A-site Atoms Research Articles

Enhanced single-atom cobalt layer in MAX phase for biomass electrooxidation integrated with hydrogen evolution

MAX phases have attracted considerable interest due to their structural diversities and potential applications. More than 150 MAX phases have been synthesized, especially expanding the range of A-site atoms from traditional main group elements to subgroup elements with outer layer d electronic structure. However, the functional applications for MAX phases remain somewhat limited. The A-site elements in MAX phases can amplify their inherent properties, transforming primary structural materials into multifunctional materials. As highly catalytic elements, introducing cobalt into the A-site of MAX phases can reveal surprising catalytic activities. Hence, the MAX phase with single-atom-thick cobalt layers was synthesized via an A-site alloying strategy in this work. The obtained V2(Sn2/3Co1/3)C MAX phase demonstrates efficient electrocatalysis in 5-hydroxymethylfurfural (HMF) oxidation reaction along with hydrogen evolution reaction (HER). In-situ electrochemical studies discover that HMF can prevent the self-reconstruction of MAX phase and oxygen evolution reaction (OER). The overall reaction reaches 94.4 % yield to 2,5-furandicarboxylic acid (FDCA) at 1.60 V. Density functional theory calculations suggest that the Co-Sn bimetallic synergy in the A-site promotes the reaction. This groundbreaking investigation into using MAX phases for biomass upgrading highlights their potential in green chemistry and beyond.

Insight into the Rate-Determining Step in Photocatalytic Z-Scheme Overall Water Splitting by Employing A Series of Perovskite RTaON2 (R = Pr, Nd, Sm, and Gd) as Model Photocatalysts.

Photocatalysis is an intricate process that involves a multitude of physical and chemical factors operating across diverse temporal and spatial scales. Identifying the dominant factors that influence photocatalyst performance is one of the central challenges in the field. Here, we synthesized a series of perovskite RTaON2 semiconductors with different A-site rare earth atoms (R = Pr, Nd, Sm, and Gd) as model photocatalysts to discuss the influence of the A-site modulation on their local structures as well as both physical and chemical properties and to get insight into the rate-determining step in photocatalytic Z-scheme overall water splitting (OWS). It is interesting to find that, with a decreasing ionic radius of the A-site cations, the RTaON2 compounds exhibit continuous blue shift of light absorption and a concomitant reduction in the lifetime of photogenerated carriers, revealing a significant influence of A-site atoms on the light absorption and charge separation processes. On the other hand, the A-site atomic substitution was revealed to significantly modulate the valence band positions as well as surface oxidation kinetics. By employing the Pt-modified RTaON2 as H2-evolving photocatalysts, the activity of photocatalytic Z-scheme OWS for hydrogen production on them is found to be determined by its surface oxidation process instead of light absorption or charge separation. Our results give the first experimental demonstration of the rate-determining step during the photocatalytic Z-scheme OWS processes, as should be instructive for the design and development of other efficient solar-to-chemical energy conversion systems.

Improved microwave dielectric properties of LaZn1/2Ti1/2O3 through Y3+ substitution

LaZn1/2Ti1/2O3 is a double perovskite with promising microwave dielectric properties for applications towards dielectric resonators and antennas. Its dielectric properties can be enhanced through the substitution of suitable ions in either A- or B-sites. In this paper, we report a significant improvement in the quality factor (Q) by substituting Y3+ in the La site with a marginal reduction in dielectric constant (εr). A single phase is confirmed in XRD indicating the formation of La1-xYxZn1/2Ti1/2O3 (0 ≤ x ≤ 0.25) solid solutions. The substitution results in an expansion of lattice along the b direction while there is a contraction in both a and c directions, leading to a reduction in unit cell volume. The dielectric constant, εr, is observed to reduce from 33.4 to 29.6 due to the polarizability of A-site atoms. The temperature coefficient of resonant frequency (τf) increases with an increase in x which does not appear to correlate with reducing tolerance factor (t). This non-conventional behaviour of τf in this perovskite based solid solutions brings bond valence of O site (VO) into picture. VO appears to show competing effect on τf. The non-monotonic behaviour is observed in Q×f with a maximum value of 41,400 GHz at x = 0.15 and a sharp decline for x > 0.15. This observation is correlated with variations in the A-site bond valence (VA) and a long-range ordering (LRO) of B-site ions. LRO is associated with Ag mode at 710 cm−1 in the Raman spectra. The low frequency (< 250 cm−1) Raman modes shift to a higher frequency with the increase in Y3+. Y3+ substitution also induces lattice distortion which is discussed in terms of variations in FWHM and relative intensity of the Raman modes.

Comprehensive investigation of structural, magnetic, electronic, optical, mechanical, and piezoelectric properties of ATiO3 (A= Mn, Fe, Ni) compounds for sustainable energy materials.

This work employs Density Functional Theory (DFT) to investigate the characteristics of ATiO3 (A= Mn, Fe, Ni) by utilizing GGA and DFT+U formalisms. Our results reveal that the investigated compounds exhibit a ground-state magnetic arrangement in the G-type antiferromagnetic configuration. Substitution of the A-site atoms along the row leads to a decrease in volume due to poor electronic shielding effects with transition metals. All systems investigated are stable under dynamical conditions, with no imaginary phonon. From the formation energy calculations, NiTiO3 was identified as the most formable and stable compound. DFT+U was most effective for FeTiO3, resulting in significantly wider bandgaps compared to the GGA-level bandgaps. Optical properties such as static dielectric constants, refractive index, and reflectivity were overestimated by the GGA when compared to DFT+U results. The absorption edges of FeTiO3, MnTiO3, and NiTiO3 were analyzed, with DFT+U showing delayed onset compared to GGA. FeTiO3 was found to be the most effective absorber within the visible spectrum according to DFT+U, while NiTiO3 was predicted to be the best absorber by GGA. Each compound's mechanical stability was tested and verified based on the Born criteria, with FeTiO3 exhibiting the highest elastic moduli under DFT+U, while NiTiO3 had the highest shear and Young's modulus according to GGA. Among the studied compounds, FeTiO3 is the best-performing and most efficient piezoelectric compound with e_16 = 5.418 C m^(-2) under DFT+U. Overall, the studied compounds demonstrate promising capabilities for a wide range of applications in the field of photovoltaic devices, and piezoelectric materials, due to their remarkable optical, and piezoelectric properties.

Computational and experimental investigations on structural, electronic and optical properties of scheelite compounds

Oxide of tungstate has consistently been pursued for use in optoelectronic applications. This study details the synthesis of AWO4 (A = Ba, Sr and Ca) using a high-temperature solid-state method. Additionally, theoretical calculations highlight its electronic structure, density of states, photoelectric properties, and vibrational modes. The x-ray diffraction of AWO4 (A = Ba, Sr and Ca) was meticulously introduced by the utilization of Rietveld for refinement. The refined lattice parameters substantially verified AWO4 (A = Ba, Sr and Ca) as a tetragonal system of scheelite with the spatial group of I41/a, and demonstrated significant alteration with the discrepancy in the radius of alkaline earth metal (A-site) ions. The electronic configuration and optical attributes of AWO4 (A = Ba, Sr and Ca) possessing scheelite-like structure were explored using density functional theory (DFT) based computational techniques. The theoretical blueprint was derived by optimizing the structure based on defects. The postulated optical bandgap energy confirms the occurrence of direct electronic transitions at Brillouin region G points. Calculations suggested the direct band gaps of BaWO4, SrWO4, and CaWO4 at 4.385, 3.123 and 3.813 eV. This was attributed to the energy levels produced by O and A-site atoms in the valence band, and W and O atoms in the conduction band. An examination of the polarization effect and uneven electronic charge distribution between [CaO8]6− and [WO4]2− clusters brought about by structural defects in AWO4 (A = Ba, Sr and Ca) was performed. Moreover, advanced investigations have been conducted on the elastic constants and mechanical durability of AWO4 (A = Ba, Sr and Ca). This research extensively calculated the elastic moduli of various matrices utilizing DFT. The critical Pugh’s ratio value was found to be >1.75, it indicated that AWO4 (A = Ba, Sr and Ca) has significant potential as a resilient material.

The A-site and B-site regulation of LaCoO3 nanofiber based on electrospinning for boosting photocatalytic CO2 conversion

Photocatalytic CO2 reduction with perovskite can effectively address both energy and environmental issues. Nevertheless, it remains challenging to prepare photocatalysts with suitable hollow tubular structures in rational. Herein, the La1-xSrxCo1-δFeδO3 nanofiber with a hollow tubular structure was fabricated through an electrospinning method. The hollow nanofiber structure was constructed by doping Sr atoms in the A-site and Fe atoms in the B-site of LaCoO3 perovskite. The characterization of TEM proved that the hollow tubular structural La1-xSrxCo1-δFeδO3 nanofiber exhibited an external diameter of about 95 nm and an internal diameter of about 50 nm. The hollow tubular structural La1-xSrxCo1-δFeδO3 nanofiber showed superior carrier separation ability which could exhibit significant advantages for photocatalytic CO2 reduction. The CH3OH generation rate over the optimized La0.8Sr0.2Co0.7Fe0.3O3 nanofiber could reach 5.25 µmol⋅g−1⋅h−1. This work highlighted an electrospinning strategy to build a hollow tubular structural La1-xSrxCo1-δFeδO3 nanofiber for enhancing photoreduction CO2.

Regulation A-site of ruthenium pyrochlores to enhance acidic oxygen evolution activity and stability

Exploring the relationship between A-site atoms and the ruthenium pyrochlore oxides (A2Ru2O7) structure is crucial for designing efficient electrocatalysts for acidic water oxidation. Here, we manipulate A-site atoms by introducing lanthanide elements (Nd, Sm, Eu, and Ho) in a rational manner. It was shown that different A-site atoms have little effect on the electronic valence of the Ru and O ions, but they do impact the structure of A2Ru2O7. The catalyst activity and stability increased gradually as the A-site ion radius decreased. Ho2Ru2O7 with the lowest Ru content displayed the lowest overpotential (280 mV) at 10 mA/cm2, showing the longest stability (>20,000 s) compared to the other samples. This study suggests that regulating non-active sites can enhance the performance of acidic water splitting.

Development of a baseline model for MAX/MXene synthesis recipes extraction via pre-trained model with domain knowledge

Due to their unique combination of metallic- and ceramic-like properties, MAX phases have attracted a lot of attentions. By selectively etching A-site atoms, MXenes with unique two-dimensional structures can be potentially generated. Due to their extraordinary properties, MXenes have currently made their way to the forefront of various research areas including electronics, photonics and catalysis. Therefore, the development of novel synthesis strategies for MAX/MXene is a key issue for the further development of MAX/MXene. Distilling insights from scientific literatures could accelerate the exploration of novel synthesis recipes; however, manually extracting scattered information from thousands of journal articles is laborious. In this study, we present an annotated corpus incorporating domain knowledge about MAX/MXene synthesis processes, deriving from experimental sections within 110 papers on MAX/MXene research; and based on that, a baseline model (including named entity recognition (NER) and relation extraction (RE) parts) is proposed for distilling information about MAX/MXene synthesis conditions from literatures using pre-trained natural language processing (NLP) models. We also demonstrate the efficacy of the proposed pipeline owning to the joint effort of domain knowledge (about MAX/MXene) and machine learning; where the entity recognition model possessing optimized setting could detect the entities with F1 score of 0.8452, and for relation extraction model with F1 score of 0.8476. It is hoped that the current work would provide an auxiliary for the future research and development of novel MAX/MXenes. In addition, the developed model could serve as a pre-trained model of MAX/MXenes synthesis routes extraction for future data augment.

VecMap: A Python-based Graphic User Interface Tool for Atomic Displacement Mapping in Perovskite Structures.

VecMap, a python-based graphic user interface tool was developed to help analyzing the atomic displacements in perovskite ceramics. With an input of a high-resolution STEM image in which the A-site, B-site, and/or O columns clearly resolved, VecMap outputs the displacement vector maps of either A-site or B-site cations, as well as the oxygen vector map if O columns are visible, in a highly automated fashion. A "Coupled HAADF-ABF" function was specially designed for easy atom finding in ABF images, in case the A-site and B-site atoms are too close in atomic numbers to show enough contrast. VecMap greatly simplifies the analysis of atomic displacement in perovskite structures.

Packing fraction induced phase separation in A-site doped antiperovskites

Local phase separation displayed by the A site doped Mn 3 Sn 1 − x A x C antiperovskites is investigated by studying a series of compounds wherein, the doped A site atoms inflicts changes in electronic contribution to the valence band while keeping the average size of the A site similar (In for Sn), or the size of the A-site atom is varied while maintaining the electronic density constant (Ge for Sn) or both, size and electronic density are varied (Zn for Sn). The study shows that the phase separation is a result of varied distortion of Mn 6 C octahedra due to the difference in the packing fractions of the unit cells. This distortions of the Mn 6 C octahedra are responsible for the observed magnetic properties of these antiperovskite compounds. • All A site substituted antiperovskite compounds, though have a cubic structure, display a local phase separation. • The Mn 6 C octahedra are distorted and the extent of distortion depends on the packing fraction of the unit cell. • Local phase separation and the distortions of the Mn 6 C octahedra play a decisive role in magnetic ground state of these antiperovskite compounds.

High-entropy perovskite RETa3O9 ceramics for high-temperature environmental/thermal barrier coatings

Four high-entropy perovskite (HEP) RETa3O9 samples were fabricated via a spark plasma sintering (SPS) method, and the corresponding thermophysical properties and underlying mechanisms were investigated for environmental/thermal barrier coating (E/TBC) applications. The prepared samples maintained low thermal conductivity (1.50 W·m−1·K−1), high hardness (10 GPa), and an appropriate Young’s modulus (180 GPa), while the fracture toughness increased to 2.5 MPa·m1/2. Nanoindentation results showed the HEP ceramics had excellent mechanical properties and good component homogeneity. We analysed the influence of different parameters (the disorder parameters of the electronegativity, ionic radius, and atomic mass, as well as the tolerance factor) of A-site atoms on the thermal conductivity. Enhanced thermal expansion coefficients, combined with a high melting point and extraordinary phase stability, expanded the applications of the HEP RETa3O9. The results of this study had motivated a follow-up study on tantalate high-entropy ceramics with desirable properties.

New anti-ferromagnetic tri-transition quaternary perovskites for magnetic cloaking and spintronic applications

Magnetism in new tri-transition A-site ordered quaternary perovskites ACu3V4O12 (A = Mn and Cu) are studied using generalized gradient approximation with Hubbard potential (GGA + U) in the domain of density functional theory. The effective Heisenberg model estimates the magnetic exchange coupling constants (J1, J2 and J3) between the spins of Mn and Cu sites. The exchange constants J1 and J3 in MnCu3V4O12 and Cu(1)Cu3(2)V4O12 reveal their long rang interactions through super exchange mechanism. The ground state magnetic order is explained from the optimized energy curves; which reveal the G-type anti-ferromagnetic (AFM) order of MnCu3V4O12 and A-type AFM order of Cu(1)Cu3(2)V4O12. Heisenberg model and magnetic susceptibility are in well agreement in the estimation of Neel temperature 15.1/50 and 15.6/25 K respectively. There is a strong correlation between the magnetism of the A-site atoms (Mn, Cu(1), and Cu(2)), as well as the metallic character of the B-site atoms (V, as well as the tiny contribution of A-site Cu(2) and Mn atoms). Due to AFM metallic nature it is expected that these compounds could be used in spintronic technology and magnetic cloaking devices.

Effects of A-site atoms in Ti2AlC and Ti3SiC2 MAX phases reinforced Mg composites: Interfacial structure and mechanical properties

AZ91D magnesium composites reinforced by Ti3SiC2 MAX phase were fabricated by the stir casting technique. Tensile tests reveal that the reinforced effects of Ti3SiC2 and Ti2AlC on Mg matrix are different. Unlike Ti2AlC-AZ91D composite for which Ti2AlC delamination happens during the fracture, Ti3SiC2-AZ91D composite fractures by interfacial debonding mechanisms. Transmission electron microscopy characterization shows that few nanometric Mg grains form in the vicinity of Ti3SiC2 particles, while huge amount of nanometric Mg grains form along with Ti2AlC particles. Elements mapping confirms that Al atoms of Ti2AlC diffuse into Mg matrix. In contrast, no outward diffusion of Si of Ti3SiC2 is observed. This outcome points out that it is possible to regulate the mechanical properties of their relevant Mg composite through adjusting the content of Al and Si in MAX phases, such as Ti3SiAlC2 solid solution.

Effect of Li and Li-RE co-doping on structure, stability, optical and electrical properties of bismuth magnesium niobate pyrochlore

New Bi1.5Mg0.9-xLixNb1.5O7–δ (x = 0.25; 0.40) and Bi1.4RE0.1Mg0.5Li0.4Nb1.5O7–δ (RE – Eu, Ho, Yb) compounds with the pyrochlore structure were synthesized. The displacements of the A-site atoms (96g) and O' ones (32e) as well as the Li and RE atoms distribution in the A-sites were determined. The dopant distribution was proven by ab initio calculations. The most preferable (Bi1.5Li0.5)(Nb1.5Mg0.5)O7 model was predicted with a direct band gap of 3.18 eV corresponding to the experimental Eg for Bi1.5Mg0.5Li0.4Nb1.5O7–δ. The thermal stability of the compounds in air up to 1100–1220 °C and the reducing atmosphere up to 400 °C was determined. The charge disbalance in the A2O' sublattice and the oxygen vacancies predetermine the dielectric behavior of the ceramics up to 200 °C, the mixed conductivity at high temperatures (T > 200 °C), and the proton transport up to 400 °C.

Local structural mechanism for phase transition and ferroelectric polarization in the mixed oxide K0.5Na0.5NbO3

$({\mathrm{K}}_{x}{\mathrm{Na}}_{1\ensuremath{-}x}){\mathrm{NbO}}_{3}$ (KNN) and its solid solutions are considered as potential alternatives to traditional Pb-based piezoelectric materials. Recent investigations indicated that the local structure in KNN is much more complex than its long-range average structure. Here, we have undertaken a systematic investigation of the temperature-dependent evolution of local and average structures of KNN5 $[({\mathrm{K}}_{x}{\mathrm{Na}}_{1\ensuremath{-}x}){\mathrm{NbO}}_{3},x=0.5]$ using time of flight neutron scattering. Rietveld analysis of neutron diffraction patterns indicated that the average structure of KNN5 changes from monoclinic to tetragonal to cubic upon heating from 100 to 773 K. In contrast, analysis of neutron pair distribution function (PDF) indicated that the local structure stays monoclinic within the above temperature range. Based on comparative analysis of local and average structures, it is proposed that the average structural phase transitions in KNN5 are partly derived from a local ordering of the polar units, which are correlated over a length of 10 \ensuremath{\sim} 15 \AA{}. A clear indication of order-disorder type transition at 473 K is evident from the temperature-dependent PDF patterns. Additionally, based on local structural analysis, it is shown that large electrical polarization in KNN5 can be attributed to displacements of both A-site and B-site atoms. These structural insights may help in further optimization of electrical properties of Pb-free KNN piezoceramics.

A comprehensive study of pressure dependent phase transitions in ferroelectric PbTiO3, PbZrO3 and BaTiO3

Using first principles calculations, we investigate the pressure dependent polarization and phase transitions, based on the structural, electronic, piezoelectric and elastic properties in PbTiO3-P4mm, BaTiO3-P4mm, PbZrO3-R3m and BaTiO3-R3m. Under positive pressure, only PbZrO3-R3m does not exhibit a structural phase transition to paraelectric cubic and has a higher polarization than PbTiO3-P4mm beyond 38 GPa. BaTiO3-P4mm and PbZrO3-R3m show an isomorphic phase transition which is driven by the change in the bonding between A-site and B-site atoms (Ba–Ti) and between the B-site and O-axial atoms (Zr–O), respectively. We quantitatively demonstrate the strong correlation of polarization with octahedral tilt in PbTiO3 and both phases of BaTiO3. The higher polarization in PbTiO3 and PbZrO3 under pressure is on account of the enhanced contributions from Pb atoms and the difference in their energy level shifts with respect to the Fermi level in comparison with that of Ba. We report that the anomalous enhancement in the polarization at negative pressures is a precursor of the onset of the mechanical instability in the material. The onset of mechanical instability is also the region of a node in piezoelectric constants dij.

Spin ordering and physical properties of NaPrFeWO6 and NaSmFeWO6 with polar double perovskite structure

NaPrFeWO6 and NaSmFeWO6 have been synthesized as polycrystalline powders by means of a sol-gel route. Both samples adopt a noncentrosymmetric structure derived from the simple perovskite ABO3 and characterized by a layered ordering of A-site atoms (Na and rare earth) and a rock-salt ordering of B-site atoms (Fe and W) as deduced from x-ray and neutron powder diffraction techniques. Magnetization measurements revealed antiferromagnetic ordering below TN ≈23 K in both compounds but weak spontaneous magnetization is observed in the hysteresis loops of the samples above and below TN revealing a parasitic ferromagnetic component that comes from minor ferromagnetic impurities. The magnetic structure of NaPrFeWO6 is formed by two antiferromagnetic sublattices (rare earth and Fe) that follow the same propagation vector k = (½, 0, ½). The magnetic structure is purely collinear with the moments oriented along the b-axis. It presents competitive magnetic interactions and reduced ordered moments at low temperatures. The rare earth moments in the zig-zag chains running along a (parallel to the ab plane) are ordered following a sequence typical of an E-type arrangement (up-up-down-down). Each Fe2+ atom has four nearest Pr3+ neighbors and it is coupled antiferromagnetically to three of them and ferromagnetically to the fourth one. Strong neutron absorption from Sm atoms hinders obtaining reliable neutron patterns of NaSmFeWO6 for Rietveld analysis but the comparison of neutron patterns above and below TN detected the same magnetic peaks indicating a similar magnetic structure. Dielectric measurements are compatible with a paraelectric system with a strong Maxwell-Wagner contribution from depletion layers and electrical properties are dominated by leakage currents.

First-principles study of polarization and piezoelectricity behavior in tetragonal PbTiO3-based superlattices**Project supported by the National Natural Science Foundation of China (Grant No. 11372085) and the Shenzhen Science and Technology Project (Grant No. JCYJ20150625142543461).

Using first-principles calculation, the contribution of A-site and B-site atoms to polarization and piezoelectricity d33 in the tetragonal PbTiO3/KNbO3 and PbTiO3/LaAlO3 superlattices is investigated in this paper. It is shown that PbTiO3/KNbO3 superlattice has larger polarization and d33 than PbTiO3/LaAlO3 superlattice, because there is stronger charge transfer between A(B)-site atoms and oxygen atom in PbTiO3/KNbO3 superlattice. In PbTiO3/KNbO3 superlattice, B-site atoms (Ti, Nb) make larger contribution to the total polarization and d33 than the A-site atoms (Pb, K) because of the strong covalent interactions between the transition metal (Ti, Nb) and the oxygen atoms, while piezoelectricity in PbTiO3/LaAlO3 superlattice mainly ascribes to piezoelectric contribution of Pb atom and Ti atom in PbTiO3 component. Furthermore, by calculating the proportion of the piezoelectric contribution from PbTiO3 component in superlattices, we find there is different response of strain to piezoelectric contribution from PbTiO3 component in two superlattices but still with a value larger than 50%. In PbTiO3/KNbO3 superlattice, the c-axis strain reduces the proportion, especially under tensile condition. Meanwhile in PbTiO3/LaAlO3 superlattice, PbTiO3 plays a leading role to the total d33, especially under compressive condition, and the proportion decreases as the tensile strain increases.

Comparison of corrosion behavior of Ti3SiC2 and Ti3AlC2 in NaCl solutions with Ti

Corrosion behavior of self-sintered, ternary-layered titanium silicon carbide (Ti3SiC2) and titanium aluminum carbide (Ti3AlC2) fabricated by an in-situ solid-liquid reaction/hot pressing process was investigated by potentiodynamic polarization, potentiostatic polarization and electrochemical impedance spectroscopy in a 3.5% NaCl solution. Commercially pure titanium (Ti) was selected for comparison through XRD, XPS, SEM and EDS examinations for elucidating both the passivation behavior and corrosion mechanism of the alloys. Both Ti3SiC2 and Ti3AlC2 exhibited significantly superior passivation characteristics compared to Ti; Ti3SiC2 also showed better corrosion resistance. The silicon/aluminum site is prone to attack, and the difference in the diffusion rate between the A-site atoms and titanium decreases the passivation ability of the MAX phase. CP titanium exhibited a lower passivation current density and did not undergo breakdown in the test potential region while two MAX phases are destroyed. Nevertheless, the corrosion resistances of Ti3SiC2 and Ti3AlC2 are comparable to that of CP titanium.

Studies on Incorporation of Mg in Zr-Based AB2 Metal Hydride Alloys

Mg, the A-site atom in C14 (MgZn2), C15 (MgCu2), and C36 (MgNi2) Laves phase alloys, was added to the Zr-based AB2 metal hydride (MH) alloy during induction melting. Due to the high melting temperature of the host alloy (&gt;1500 °C) and high volatility of Mg in the melt, the Mg content of the final ingot is limited to 0.8 at%. A new Mg-rich cubic phase was found in the Mg-containing alloys with a small phase abundance, which contributes to a significant increase in hydrogen storage capacities, the degree of disorder (DOD) in the hydride, the high-rate dischargeability (HRD), and the charge-transfer resistances at both room temperature (RT) and −40 °C. This phase also facilitates the activation process in measurement of electrochemical discharge capacity. Moreover, through a correlation study, the Ni content was found to be detrimental to the storage capacities, while Ti content was found to be more influential in HRD and charge-transfer resistance in this group of AB2 metal hydride (MH) alloys.