball-milled LaNi5, the properties of the formed LaNi4Cr were further improved.

Prolonging cycling life of AB3-type superlattice alloys by adjusting hydrogen absorption/desorption behaviors of [A2B4] and [AB5] subunits

AB3-type La-Mg-Ni-based hydrogen storage alloys are known for their high electrochemical hydrogen storage capacity. However, their practical application has been hindered by fast capacity degradation. Herein, we managed to improve their cycle life by synchronizing the hydrogen absorption/desorption behaviors of [A2B4] and [AB5] subunits based on a series of AB3-type single-phase La0.60R0.12Mg0.28Ni3 (R = La, Pr, Nd, Gd) superlattice alloys. This is achieved by the preferable occupation of Pr, Nd and Gd in [A2B4] subunits rather than [AB5] subunits compared to La, which decreases the volume difference between [A2B4] and [AB5], significantly reducing the mismatch between [A2B4] and [AB5] during hydrogen absorption/desorption. Resultantly, the microstrain of the R = Gd alloy is only half that of the R = La alloy, leading to enhanced anti-pulverization and anti-oxidation/corrosion resistance, as well as an improved cycle stability. The S100 of the R = Gd alloy is more than 15 % higher than the R = La alloy. Moreover, the plateau pressure is adjusted to a proper level, enabling an increase in the high-rate dischargeability (HRD1500) from 53.6 % (R = La) to 66.4 % (R = Gd). This work provides impressive insights into developing high-performance superlattice hydrogen storage alloys.

Microstructure and electrochemical properties of cobalt-substituted A2B7-type La–Y–Ni-based hydrogen storage alloys

La–Y–Ni-based superlattice hydrogen storage alloys exhibit key technological advantages as negative electrode materials for Nickel-metal hydride (Ni-MH) batteries; however, the function of Co has not been studied systematically. A series of LaY2Ni10-xMn0.5Cox (x = 0, 0.3, 0.5, and 0.9) alloys with only A2B7-type phases were prepared in this study, and the effects of Co on the microstructure and electrochemical properties were studied. Co has a minor effect on phase composition; however, it increased cell parameters because of its larger atomic size compared to that of Ni. Co-substituted alloys exhibited excellent activation performance and achieved the maximum discharge capacity in the first cycle. Moreover, Co promoted the discharge capacities of the alloys, but aggravated cycling degradation attributed to the accelerated pulverisation of the alloy particles that leads to serious oxidation/corrosion. Furthermore, an appropriate amount of Co enhances the electrochemical kinetics performance by promoting the charge transfer rates on the alloy surface and the hydrogen diffusion rates in the alloy bulk.

Improved hydrogen ab-/desorption performance of Ti–Cr based alloys via dual-effect of oxide reduction and element substitution by minor Al additive

Hysteresis of hydrogen storage alloys essentially hinders the compressibility and operation efficiency of metal hydride hydrogen compressors. In this work, minor Al additive was added into Ti–Cr based hydrogen compression alloys through induction levitation melting, and the apparent hysteresis was successfully ameliorated. The XRD and SEM results indicate homogeneous element distribution of a main C14 Laves phase of Ti0.96Zr0.06Cr1.0Mn0.6Fe0.4Alx (x = 0, 0.01, 0.02, 0.04, 0.08) alloys, and vanishing of a minor oxide phase in case the Al additive is introduced. As Al stoichiometry increases in the alloys, the hydrogenation plateau decreases obviously but the dehydrogenation plateau hardly changes. Meanwhile, the hydrogen capacity ascends initially but descends slightly. Additionally, no severe performance degradation is induced. The mechanism for overall performance improvement can be concluded as dual functions of Al additive: one can be oxide reduction of other elements during melting determined by XPS and ICP, and the other can be partial Al substitution for the B-side elements, leading to relieved deformation energy surrounding the vacant Al-containing interstitials. As to hydrogenation kinetics, the alloys exhibit accelerated hydrogenation rate with increased Al stoichiometry due to decreased activation energy and hydrogenation plateau. Furthermore, the first-principles calculation results indicate random Al substitution for the B-side atoms, and anisotropic expansion of the unit cell can be attributed to Al substitution at 6h sites. This work reveals a simple and effective way to enhance hydrogen storage performance of Ti–Cr based alloys.

Preparation of CO2‐activated Porous Graphene for Enhancing the Electrochemical Hydrogen Storage Properties of Co9S8 Material

AbstractIn this work, Co9S8 hydrogen storage material was synthesized by mechanical alloying. To improve the electrocatalytic activity and conductivity of Co9S8, a series of porous reduced graphene oxide (PRGO) materials were fabricated via a facile CO2 activation treatment of RGO at different processing times. The composites of Co9S8 doping with different amount of PRGO were manufactured through ball milling. During the electrochemical hydrogen storage test, the porous Co9S8+PRGO exhibited higher discharge capacity than Co9S8+NRGO and conventional Co9S8. Moreover, the CO2 activation time and additive amount of PRGO had significant impact on the electrochemical properties of Co9S8. Ultimately, the electrode of 6 wt.% PRGO‐2 modified Co9S8 attained the optimum discharge capacity of 653 mAh/g. The special porous structure and high specific surface area of porous graphene could provide more electrochemical active sites and facilitate the hydrogen diffusion. After PRGO modification, the cycling stability, high‐rate dischargeability (HRD) and kinetic properties of Co9S8 were also enhanced. It can be concluded that porous graphene possesses better effect than conventional graphene in improving the performance of hydrogen storage alloy.

TiFe Hydrogen Storage Alloys Produced by “Hydride Cycle” Method

TiFe Hydrogen Storage Alloys Produced by “Hydride Cycle” Method

Enhancing Hydrogen Storage in AZ31 Alloy through Pd/G Composite

In this research, we investigated the catalytic effects of Palladium/Graphene(Pd/G) on AZ31 alloy for hydrogen storage. X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (SEM-EDS) were employed to confirm the homogeneous distribution of AZ31 and observe phase changes after mechanical alloying with the catalysts. The hydrogen storage properties of AZ31 with catalysts were systematically examined, and the time of maximum reaction rate for nucleation was determined using Avarami Plot. The results of the study show that the incorporation of 2% Pd/G resulted in the fastest hydrogen absorption and desorption time, taking 200 seconds to achieve 90% hydrogen storage with a maximum of 6.04 wt%. The corresponding maximum hydrogen desorption occurred in 694 seconds, reaching 6.03 wt%. Consequently, the introduction of 2% Pd/G catalyst proved to be effective in significantly enhancing the hydrogen ab/desorption rates of AZ31 alloy.

Superior oxygen-resistance and intrinsic mechanisms of coherent Pd/Pd3Zr@ZrCo structure with excellent cycling durability

As a promising candidate for hydrogen isotopes storage, ZrCo alloy suffers tremendously from the poisoning of impurity gases, especially in oxygen-containing atmospheres, but related effective modification method for long cycling durability is still lacking. In this work, the anti-oxygen-poisoning behaviors and mechanisms of virginal ZrCo and palladium-coated ZrCo with different heating evacuation methods were detailly investigated. Notably, the phase transition occurs during traditional heating evacuation (550 °C for 60 min) with the gradual generation of Pd3Zr from original Pd coating and ZrCo substrate. According to absorption behaviors and degeneration state of O πp-orbital peak from theoretical calculations, O2 undergoes spontaneous dissociation and strong hybridization at the surface of ZrCo and Pd3Zr, especially for ZrCo, while much weak surface absorption is recognized on Pd. Considering the superior anti-poisoning properties but weak substrate anchoring strength of Pd, it’s valuable to reconstruct the Pd/ZrCo interface to generate transition Pd3Zr layer that is less susceptible to hydrogen embrittlement. Accordingly, a coherent structure of Pd/Pd3Zr@ZrCo was successfully obtained by high temperature short time pretreatment (550 °C for 10 min), and its cycling capacity retention in O2-containg hydrogen atmosphere is significantly enhanced from initial 74.87 % after 5 cycles to 90.83 % after 10 cycles, which is superior to Pd-plating hydrogen storage alloys ever reported. The interface reconstruction of coherent structure proposed here can function as a promising strategy for construction of protective layer for all related surface engineering.

Composition optimization and hydrogen storage properties of Ti–V–Mn–Fe alloys

Ti–V-based hydrogen storage alloys have garnered interest owing to their salient advantages of reversible hydrogen absorption/desorption at room temperature and excellent kinetic properties. However, the complicated smelting technology of high-purity V metal renders expensive prices, hampering their large-scale production and application. Herein, to overcome this hurdle, abundant and inexpensive Mn and Fe are added to obtain Ti–V–Mn–Fe hydrogen storage alloys. The novel alloy compositions were obtained using a uniform design method. The hydrogen absorption/desorption behaviors of alloys prepared using arc melting technology were analyzed in detail. Systematic investigations show that the activation, kinetics, and thermodynamic properties of alloys are closely correlated with the Ti/(Mn + Fe) ratios. The designed alloy compositions have a multiphase structure with a body-centered cubic (BCC) main phase. The lattice parameters of the BCC phase increase with increasing Ti/(Mn + Fe) ratio, and the large lattice parameters of alloys are beneficial to facilitate the diffusion of hydrogen atoms, resulting in fast kinetics. A reasonable Ti/(Mn + Fe) ratio positively affects the hydrogen storage properties. Among them, the Ti40V40Mn2Fe18 alloy with Ti/(Mn + Fe) = 2 achieved a hydrogen absorption capacity of 3.472 wt% at 298 K and an effective reversible hydrogen storage capacity of 1.485 wt% above 0.1 MPa at 363 K. This study provides a novel insight for designing Ti–V-based alloy compositions via the uniform design method.

Structures and electrochemical performances of La0.7Sm0.3MgNi3·6Co0.4 + xwt.%Ni (x = 0,5,10,15,20) alloys applied to Ni-MH battery

The La–Mg–Ni–Co-based AB2-type alloys, namely La0.7Sm0.3MgNi3·6Co0.4xwt.%Ni (x = 0,5,10, 15, 20), were synthesized through ball milling. The study focused on investigating the impact of Ni content on the structures and electrochemical properties. The structures of the samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Transmission electron microscope (TEM). It has been demonstrated that the experimental samples consist of a primary phase, LaMgNi4, and a secondary phase, LaNi5. The abundance of phases undergoes significant changes with variations in Ni content, while the phase composition remains constant. The results indicate that a rise in Ni concentration results in an elevation of the LaNi5 phase and a reduction of the LaMgNi4 phase. Additionally, ball milling and the addition of nickel contribute to the refinement of the alloy grains. As the nickel concentration reached 20 wt%, the cycle retention rate(S30) of the composite alloy electrode achieved its maximum value of 73.42 %. In addition, the electrochemical kinetic test findings demonstrated that the maximum D value of the hydrogen diffusion system was 1.807 × 10−10 cm2/s and that the maximum current density of the composite hydrogen storage alloy electrode was 723 mA/g when x = 0 wt%.

Development of AB2-type TiZrCrMnFeCoV intermetallic high-entropy alloy for reversible room-temperature hydrogen storage

Intermetallic high-entropy alloys (HEAs) with C14 Laves phase structure have shown promise as hydrogen storage materials due to their ability to maintain the advantages of the AB2-type hydrogen storage alloys while offering the potential for the improvement of hydrogen storage properties through the use of multi-principal elements. However, some intermetallic HEAs are limited in their ability to scale-up production using the low-cost induction melting method and reversible hydrogen storage at room temperature due to their extremely low equilibrium desorption pressure. In this work, intermetallic HEAs with reversible room-temperature hydrogen storage are designed using an empirical model based on calculation of the electronic and geometrical factors. An orthogonal experiment was conducted to optimize the composition and the optimal (Ti1.3Zr0.7)1.1Cr1.1Mn1.8Fe0.3Co0.4V0.4 HEA with a single C14 Laves phase was found to exhibit the best overall hydrogen performance. It can reversibly store 1.84 wt% hydrogen with a relatively low plateau hysteresis factor (0.71) and slope factor (0.89) at a temperature of 15 °C. The dehydrogenation enthalpy and entropy of the optimal HEA were determined to be 35.0 kJ mol−1 and 115.3 J mol−1 K−1, respectively. To reduce the cost of HEAs, FeV80 was employed to replace the V. It was found that the optimal HEA could be successfully scaled-up for production, and our findings demonstrate the potential of intermetallic HEAs for efficient hydrogen storage.

Hydrogen storage properties of AB2 type Ti–Zr–Cr–Mn–Fe based alloys

This investigation explores the solid-state hydrogen storage properties of two series of hydrogen storage alloys: (Ti0.85Zr0.15)xMn0.8CrFe0.2 (x = 1.00∼1.10) and (Ti0.85Zr0.15)1.02MnyCr1.8-yFe0.2 (y = 1.00∼0.40) alloys. These alloys exhibit a single C14-Laves phase structure and demonstrate promising capabilities for solid-state hydrogen storage. The (Ti0.85Zr0.15)xMn0.8CrFe0.2 (x = 1.00∼1.10) alloys display an increased hydrogen absorption capacity and a reduced plateau pressure at higher super-stoichiometric ratios of x. When x = 1.10, the alloy achieves a maximum capacity of 1.86 wt%. The hydrogen storage capacity of the (Ti0.85Zr0.15)1.02MnyCr1.8-yFe0.2 (y = 1.00∼0.40) alloys diminishes as the value of y decreases. Furthermore, the hydrogen absorption plateau pressure and hysteresis factor of the alloys increase with an escalating Mn/Cr ratio. The analysis of cyclic stability reveals that the primary factor contributing to poor cycling stability of the (Ti0.85Zr0.15)1.02Mn0.4Cr1.4Fe0.2 alloy is the compositional decomposition, rather than pulverization or alterations in the phase structure.In summary, this investigation enhances our understanding of the solid-state hydrogen storage properties of these alloys. It establishes a foundation for further research and development in this pivotal field of hydrogen storage.

Compositional tuning of A2B7-type La0.7–xYxMg0.3Ni3.5 alloys for gaseous hydrogen storage

Rare earth-based superlattice alloys have great potential for gaseous hydrogen storage, as well as successful application as nickel-metal hydride batteries anodes. In this work, Y substitution was carried out to adjust the gaseous hydrogen storage properties of A2B7-type La0.7Mg0.3Ni3.5 alloys. The results indicate a multiphase structure in the alloys comprised of the main rhombohedral Gd2Co7 and PuNi3 phases, with a small amount of CaCu5 phase. Moreover, the Y substitution results in higher abundance of the Gd2Co7 phase. The alloy La0.42Y0.28Mg0.3Ni3.5 exhibits a hydrogen storage capacity of 1.55 wt% at 298 K and a desorption plateau pressure of 0.244 MPa. In addition, this alloy demonstrates a stable cycle life by a capacity retention of 94.2% after 50 cycles, with the main capacity degradation occurring during the initial 20 cycles. This work accentuates the potential of the La–Y–Mg–Ni-based superlattice alloys for applications in solid-state hydrogen storage.