16d Sites Research Articles

Cation Distribution Effect on Structural and Electronic Properties of Oxygen Vacancy and Niobium Substituted Spinel Lithium Titanium Oxide Anode Material in Lithium-ion Batteries

We have presented the results of detailed studies of oxygen vacancy and niobium (Nb) substituted spinel Li4Ti5O12 (LTO) materials using first-principles method within the framework of the density functional theory (DFT). We have shown that the ground state of oxygen vacancy and Nb substituted LTO is paramagnetic (PM), and the Nb substitution is most stable on the 16d sites of both the Li and Ti ions. We have indicated that the Nb substitution in the 16d site of Li ion become the n-type metallic material. But the oxygen vacancy containing NbT i substituted LTO is changed from the p-type to the n-type, as increased a concentration of Nb ions.

Effect of the crystal structure and chemical bonding on the electronic and thermal transport in Cu2MeHf3S8 (Me – Mn, Fe, Co, Ni) thiospinels

Establishing the relationship between crystal structure and transport properties is an important issue that is directly connected with the applicability of functional materials. In this work, we present the analysis of the crystal structure, chemical bonding, and electronic and thermal transport properties of Cu2МеHf3S8 (Ме – Mn, Fe, Co, Ni) compounds. The increase of weighted mobility in the Mn → Fe → Со → Ni series as well as the change of the dominant scattering mechanism of charge carriers from scattering on point defects to the scattering on acoustic phonons explains the best electronic transport in Cu2NiHf3S8. Moreover, bonding inhomogeneity between the covalent δ(Co – S) and δ(Hf – S) from one side, and more ionic δ(Cu – S) interactions from the other side leads to low lattice thermal conductivity in Cu2MeHf3S8 (Me – Mn, Fe, Co, Ni) materials. The work also suggests the link between the occupation of the octahedral 16d site and the thermoelectric performance of the investigated thiospinels. Particularly, the best thermoelectric performance is observed in the case of the presence of two valence electrons in the d-level of atoms in octahedral voids, which can be essential for further enhancement of the thermoelectric performance in thiospinels.

Unveiling the role of Ni doping in the electrochemical performance improvement of the LiMn2O4 cathodes

Ni doping is a commonly used strategy to improve the electrochemical performance of LiMn2O4. Uncovering the structural changes of Ni-doped LiMn2O4 during electrochemical cycling, particularly at the atomic level, is important to understand the mechanism of the relationship between Ni doping and performance improvement. Herein, we investigate the chemical and structural evolutions of the Ni-doped LiMn2O4 electrodes before and after 1000 cycles at 10 C with atomic resolution and correlate them with changes in the electrochemical properties. We found that Ni2+ ions doped into the Mn 16d sites to form a more steady LiNixMn2-xO4 phase construction, which can effectively stabilize the spinel structure by hindering Jahn − Teller distortion. Comprehensive atomic imaging demonstrated that Ni doping can suppress the formation of the unexpected Mn3O4, and rock-salt MnO phases on the surface and subsurface of LiMn2O4 during cycling, which is conducive to stabilizing the MnO6 octahedron and inhibiting the migration of Mn. Resultantly, splendid long cycling stability of 88.92 % after 1000 cycles at 10 C (1 C = 148 mAh g−1) for the optimized LiNi0.05Mn1.95O4 sample is presented. Our study provides an ingenious avenue for regulating the surface optimization and reconstruction of electrode materials.

Preparation of long cycle lifespan spinel LiMn2O4 cathode material by a dual-modified strategy

Spinel LiMn2O4 has been identified as a cathode material with extensive application potential for Li-ion batteries. However, during cycling, the Jahn−Teller effect and Mn dissolution have a substantial impact on its specific capacity and cycle span. Herein, combining Fe and Cr elements co-doping with single crystal truncated octahedron morphology is proposed to solve these problems. The Fe−Cr co-doping markedly restrains the Jahn−Teller effect, and promotes the development of crystal and selective growth of crystal surfaces in spinel LiMn2O4. The high exposure (111) surfaces of the truncated octahedron reduce the dissolution of Mn, and a tiny proportion of (110) and (100) surfaces increase the diffusion channels of Li+. HAADF-STEM characterization indicates that the Fe and Cr elements largely replace the Mn atoms at the octahedral 16d site. Because of these advantages, the optimal LiFe0.05Cr0.08Mn1.95-xO4 (LFCMO-8) delivers excellent electrochemical performance with 119.6 mAh·g−1 discharge capacity and 78.1% capacity retention after 500 cycles at 1 C. At comparatively higher current densities of 20 C and 30 C, the superior capacity retention ratios of 79.8% and 87.3% are still achieved after 2000 cycles. Even at 40 C, the LFCMO-8 sample can still reach 98.8% capacity retention rate after 2000 cycles. After 1000 cycles at 5 C, the LFCMO-8 sample still maintained a capacity retention of 45.4% at high temperature (55 °C). ICP-OES test combined with a V-shaped tube device indicates that the Mn dissolution of LCFMO-8 only accounted for 11.8% of LiFe0.05Mn1.95O4 (LFMO). This study serves as a meaningful reference for the preparation of high-performance LiMn2O4 cathode materials.

A New Spinel Chloride Solid Electrolyte with High Ionic Conductivity and Stability for Na-Ion Batteries

Halide materials are of current interest as solid electrolytes for all-solid-state sodium-ion batteries (ASIBs), due to their good balance between ionic conductivity and electrochemical stability. In this work, by using density functional theory combined with deep potential model and grand potential phase diagram analysis, we report a new spinel chloride (Na2Y2/3Cl4) and systemically evaluate its potential for the solid electrolyte. The spinel Na2Y2/3Cl4 exhibits a high ionic conductivity of 0.94 mS/cm at room temperature and has a three-dimensional isotropic diffusion network comprised of face-sharing octahedra and tetrahedra. Further analysis of the diffusion mechanism indicates that the Na+ conductivity mainly derives from Na ions in the 8a site while the Na ions in the 16d site are mainly used for forming the rhombus skeleton. Besides, the spinel Na2Y2/3Cl4 has a wide electrochemical window of 0.59–3.76 V and good interfacial stability with high-voltage cathodes, which ensures its ability to improve the energy density of ASIBs. This study demonstrates the promising application of the spinel framework in sodium solid electrolytes and sheds new light on developing the halide-based solid electrolyte for ASIBs.

A novel crystallographic location of rattling atoms in filled Eu x Co4Sb12 skutterudites prepared under high-pressure conditions

Abstract Thermoelectric M x Co4Sb12 skutterudites are well-known to exhibit a reduced thermal conductivity thanks to the rattling effect of the M-filler at the large cages occurring in the framework, centered at the 2a sites of the I m 3 ‾ $Im\overline{3}$ space group. A novel Eu-filled skutterudite has been synthesized under high-pressure conditions at 3.5 GPa in a piston-cylinder hydrostatic press. The structural refinement from high-angular resolution synchrotron X-ray diffraction (SXRD) patterns unveils an unusual position for Eu filler atoms. By difference Fourier synthesis they are found at 12d sites, conforming statistically occupied octahedra within the mentioned cages around 2a positions. The Debye temperature was estimated by averaging the isotropic displacements by the atomic masses, leading to θ D ${\theta }_{D}$ of 273(2) K. Oftedal plots concerning the y and z Sb fractional positions, the unit-cell parameter a and M filling fraction include the novel Eu specimen in the trend observed for other filled materials prepared under high-pressure, including rare-earths, alkali or alkali-earth elements, all accepted as rattlers in filled skutterudites. A total thermal conductivity (κ) of 0.82 W m−1 K−1 is measured at 773 K for Eu0.02(1)Co4Sb12, below that of other filled skutterudites, which is promoted by the enhanced phonon scattering of Eu located at 12d sites. FE-SEM images showed large, homogeneous grains, well compacted after the high-pressure synthesis.

Realization of superior ionic conductivity by manipulating the atomic rearrangement in Al-doped Li7La3Zr2O12

High ionic conductivity is usually observed in the cubic phase of garnet Li7La3Zr2O12 (LLZO), which can be stabilized by dopants including Ca2+, Fe3+, Al3+, Ga3+, Ti4+, and Si4+. However, the ionic conductivity shows a strong dependence on both the lithium and the dopant atomic occupancy of the garnet LLZO crystal structure (space group Ia 3‾ d), i.e., the 24d (LiO4) or 96 h (LiO6) sites. Dopants occupying the 24d site can induce a strong local electric field which blocks the Li+ diffusion path. The sparking plasma sintering (SPS) process, which limits the diffusion and relaxation time of the material, introduces a metastable state of the cubic LLZO with strong lattice distortion and inadequate ion distribution. Post-annealing promotes ion rearrangement, especially the Al3+ migration from the 24d to 96 h sites, which is driven by the mitigation of the metastable state as identified by structure and composition analysis. Ionic conductivity as high as 3.3 × 10−4 S cm−1 is achieved along with low electronic conductivity of 5.17 × 10−7 S cm−1 by post-annealing at 500 °C in an oxygen environment after the SPS process, meanwhile, the activation energy of is SPS500 as low as 0.36 eV, representing the low energy barriers for ion transportation. This work demonstrated a strategy to fabricate LLZO solid-state electrolyte with high ionic conductivity by manipulating its metastable state and reveal atomic occupation is a vital factor in influencing ionic conductivity besides doping content and bulk density.

Determination of exchange integrals and effect of cationic site occupancy (8b/24d) on the structural and magnetic properties of nanocrystalline Mn-doped Gd2O3

Mn doped Gd2(1‐x)Mn2xO3 (x = 0.03, 0.05) nanoparticles were prepared by simple co-precipitation method. The distribution of the cations in the six coordinated 8b and 24d sites were determined from Rietveld analysis. In addition, the cation-anion-cation bonds length which are responsible for the super-exchange interaction was extracted to describe the magnetic interaction in the samples. Transmission electron microscopy (TEM) and Raman spectroscopy were employed to investigate the microstructure and presence of any impurity (if any) phase of the samples. X-ray photoelectron spectroscopy (XPS) reveals the decrease in the number of Gd-O bonding and a corresponding increase in Mn-O bonding due to the successful replacement of Gd ions by Mn ions as the concentration increases. The first (nearest neighbor) and second exchange integral (next to nearest neighbor) were determined from molecular field model and the values confirm the occurrence of the antiferromagnetic interaction in the samples. The anomalies in the 1χ vs. T data and non-linearity in M-H curve at 5 K were successfully interpreted by the cationic distribution in different local symmetry sites.

Determination of the site preference on the structure, magnetism and mechanical anisotropy properties of Mo-containing alloy carbide M6C (M = Fe, Mo)

First-principles calculations are used to study the structure, magnetism and mechanical anisotropy properties of M6C (M = Fe, Mo) carbides. The stability of alloy carbide M6C can be improved when Mo atoms occupy the 48f Wyckoff position. Fe3Mo3C with Mo atoms occupying 48f position and Fe atoms occupying 16d and 32e positions has the best structural stability. The magnetic moment is triggered when the Fe content is approximately 0.5, suggesting that there exists a critical value between the paramagnetic nature and ferromagnetism. Carbides with Fe content above 0.5 have stronger magnetism. Higher Fe content corresponds to the stronger chemical bonding of carbides, resulting in improved elastic properties when Mo atoms are held in 48f position. The special carbides Fe4Mo2C and Fe3Mo3C (Fe at 48f site, Mo at 16d and 32e sites) correspond to the excellent mechanical properties. These results are helpful in providing a theoretical foundation of the possible direction for the advances of the excellent physical properties in Mo-containing steel.

Characterization of imperfections in scintillator crystals using gamma-ray induced positron annihilation lifetime spectroscopy

Gamma-ray-induced positron annihilation lifetime spectroscopy (GiPALS) was used to characterize pristine and codoped Lu3Al5O12 (LuAG) crystals grown using Czochralski (Cz) and micropulling-down (mPD) methods. GiPALS spectra were analyzed using a two-state trapping model. The bulk and defect lifetimes were theoretically calculated based on density functional theory (DFT) using the projector-augmented-wave (PAW) method. The experimentally measured and theoretically calculated bulk lifetimes almost agreed, thereby validating the experiment and simulation. The defect lifetimes almost coincided with positron annihilation lifetimes due to Al monovacancy at the 24d and 16a sites. Li+ and Mg2+ codoping weakened the vacancy-related component, indicating that codoping had effectively reduced the concentration of Al monovacancy. The Ce 5d–4f thermoluminescence (TL) glow curve revealed that Mg2+ codoping had annihilated the trapped electron centers. In contrast, Li+ codoping increased the concentration of interstitial Li+ ion associated trapped electron centers. Ce-L3 X-ray absorption near-edge structure (XANES) spectra demonstrated that Ce4+ ions at the 24c site had compensated for Mg2+ ion charges at the 24d and 16a site. The Ce4+ ions and oxygen vacancies were supposed to compensate for Li+ ion charges at the 24d and 16a sites.

Simultaneously Improved Cubic Phase Stability and Li-Ion Conductivity in Garnet-Type Solid Electrolytes Enabled by Controlling the Al Occupation Sites.

Here, we, for the first time, report on the simultaneous enhancement in cubic phase stability and Li-ion conductivity of garnet-type solid electrolytes (SEs) by adding excess Li/Al. The excess Al/Li creates very large grains of up to 170 μm via the segregation of Al at the grain boundaries and enables preferential Al occupation at 96h sites over 24d sites, a behavior contrary to previous observations. The resulting SE shows improved Li-ion conductivity due to the large grain size and less blocking Li pathway caused by different preferential Al occupation. Surprisingly, it is observed that the cubic phase of the garnet-type SE is transformed to the tetragonal phase on the surface and in the bulk under the applied voltage, and the preferential Al occupation enables its cubic phase stability. Under battery operating conditions, the LLZO SE with excess Li/Al can maintain high ionic conductivity due to the cubic phase stability and large grain size. We clearly demonstrate that the cubic phase stability and ionic conductivity of LLZO can be simultaneously improved by excess Li/Al without any post-treatments. The findings and understanding will provide new insights into practical use of the garnet-type SEs for advanced all solid-state batteries.

Li sublattice and diffusive response to uniaxial loads in the solid electrolyte, Li[formula omitted]La[formula omitted]Zr[formula omitted]O12 (LLZO)

The polymorphism of the garnet solid electrolyte, Li7La3Zr2O12 (LLZO), is a critical facet of the material’s performance and viability as an electrolyte candidate. Indeed, the cubic polymorph has an ionic conductivity several orders of magnitude higher than the tetragonal polymorph. While the transition from tetragonal to cubic LLZO has been reported over a range of temperatures, the response of the material to asymmetrical mechanical loads is not fully understood. To fill the knowledge gap, this paper conducted classical molecular dynamics (MD) simulations to investigate the diffusive response of LLZO under uniaxial stress conditions at 1000 K. It is found that the transition from cubic to tetragonal LLZO occurs around 500 MPa in compression and 750 MPa in tension. Near these threshold stresses, the Li sublattice undergoes a smooth transition from a cubic-like arrangement of interstitial occupancies to a tetragonal-like arrangement, with the occupancies of 24d and 96h interstitial sites decreasing and increasing respectively as the stress increases. The activation energy for diffusion increases with both tension and compression, increasing at a rate of 39 × 10−6 and 7 × 10−6 eV/MPa in compression and tension respectively.

Crystal structure of the τ11 Al4Fe1.7Si phase from neutron diffraction and ab initio calculations

The intermetallic τ11 Al4Fe1.7Si phase is of interest for high-temperature structural application due to its combination of low density and high strength. We determine the crystal structure of the τ11 phase through a combination of powder neutron diffraction and density functional theory calculations. Using Pawley and Rietveld refinements of the neutron diffraction data provides an initial crystal structure model. Since Al and Si have nearly identical neutron scattering lengths, we use density-functional calculations to determine their preferred site occupations. The τ11 phase exhibits a hexagonal crystal structure with space group P63/mmc and lattice parameters of a = 7.478 Å and c = 7.472 Å. The structure comprises five Wyckoff positions; Al occupies the 6h and 12k sites, Fe the 2a and 6h sites, and Si the 2a sites. We observe site disorder and partial occupancies on all sites with a large fraction of 80% Fe vacancies on the 2d sites, indicating an entropic stabilization of the τ11 phase at high temperature.

Y2O3:Eu and the Mössbauer isomer shift coefficient of Eu compounds from ab-initio simulations

We report on a full potential density functional theory characterization of Y2O3 upon Eu doping on the two inequivalent crystallographic sites 24d and 8b. We analyze local structural relaxation, electronic properties and the relative stability of the two sites. The simulations are used to extract the contact charge density at the Eu nucleus. Then we construct the experimental isomer shift (IS) versus contact charge density calibration curve, by considering an ample set of Eu compounds: EuF3, EuO, EuF2, EuS, EuSe, EuTe, EuPd3 and the Eu metal. The, expected, linear dependence has a slope of α = 0.054 mm s−1 Å− 3, which corresponds to nuclear expansion parameter ΔR/R = 6.0 × 10−5. α allows to obtain an unbiased and accurate estimation of the IS for any Eu compound. We test this approach on two mixed-valence compounds Eu3S4 and Eu2SiN3, and use it to predict the Y2O3:Eu IS with the result +1.04 mm s−1 at the 24d site and +1.00 mm s−1 at the 8b site.

Magnetic properties and electronic structure of Mn-Al alloys in the β-Mn structure

In this work, the electronic structure and magnetic properties of the Mn-Al alloys with different Mn and Al concentrations in the β-Mn-type structure have been theoretically investigated. The structural stability of different types of aluminum and manganese atoms occupations of the 12d and 8c site positions are compared. For the Mn3Al with 5Al in the 12d positions we obtained the most energetically preferable arrangement of Mn and Al ions in this alloy. Further occupation of this type of position by the Al atoms might be responsible for the lower effective magnetic moment estimated from the experimental data. Our theoretical calculations demonstrate the complex character of the magnetic properties and electronic structure of the Mn-Al alloys.

Structure of boehmite-derived γ-alumina and its transformation mechanism revealed by electron crystallography

γ-Alumina is a widely used material, while its precise crystal structure and transformation mechanism derived from boehmite have remained unclear in the literature for decades. In this work, quantitative electron microscopy has been applied to study the crystalline structure of γ-alumina and its transformation mechanism from boehmite. Based on Rietveld refinement of electron diffraction patterns, a new tetragonal structure model, with a space group of I41/amd (No. 141), was proposed for the γ-alumina phase, with Al cations on 4a, 8c, 8d and 16g sites and O anions on the 16h site, which could provide better fits than current models. During the boehmite to γ-alumina transformation induced by e-beam irradiation, when the boehmite layers were oriented along the edge-on direction, a shrinkage caused by dehydration was directly observed. Two kinds of boehmite to γ-alumina transformation mechanisms, namely collapse and reaction mechanisms, were elucidated crystallographically in detail with new insights through an intermediate structure, and the reaction mechanism was demonstrated to produce much reduced changes in dimensions and volume, compared with the collapse mechanism. The experimental observations supported the reaction mechanism, which occurred through partial occupation of the dehydrated space by diffusion in the initial stage of the transformation, without the formation of voids that only appeared after the initial stage. Filling tetrahedral interstices of the intermediate structure with Al cations in different ways yields tetragonal or cubic γ-alumina structures, and the tetragonal structure is energetically favorable because of smaller lattice distortions required, compared with the cubic structure. The crystallographic orientation relationships of γ-alumina with the parent boehmite phase deduced from the proposed mechanisms are consistent with the experimental observations.

Crystallographic-Site-Specific Structural Engineering Enables Extraordinary Electrochemical Performance of High-Voltage LiNi0.5 Mn1.5 O4 Spinel Cathodes for Lithium-Ion Batteries.

The development of reliable and safe high-energy-density lithium-ion batteries is hindered by the structural instability of cathode materials during cycling, arising as a result of detrimental phase transformations occurring at high operating voltages alongside the loss of active materials induced by transition metal dissolution. Originating from the fundamental structure/function relation of battery materials, the authors purposefully perform crystallographic-site-specific structural engineering on electrode material structure, using the high-voltage LiNi0.5 Mn1.5 O4 (LNMO) cathode as a representative, which directly addresses the root source of structural instability of the Fd m structure. By employing Sb as a dopant to modify the specific issue-involved 16c and 16d sites simultaneously, the authors successfully transform the detrimental two-phase reaction occurring at high-voltage into a preferential solid-solution reaction and significantly suppress the loss of Mn from the LNMO structure. The modified LNMO material delivers an impressive 99% of its theoretical specific capacity at 1 C, and maintains 87.6% and 72.4% of initial capacity after 1500 and 3000 cycles, respectively. The issue-tracing site-specific structural tailoring demonstrated for this material will facilitate the rapid development of high-energy-density materials for lithium-ion batteries.

Review of the influence of copper and chromium substitution on crystal structure, magnetic properties and magnetocaloric effect of GdFe2−x(Cu, Cr)x (x = 0, 0.1, 0.15 and 0.2) intermetallic compounds

The iron-based compounds GdFe2−x(Cu,Cr)x (x = 0, 0.1, 0.15 and 0.2) were synthesized successfully by means of arc-melting and annealing at 800 °C for one week. The structural, magnetic and magnetocaloric properties of these intermetallic compounds were investigated systematically in detail using X-ray powder diffraction (XRD) analysis, Scanning electron microscopy (SEM) equipped with Energy dispersive X-ray spectroscopy (EDS), and magnetic measurements. The Rietveld analysis of X-ray diffraction patterns proves that GdFe2−x(Cu,Cr)x (x = 0, 0.1, 0.15 and 0.2) compounds crystallize in the cubic laves phase MgCu2-type structure with the Fd3̄m space group. Gadolinium and iron atoms statistically occupy the 8a and 16d sites respectively. Moreover, copper and chromium atoms substitute the iron atoms at site 8a in the MgCu2-type structure. The temperature dependence of magnetization studied in a broad temperature range reveals that all compounds exhibit a ferromagnetic-paramagnetic transition at Curie temperature (TC). We find that the substitution of iron by copper and chromium leads to a decrease in the magnetic ordering transition temperature. The Arrott plots of all our samples show the occurrence of a second-order phase transition. Besides, the performance of magnetocaloric effect (MCE) for GdFe2−x(Cu,Cr)x (x = 0, 0.1, 0.15 and 0.2) compounds was evaluated by the magnetic entropy change (ΔSM) and the related Relative Cooling Power (RCP). In the vicinity of TC, the ΔSM reached a maximum value of 0.79 J/kg.K, 1.2 J/kg.K, 1.4 J/kg.K and 2.5 J/kg.K, while the RCP was found to be 13.2 J/kg, 21.6 J/kg, 31.7 J/kg and 44.3 J/kg, respectively for GdFe2−xCux (x = 0, 0.1, 0.15 and 0.2) compounds. Furthermore, the GdFe2−xCrx (x = 0.1, 0.15 and 2) compounds show ΔSM values of about 0.9 J/kg.K, 1.3 J/kg.K and 1.8 J/kg.K, and RCP values of 14.8 J/kg, 25.4 J/kg and 36.8 J/kg respectively, under a field change of 1.56 T. Through these results, the GdFe2−x(Cu,Cr)x (x = 0, 0.1, 0.15 and 0.2) compounds can be an attractive materials for use in magnetic refrigeration and heat pumping technology above room temperature.

Cation distribution and bond energy of intermediate spinel Mg(Zn0.5Ti0.5)2xGa(2−2x)O4 microwave dielectric ceramics

Substitution of Ga3+ by [Zn0.5Ti0.5]3+ in MgGa2O4 improved the comprehensive properties of the resultant spinel. A continuous solid solution with a spinel structure was formed in Mg(Zn0.5Ti0.5)2xGa(2−2x)O4 (0 ≤ x ≤ 1); here, Zn2+ occupied the tetrahedral 8a site while Ti4+ occupied the octahedral 16d site, resulting in a decrease in the degree of inversion λ from 0.86 to 0. The optimal sintering temperature decreased from 1460 °C to 1220 °C, and the dielectric constant (εr) increased from 8.8 to 14.9; these changes could be ascribed to the greater polarizability of [Zn0.5Ti0.5]3+ relative to that of Ga3+. The temperature coefficient of resonant frequency (τf) of the material remarkably increased from −64.1 ppm/°C to −16.8 ppm/°C, which may be attributed to the increase in dielectric polarizability/molecular volume, bond energy, and bond valence in B-sites. The high-quality factor (Q × f) slightly decreased from 89,253 GHz to 73,432 GHz with decreasing λ and packing fraction. Optimal microwave dielectric properties were obtained from the sample with x = 1 and sample sintered at 1220 °C; in this case, εr = 14.9, Q × f = 73,432 GHz, and τf = −16.8 ppm/°C.

Effects of Ti substitution for Zr on the electrochemical characteristics and structure of AB2-type Laves-phase alloys as metal hydride anodes

The structural composition and electrochemical capacity of four AB2 Laves-type intermetallic alloys with various Ti/Zr ratios (TixZr1−xLa0.03Ni1.2Mn0.7V0.12Fe0.12, x = 0.12, 0.15, 0.18, and 0.22) were investigated in this study. The alloys were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. These data revealed the coexistence of the main phase of the C15-type FCC Laves-type AB2 compounds with a secondary La–Ni intermetallic that was present in minor amounts. Increasing the Ti substitution for Zr caused the gradual shrinkage of the unit cells of the C15 phase. The neutron powder diffraction studies demonstrated that in the trihydride (Ti, Zr, V)(Ni, Mn, Fe, V)2D3.2, D atoms filled A2B2 tetrahedra, whereas V atoms occupied not only conventional 16d sites but also partially replaced Zr/Ti at 8a sites. All studied alloys showed similar activation behaviors, wherein four cycles were required to realize the highest electrochemical capacity of the anodes. The Ti12/Zr88 alloy demonstrated excellent full discharge capacity that reached 466 mAh/g. The Ti22/Zr78 alloy electrode exhibited good cycling stability (retention rate of ~71%) after 500 cycles and a superior high-rate discharge capability (retention rate of ~71%) at a discharge current density of 400 mA/g. The cycling of the Ti22/Zr78 alloy electrode was studied by electrochemical impedance spectroscopy (EIS) to understand the reasons for the deterioration of cycling capacity, which was related with the pulverization of the alloys and increase in irreversible capacity.