Molecules

Research

Jump to: Review

19 pages, 4802 KiB

Open AccessArticle

The Effect of Y Content on Structural and Sorption Properties of A₂B₇-Type Phase in the La–Y–Ni–Al–Mn System

by Emil H. Jensen, Loris Lombardo, Alessandro Girella, Matylda N. Guzik, Andreas Züttel, Chiara Milanese, Pamela Whitfield, Dag Noréus and Sabrina Sartori

Molecules 2023, 28(9), 3749; https://doi.org/10.3390/molecules28093749 - 27 Apr 2023

Cited by 3 | Viewed by 1519

Abstract

Metal hydrides are an interesting group of chemical compounds, able to store hydrogen in a reversible, compact and safe manner. Among them, A₂B₇-type intermetallic alloys based on La-Mg-Ni have attracted particular attention due to their high electrochemical hydrogen storage [...] Read more.

Metal hydrides are an interesting group of chemical compounds, able to store hydrogen in a reversible, compact and safe manner. Among them, A₂B₇-type intermetallic alloys based on La-Mg-Ni have attracted particular attention due to their high electrochemical hydrogen storage capacity (∼400 mAh/g) and extended cycle life. However, the presence of Mg makes their synthesis via conventional metallurgical routes challenging. Replacing Mg with Y is a viable approach. Herein, we present a systematic study for a series of compounds with a nominal composition of La_2-xY_xNi_6.50Mn_0.33Al_0.17, x = 0.33, 0.67, 1.00, 1.33, 1.67, focusing on the relationship between the material structural properties and hydrogen sorption performances. The results show that while the hydrogen-induced phase amorphization occurs in the Y-poor samples (x < 1.00) already during the first hydrogen absorption, a higher Y content helps to maintain the material crystallinity during the hydrogenation cycles and increases its H-storage capacity (1.37 wt.% for x = 1.00 vs. 1.60 wt.% for x = 1.67 at 50 °C). Thermal conductivity experiments on the studied compositions indicate the importance of thermal transfer between powder individual particles and/or a measuring instrument. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

12 pages, 979 KiB

Open AccessArticle

Core-Shell, Critical-Temperature-Suppressed V Alloy-Pd Alloy Hydrides for Hydrogen Storage—A Technical Evaluation

by Krystina E. Lamb and Colin J. Webb

Molecules 2023, 28(7), 3024; https://doi.org/10.3390/molecules28073024 - 28 Mar 2023

Cited by 2 | Viewed by 1782

Abstract

Hydrogen storage for energy applications is of significant interest to researchers seeking to enable a transition to lower-pollution energy systems. Two of the key drawbacks of using hydrogen for energy storage are the low gas-phase storage density and the high energy cost of [...] Read more.

Hydrogen storage for energy applications is of significant interest to researchers seeking to enable a transition to lower-pollution energy systems. Two of the key drawbacks of using hydrogen for energy storage are the low gas-phase storage density and the high energy cost of the gas-phase compression. Metal hydride materials have the potential to increase hydrogen storage density and decrease the energy cost of compression by storing the hydrogen as a solid solution. In this article, the technical viability of core-shell V₉₀Al₁₀-Pd₈₀Ag₂₀ as a hydrogen storage material is discussed. LaNi₅, LaNi₅/acrylonitrile-butadiene-styrene copolymer mixtures, core-shell V-Pd, and core-shell V₉₀Al₁₀-Pd₈₀Ag₂₀ are directly compared in terms of reversible hydrogen-storage content by weight and volume. The kinetic information for each of the materials is also compared; however, this work highlights missing information that would enable computational dynamics modelling. Results of this technical evaluation show that V₉₀Al₁₀-Pd₈₀Ag₂₀ has the potential to increase gravimetric and volumetric hydrogen capacity by 1.4 times compared to LaNi₅/acrylonitrile-butadiene-styrene copolymer mixtures. In addition, the literature shows that Pd₈₀Ag₂₀ and V₉₀Al₁₀ both have similarly good hydrogen permeabilities, thermal conductivities, and specific heats. In summary, this evaluation demonstrates that core-shell V₉₀Al₁₀-Pd₈₀Ag₂₀ could be an excellent, less-expensive hydrogen storage material with the advantages of improved storage capacity, handleability, and safety compared to current AB₅-polymer mixtures. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

12 pages, 2491 KiB

Open AccessArticle

Hydrogen Absorption Reactions of Hydrogen Storage Alloy LaNi₅ under High Pressure

by Toyoto Sato, Hiroyuki Saitoh, Reina Utsumi, Junya Ito, Yuki Nakahira, Kazuki Obana, Shigeyuki Takagi and Shin-ichi Orimo

Molecules 2023, 28(3), 1256; https://doi.org/10.3390/molecules28031256 - 27 Jan 2023

Cited by 13 | Viewed by 3687

Abstract

Hydrogen can be stored in the interstitial sites of the lattices of intermetallic compounds. To date, intermetallic compound LaNi₅ or related LaNi₅-based alloys are known to be practical hydrogen storage materials owing to their higher volumetric hydrogen densities, making them [...] Read more.

Hydrogen can be stored in the interstitial sites of the lattices of intermetallic compounds. To date, intermetallic compound LaNi₅ or related LaNi₅-based alloys are known to be practical hydrogen storage materials owing to their higher volumetric hydrogen densities, making them a compact hydrogen storage method and allowing stable reversible hydrogen absorption and desorption reactions to take place at room temperature below 1.0 MPa. By contrast, gravimetric hydrogen density is required for key improvements (e.g., gravimetric hydrogen density of LaNi₅: 1.38 mass%). Although hydrogen storage materials have typically been evaluated for their hydrogen storage properties below 10 MPa, reactions between hydrogen and materials can be facilitated above 1 GPa because the chemical potential of hydrogen dramatically increases at a higher pressure. This indicates that high-pressure experiments above 1 GPa could clarify the latent hydrogen absorption reactions below 10 MPa and potentially explore new hydride phases. In this study, we investigated the hydrogen absorption reaction of LaNi₅ above 1 GPa at room temperature to understand their potential hydrogen storage capacities. The high-pressure experiments on LaNi₅ with and without an internal hydrogen source (BH₃NH₃) were performed using a multi-anvil-type high-pressure apparatus, and the reactions were observed using in situ synchrotron radiation X-ray diffraction with an energy dispersive method. The results showed that 2.07 mass% hydrogen was absorbed by LaNi₅ at 6 GPa. Considering the unit cell volume expansion, the estimated hydrogen storage capacity could be 1.5 times higher than that obtained from hydrogen absorption reaction below 1.0 MPa at 303 K. Thus, 33% of the available interstitial sites in LaNi₅ remained unoccupied by hydrogen atoms under conventional conditions. Although the hydrogen-absorbed LaNi₅H_x (x < 9) was maintained below 573 K at 10 GPa, LaNi₅H_x began decomposing into NiH, and the formation of a new phase was observed at 873 K and 10 GPa. The new phase was indexed to a hexagonal or trigonal unit cell with a ≈ 4.44 Å and c ≈ 8.44 Å. Further, the newly-formed phase was speculated to be a new hydride phase because the Bragg peak positions and unit cell parameters were inconsistent with those reported for the La-Ni intermetallic compounds and La-Ni hydride phases. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

12 pages, 3356 KiB

Open AccessArticle

Hydrogen and Deuterium Solubility, Diffusivity and Permeability from Sorption Measurements in the Ni₃₃Ti₃₉Nb₂₈ Alloy

by Oriele Palumbo, Francesco Trequattrini, Silvano Tosti, Alessia Santucci and Annalisa Paolone

Molecules 2023, 28(3), 1082; https://doi.org/10.3390/molecules28031082 - 21 Jan 2023

Viewed by 1198

Abstract

The hydrogen/deuterium sorption properties of Ni₃₃Ti₃₉Nb₂₈ synthesized by the vacuum induction melting technique were measured between 400 and 495 °C for pressure lower than 3 bar. The Sieverts law is valid up to H(D)/M < 0.2 in its [...] Read more.

The hydrogen/deuterium sorption properties of Ni₃₃Ti₃₉Nb₂₈ synthesized by the vacuum induction melting technique were measured between 400 and 495 °C for pressure lower than 3 bar. The Sieverts law is valid up to H(D)/M < 0.2 in its ideal form; the absolute values of the hydrogenation/deuteration enthalpy are ΔH(H₂) = 85 ± 5 kJ/mol and ΔH(D₂) = 84 ± 4 kJ/mol. From the kinetics of absorption, the diffusion coefficient was derived, and an Arrhenius dependence from the temperature was obtained, with E_a,d = 12 ± 1 kJ/mol for both hydrogen isotopes. The values of the alloy permeability, obtained by combining the solubility and the diffusion coefficient, were of the order of 10⁻⁹ mol m⁻¹ s⁻¹ Pa^−0.5, a value which is one order of magnitude lower than that of Ni₄₁Ti₄₂Nb₁₇, until now the best Ni-Ti-Nb alloy for hydrogen purification. In view of the simplicity of the technique here proposed to calculate the permeability, this method could be used for the preliminary screening of new alloys. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

21 pages, 17894 KiB

Open AccessArticle

Evaluation of Hydrogen Gettering Rates Correlated to Surface Composition and Texture of Nickel-Plated Zircaloy Getters of Different Heat Treatment Procedures

by Ewa C. E. Rönnebro, Mark Engelhard, Danny Edwards, Katarzyna Grubel, Anthony Guzman and Randall Storms

Molecules 2023, 28(2), 762; https://doi.org/10.3390/molecules28020762 - 12 Jan 2023

Viewed by 1496

Abstract

Coatings of metal specimens are known to have an impact on hydrogen gettering (hydrogen absorption). The coating can have one or more functions, such as enhancing gettering, preventing gettering and/or preventing oxidation of the metal substrate. It is known that contaminants and surface [...] Read more.

Coatings of metal specimens are known to have an impact on hydrogen gettering (hydrogen absorption). The coating can have one or more functions, such as enhancing gettering, preventing gettering and/or preventing oxidation of the metal substrate. It is known that contaminants and surface texture can impact hydrogen gettering/absorption performance, but has not previously been thoroughly explored. This study evaluated the role of different post-plating heat treatments of nickel-plated zircaloy-4 getters (NPGs) and the role of the heat treatments on gettering rates, surface composition and texture. Nickel plating is applied to prevent oxidation of the Zircaloy-4 surface and also enhances gettering. The nickel plating must be heat treated before desirable gettering can occur. Our NPG getters with historically known satisfying performance were pre-heat treated in air followed by activation heat treatment in a vacuum at a higher temperature. In this study, we were interested in finding out if both heat treatment steps were necessary to obtain a desirable gettering performance, or if one step could be omitted. XPS analysis showed that if the nickel surface is not heat treated before bonding the nickel to the zirconium in the activation step, there will be carbon contaminants on the surface, which significantly reduces gettering. We studied the texture of Zircaloy-4 using SEM/EBSD to compare NPGs with both heat treatment steps with NPGs that had no post-plating heat treatment to learn if the degree of cold work could be impacted by the heat treatment steps. We did not observe any differences in texture between them. We measured gettering rates of both pretreated and activated NPGs and NPGs that had been activated without first being pre-heat treated. We found that the NPGs without the first post-plating heating step had up to a seven times slower gettering rate and obtained higher plateau pressures due to the contaminated surface. Thus, the pre-heat treatment in air before activation is necessary to avoid slower gettering rates and higher plateau pressures. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

18 pages, 7031 KiB

Open AccessArticle

Deuterium Distribution in Fe/V Multi-Layered Films

by Ryota Gemma, Talaat Al-Kassab and Astrid Pundt

Molecules 2022, 27(22), 7848; https://doi.org/10.3390/molecules27227848 - 14 Nov 2022

Viewed by 1602

Abstract

The recent progress of Atom Probe Tomography (APT) has opened up atomic-scale elemental analysis including hydrogen species. For APT measurements, the use of deuterium is highly recommended, due to its low mobility compared to the fast and quantum mechanically tunneling isotope hydrogen. In [...] Read more.

The recent progress of Atom Probe Tomography (APT) has opened up atomic-scale elemental analysis including hydrogen species. For APT measurements, the use of deuterium is highly recommended, due to its low mobility compared to the fast and quantum mechanically tunneling isotope hydrogen. In addition, deuterium can be distinguished from hydrogen originating from the APT analysis chamber. To date, however, APT studies on materials with high D concentrations are scarce. In this study, the D concentration profile in a Fe/V multi-layered film sample was investigated, and spanned a wide concentration range. The mean hydrogen isotope concentration was alternatively quantified by electromotive force (EMF) measurements on a similar Fe/V film, thus verifying the APT results. The reduction found in the D concentration at the Fe/V interface results from local alloying at the Fe/V interfaces which accompanies a change in the available volume in the V lattice. Even at the same Fe concentration, the shape of the observed D depth profile was asymmetric at high D₂ pressures. This indicates a stress impact caused by the deposition sequence. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

15 pages, 3473 KiB

Open AccessArticle

Transformation Kinetics of LiBH₄–MgH₂ for Hydrogen Storage

by Ou Jin, Yuanyuan Shang, Xiaohui Huang, Dorothée Vinga Szabó, Thi Thu Le, Stefan Wagner, Thomas Klassen, Christian Kübel, Claudio Pistidda and Astrid Pundt

Molecules 2022, 27(20), 7005; https://doi.org/10.3390/molecules27207005 - 18 Oct 2022

Cited by 8 | Viewed by 1794

Abstract

The reactive hydride composite (RHC) LiBH₄–MgH₂ is regarded as one of the most promising materials for hydrogen storage. Its extensive application is so far limited by its poor dehydrogenation kinetics, due to the hampered nucleation and growth process of MgB [...] Read more.

The reactive hydride composite (RHC) LiBH₄–MgH₂ is regarded as one of the most promising materials for hydrogen storage. Its extensive application is so far limited by its poor dehydrogenation kinetics, due to the hampered nucleation and growth process of MgB₂. Nevertheless, the poor kinetics can be improved by additives. This work studied the growth process of MgB₂ with varying contents of 3TiCl₃·AlCl₃ as an additive, and combined kinetic measurements, X-ray diffraction (XRD), and advanced transmission electron microscopy (TEM) to develop a structural understanding. It was found that the formation of MgB₂ preferentially occurs on TiB₂ nanoparticles. The major reason for this is that the elastic strain energy density can be reduced to ~4.7 × 10⁷ J/m³ by creating an interface between MgB₂ and TiB₂, as opposed to ~2.9 × 10⁸ J/m³ at the original interface between MgB₂ and Mg. The kinetics of the MgB₂ growth was modeled by the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation, describing the kinetics better than other kinetic models. It is suggested that the MgB₂ growth rate-controlling step is changed from interface- to diffusion-controlled when the nucleation center changes from Mg to TiB₂. This transition is also reflected in the change of the MgB₂ morphology from bar- to platelet-like. Based on our observations, we suggest that an additive content between 2.5 and 5 mol% 3TiCl₃·AlCl₃ results in the best enhancement of the dehydrogenation kinetics. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

21 pages, 5698 KiB

Open AccessArticle

From Iron to Copper: The Effect of Transition Metal Catalysts on the Hydrogen Storage Properties of Nanoconfined LiBH₄ in a Graphene-Rich N-Doped Matrix

by Alejandra A. Martínez, Aurelien Gasnier and Fabiana C. Gennari

Molecules 2022, 27(9), 2921; https://doi.org/10.3390/molecules27092921 - 3 May 2022

Cited by 4 | Viewed by 1881

Abstract

Incipient wetness impregnation was employed to decorate two N-doped graphene-rich matrixes with iron, nickel, cobalt, and copper nanoparticles. The N-doped matrix was wetted with methanol solutions of the corresponding nitrates. After agitation and solvent evaporation, reduction at 800 °C over the carbon matrix [...] Read more.

Incipient wetness impregnation was employed to decorate two N-doped graphene-rich matrixes with iron, nickel, cobalt, and copper nanoparticles. The N-doped matrix was wetted with methanol solutions of the corresponding nitrates. After agitation and solvent evaporation, reduction at 800 °C over the carbon matrix promoted the formation of nanoparticles. The mass of the metal fraction was limited to 5 wt. % to determine if limited quantities of metallic nanoparticles catalyze the hydrogen capture/release of nanoconfined LiBH₄. Isotherms of nitrogen adsorption afforded the textural characterization of the matrixes. Electronic microscopy displayed particles of definite size, evenly distributed on the matrixes, as confirmed by X-ray diffraction. The same techniques assessed the impact of LiBH₄ 50 vol. % impregnation on nanoparticle distribution and size. The hydrogen storage properties of these materials were evaluated by differential scanning calorimetry and two cycles of volumetric studies. X-ray diffraction allowed us to follow the evolution of the material after two cycles of hydrogen capture-release. We discuss if limited quantities of coordination metals can improve the hydrogen storage properties of nanoconfined LiBH₄, and which critical parameters might restrain the synergies between nanoconfinement and the presence of metal catalysts. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Graphical abstract

12 pages, 1375 KiB

Open AccessArticle

Effects of LiBF₄ Addition on the Lithium-Ion Conductivity of LiBH₄

by Laura M. de Kort, Valerio Gulino, Didier Blanchard and Peter Ngene

Molecules 2022, 27(7), 2187; https://doi.org/10.3390/molecules27072187 - 28 Mar 2022

Cited by 7 | Viewed by 2756

Abstract

Complex hydrides, such as LiBH₄, are a promising class of ion conductors for all-solid-state batteries, but their application is constrained by low ion mobility at room temperature. Mixing with halides or complex hydride anions, i.e., other complex hydrides, is an effective [...] Read more.

Complex hydrides, such as LiBH₄, are a promising class of ion conductors for all-solid-state batteries, but their application is constrained by low ion mobility at room temperature. Mixing with halides or complex hydride anions, i.e., other complex hydrides, is an effective approach to improving the ionic conductivity. In the present study, we report on the reaction of LiBH₄ with LiBF₄, resulting in the formation of conductive composites consisting of LiBH₄, LiF and lithium closo-borates. It is believed that the in-situ formation of closo-borate related species gives rise to highly conductive interfaces in the decomposed LiBH₄ matrix. As a result, the ionic conductivity is improved by orders of magnitude with respect to the Li-ion conductivity of the LiBH₄, up to 0.9 × 10⁻⁵ S cm⁻¹ at 30 °C. The insights gained in this work show that the incorporation of a second compound is a versatile method to improve the ionic conductivity of complex metal hydrides, opening novel synthesis pathways not limited to conventional substituents. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Figure 1

14 pages, 2736 KiB

Open AccessArticle

Microstructure and First Hydrogenation Properties of TiHfZrNb_1−xV_1+x Alloy for x = 0, 0.1, 0.2, 0.4, 0.6 and 1

by Salma Sleiman and Jacques Huot

Molecules 2022, 27(3), 1054; https://doi.org/10.3390/molecules27031054 - 4 Feb 2022

Cited by 9 | Viewed by 1654

Abstract

The effect of the substitution of Nb by V on the microstructure and hydrogen storage properties of TiHfZrNb_1−xV_1+x alloys (x = 0.1, 0.2, 0.4, 0.6 and 1) was investigated. For x = 0, the alloy was pure BCC and upon [...] Read more.

The effect of the substitution of Nb by V on the microstructure and hydrogen storage properties of TiHfZrNb_1−xV_1+x alloys (x = 0.1, 0.2, 0.4, 0.6 and 1) was investigated. For x = 0, the alloy was pure BCC and upon the substitution of niobium by vanadium, the BCC was progressively replaced by HCP and FCC phases. For x = 0.6, a C15 phase was also present and becomes the main phase for x = 1. The substitution greatly enhanced the first hydrogenation and makes it possible at room temperature under 20 bars of hydrogen. The capacity of all substituted alloys was around 2 wt.%. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

41 pages, 13242 KiB

Open AccessArticle

Engineering Challenges of Solution and Slurry-Phase Chemical Hydrogen Storage Materials for Automotive Fuel Cell Applications

by Troy Semelsberger, Jason Graetz, Andrew Sutton and Ewa C. E. Rönnebro

Molecules 2021, 26(6), 1722; https://doi.org/10.3390/molecules26061722 - 19 Mar 2021

Cited by 5 | Viewed by 2724

Abstract

We present the research findings of the DOE-funded Hydrogen Storage Engineering Center of Excellence (HSECoE) related to liquid-phase and slurry-phase chemical hydrogen storage media and their potential as future hydrogen storage media for automotive applications. Chemical hydrogen storage media other than neat liquid [...] Read more.

We present the research findings of the DOE-funded Hydrogen Storage Engineering Center of Excellence (HSECoE) related to liquid-phase and slurry-phase chemical hydrogen storage media and their potential as future hydrogen storage media for automotive applications. Chemical hydrogen storage media other than neat liquid compositions will prove difficult to meet the DOE system level targets. Solid- and slurry-phase chemical hydrogen storage media requiring off-board regeneration are impractical and highly unlikely to be implemented for automotive applications because of the formidable task of developing solid- or slurry-phase transport systems that are commercially reliable and economical throughout the entire life cycle of the fuel. Additionally, the regeneration cost and efficiency of chemical hydrogen storage media is currently the single most prohibitive barrier to implementing chemical hydrogen storage media. Ideally, neat liquid-phase chemical hydrogen storage media with net-usable gravimetric hydrogen capacities of greater than 7.8 wt% are projected to meet the 2017 DOE system level gravimetric and volumetric targets. The research presented herein is a collection of research findings that do not in and of themselves warrant a dedicated manuscript. However, the collection of results do, in fact, highlight the engineering challenges and short-comings in scaling up and demonstrating fluid-phase ammonia borane and alane compositions that all future materials researchers working in hydrogen storage should be aware of. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Figure 1

10 pages, 1413 KiB

Open AccessArticle

Kinetics of the Lattice Response to Hydrogen Absorption in Thin Pd and CoPd Films

by Sudhansu Sekhar Das, Gregory Kopnov and Alexander Gerber

Molecules 2020, 25(16), 3597; https://doi.org/10.3390/molecules25163597 - 7 Aug 2020

Cited by 11 | Viewed by 2810

Abstract

Hydrogen can penetrate reversibly a number of metals, occupy the interstitial sites and cause large expansion of the crystal lattice. The question discussed here is whether the kinetics of the structural response matches hydrogen absorption. We show that thin Pd and CoPd films [...] Read more.

Hydrogen can penetrate reversibly a number of metals, occupy the interstitial sites and cause large expansion of the crystal lattice. The question discussed here is whether the kinetics of the structural response matches hydrogen absorption. We show that thin Pd and CoPd films exposed to a relatively rich hydrogen atmosphere (4% H₂) inflate irreversibly, demonstrate the controllable shape memory, and duration of the process can be of orders of magnitude longer than hydrogen absorption. The dynamics of the out-of-equilibrium plastic creep are well described by the Avrami-type model of the nucleation and lateral domain wall expansion of the swelled sites. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Figure 1

15 pages, 7233 KiB

Open AccessFeature PaperArticle

Upcycling of Spent NiMH Battery Material—Reconditioned Battery Alloys Show Faster Activation and Reaction Kinetics than Pristine Alloys

by Yang Shen, Erik Svensson Grape, Dag Noréus, Erika Widenkvist and Stina Starborg

Molecules 2020, 25(10), 2338; https://doi.org/10.3390/molecules25102338 - 17 May 2020

Cited by 3 | Viewed by 10877

Abstract

During formation and cycling of nickel–metal hydride (NiMH cells), surface corrosion on the metal hydride particles forms a porous outer layer of needle-shaped rare-earth hydroxide crystals. Under this layer, a denser but thinner oxidized layer protects the inner metallic part of the MH [...] Read more.

During formation and cycling of nickel–metal hydride (NiMH cells), surface corrosion on the metal hydride particles forms a porous outer layer of needle-shaped rare-earth hydroxide crystals. Under this layer, a denser but thinner oxidized layer protects the inner metallic part of the MH electrode powder particles. Nano-sized nickel-containing clusters that are assumed to promote the charge and discharge reaction kinetics are also formed here. In this study, mechanical treatments are tested to recycle hydrogen storage alloys from spent NiMH batteries. This removes the outer corroded surface of the alloy particles, while maintaining the catalytic properties of the surface. Scanning electron microscopy images and powder X-ray diffraction measurements show that the corrosion layer can be partly removed by ball milling or sonication, combined with a simple washing procedure. The reconditioned alloy powders exhibit improved high rate properties and activate more quickly than the pristine alloy. This indicates that the protective interphase layer created on the alloy particle during their earlier cycling is rather stable. The larger active surface that is created by the mechanical impact on the surface by the treatments also improves the kinetic properties. Similarly, the mechanical strain during cycling cracks the alloy particles into finer fragments. However, some of these particles form agglomerates, reducing the accessibility for the electrolyte and rendering them inactive. The mechanical treatment also separates the agglomerates and thus further promotes reaction kinetics in the upcycled material. Altogether, this suggests that the MH electrode material can perform better in its second life in a new battery. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Figure 1

21 pages, 975 KiB

Open AccessArticle

Destabilization of NaBH₄ by Transition Metal Fluorides

by Isabel Llamas Jansa, Georgios N. Kalantzopoulos, Kari Nordholm and Bjørn C. Hauback

Molecules 2020, 25(4), 780; https://doi.org/10.3390/molecules25040780 - 12 Feb 2020

Cited by 14 | Viewed by 2859

Abstract

With the goal of improving performance of a hydrogen-rich storage medium, the influence of a collection of first and second period transition metal fluorides on the destabilization of NaBH₄ is studied on samples produced by ball milling NaBH₄ with 2 mol% [...] Read more.

With the goal of improving performance of a hydrogen-rich storage medium, the influence of a collection of first and second period transition metal fluorides on the destabilization of NaBH₄ is studied on samples produced by ball milling NaBH₄ with 2 mol% of a metal fluoride additive. The effects obtained by increasing additive amount and changing oxidation state are also evaluated for NbF₅, CeF₃, and CeF₄. The as-milled products are characterized by in-house power X-ray diffraction, while the hydrogen release and decomposition are monitored by temperature programmed desorption with residual gas analysis, differential scanning calorimetry, and thermogravimetry. The screening of samples containing 2 mol% of additive shows that distinctive groups of transition metal fluorides affect the ball milling process differently depending on their enthalpy of formation, melting point, or their ability to react at the temperatures achieved during ball milling. This leads to the formation of NaBF₄ in the case of TiF₄, MnF₃, VF₄, CdF₂, NbF₅, AgF, and CeF₃ and the presence of the metal in CrF₃, CuF₂, and AgF. There is no linear correlation between the position of the transition metal in the periodic table and the observed behavior. The thermal behavior of the products after milling is given by the remaining NaBH₄, fluoride, and the formation of intermediate metastable compounds. A noticeable decrease of the decomposition temperature is seen for the majority of the products, with the exceptions of the samples containing YF₃, AgF, and CeF₃. The largest decrease of the decomposition temperature is observed for NbF₅. When comparing increasing amounts of the same additive, the largest decrease of the decomposition temperature is observed for 10 mol% of NbF₅. Higher amounts of additive result in the loss of the NaBH₄ thermal signal and ultimately the loss of the crystalline borohydride. When comparing additives with the same transition metal and different oxidation states, the most efficient additive is found to be the one with a higher oxidation state. Furthermore, among all the samples studied, higher oxidation state metal fluorides are found to be the most destabilizing agents for NaBH₄. Overall, the present study shows that there is no single parameter affecting the destabilization of NaBH₄ by transition metal fluorides. Instead, parameters such as the transition metal electronegativity and oxidation state or the enthalpy of formation of the fluoride and its melting point are competing to influence the destabilization. In particular, it is found that the combination of a high metal oxidation state and a low fluoride melting point will enhance destabilization. This is observed for MnF₃, NbF₅, NiF₂, and CuF₂, which lead to high gas releases from the decomposition of NaBH₄ at the lowest decomposition temperatures. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Graphical abstract

14 pages, 3326 KiB

Open AccessArticle

Portable Power Generation for Remote Areas Using Hydrogen Generated via Maleic Acid-Promoted Hydrolysis of Ammonia Borane

by Taylor B. Groom, Jason R. Gabl and Timothée L. Pourpoint

Molecules 2019, 24(22), 4045; https://doi.org/10.3390/molecules24224045 - 8 Nov 2019

Cited by 3 | Viewed by 2860

Abstract

A significant drawback to ammonia borane as a hydrogen storage material is the production of ammonia gas during hydrolysis. As a possible solution, maleic acid is shown to be capable of fully promoting hydrolysis of ammonia borane while also preventing ammonia release in [...] Read more.

A significant drawback to ammonia borane as a hydrogen storage material is the production of ammonia gas during hydrolysis. As a possible solution, maleic acid is shown to be capable of fully promoting hydrolysis of ammonia borane while also preventing ammonia release in excess of single digit parts per million. The reaction is shown to be relatively insensitive towards common water contaminants, with seawater, puddle water, and synthetic urine resulting in hydrogen evolution comparable to that observed when using highly pure deionized water. A common cola beverage was also investigated as a potential water source, with results deviating from those observed when using the other water sources. The ability to use low quality water sources presents the option of acquiring water at the point of use, greatly increasing the energy density of the system during transportation. For each of the water sources being used, concentrations of ammonia in the gas products of maleic acid-promoted hydrolysis were found to be less than the lower detection limits of the employed analysis methods. Based on this reaction, a portable hydrogen reactor is reported and shown to be capable of on-demand hydrogen generation sufficient to power a proton exchange membrane fuel cell at varying loads without significant changes in system pressure. The overall power production system has substantial value in scenarios where electrical power is required but there is no access to an established electrical utility, with prime examples including disaster relief and expeditionary military operations. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Figure 1

14 pages, 1900 KiB

Open AccessFeature PaperArticle

TiVZrNb Multi-Principal-Element Alloy: Synthesis Optimization, Structural, and Hydrogen Sorption Properties

by Jorge Montero, Claudia Zlotea, Gustav Ek, Jean-Claude Crivello, Lætitia Laversenne and Martin Sahlberg

Molecules 2019, 24(15), 2799; https://doi.org/10.3390/molecules24152799 - 31 Jul 2019

Cited by 69 | Viewed by 5158

Abstract

While the overwhelming number of papers on multi-principal-element alloys (MPEAs) focus on the mechanical and microstructural properties, there has been growing interest in these alloys as solid-state hydrogen stores. We report here the synthesis optimization, the physicochemical and the hydrogen sorption properties of [...] Read more.

While the overwhelming number of papers on multi-principal-element alloys (MPEAs) focus on the mechanical and microstructural properties, there has been growing interest in these alloys as solid-state hydrogen stores. We report here the synthesis optimization, the physicochemical and the hydrogen sorption properties of Ti_0.325V_0.275Zr_0.125Nb_0.275. This alloy was prepared by two methods, high temperature arc melting and ball milling under Ar, and crystallizes into a single-phase bcc structure. This MPEA shows a single transition from the initial bcc phase to a final bct dihydride and a maximum uptake of 1.7 H/M (2.5 wt%). Interestingly, the bct dihydride phase can be directly obtained by reactive ball milling under hydrogen pressure. The hydrogen desorption properties of the hydrides obtained by hydrogenation of the alloy prepared by arc melting or ball milling and by reactive ball milling have been compared. The best hydrogen sorption properties are shown by the material prepared by reactive ball milling. Despite a fading of the capacity for the first cycles, the reversible capacity of the latter material stabilizes around 2 wt%. To complement the experimental approach, a theoretical investigation combining a random distribution technique and first principle calculation was done to estimate the stability of the hydride. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Graphical abstract

Review

Jump to: Research

21 pages, 2368 KiB

Open AccessReview

Recent Advances and Prospects in Design of Hydrogen Permeation Barrier Materials for Energy Applications—A Review

by Ewa C. E. Rönnebro, Robert L. Oelrich and Robert O. Gates

Molecules 2022, 27(19), 6528; https://doi.org/10.3390/molecules27196528 - 2 Oct 2022

Cited by 17 | Viewed by 5369

Abstract

The hydrogen infrastructure involves hydrogen production, storage and delivery for utilization with clean energy applications. Hydrogen ingress into structural materials can be detrimental due to corrosion and embrittlement. To enable safe operation in applications that need protection from hydrogen isotopes, this review article [...] Read more.

The hydrogen infrastructure involves hydrogen production, storage and delivery for utilization with clean energy applications. Hydrogen ingress into structural materials can be detrimental due to corrosion and embrittlement. To enable safe operation in applications that need protection from hydrogen isotopes, this review article summarizes most recent advances in materials design and performance characterization of barrier coatings to prevent hydrogen isotopes’ absorption ingress and permeation. Barriers are crucial to prevent hydride formation and unwanted hydrogen effects to increase safety, materials’ lifetime and reduce cost for applications within nuclear and renewable energy. The coating may be applied on a material that requires protection from hydrogen pick-up, transport and hydride formation in hydrogen storage containers, in pipelines, spent nuclear fuel storage or in nuclear reactors. While existing, commercial coatings that have been much in use may be satisfactory for various applications, it is desirable to evaluate whether alternative coating concepts can provide a greater resistance to hydrogen isotope permeation along with other improved properties, such as mechanical strength and thermal resistance. The information presented here is focusing on recent findings within the past 5–7 years of promising hydrogen barriers including oxides, nitrides, carbon, carbide, MAX-phases and metals and their mechanical strength, hydrogen pick-up, radiation resistance and coating manufacturing techniques. A brief introduction to hydrogen permeation is provided. Knowledge gaps were identified to provide guidance for material’s research prospects. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization 2.0)

► Show Figures

Figure 1

11 pages, 2340 KiB

Open AccessReview

Overview of the Structure–Dynamics–Function Relationships in Borohydrides for Use as Solid-State Electrolytes in Battery Applications

by Tabbetha A. Dobbins

Molecules 2021, 26(11), 3239; https://doi.org/10.3390/molecules26113239 - 28 May 2021

Cited by 6 | Viewed by 3768

Abstract

The goal of this article is to highlight crucial breakthroughs in solid-state ionic conduction in borohydrides for battery applications. Borohydrides, M^z+B_xH_y, form in various molecular structures, for example, nido-M⁺BH₄; closo-M²⁺B₁₀ [...] Read more.

The goal of this article is to highlight crucial breakthroughs in solid-state ionic conduction in borohydrides for battery applications. Borohydrides, M^z+B_xH_y, form in various molecular structures, for example, nido-M⁺BH₄; closo-M²⁺B₁₀H₁₀; closo-M²⁺B₁₂H₁₂; and planar-M⁶⁺B₆H₆ with M = cations such as Li⁺, K⁺, Na⁺, Ca²⁺, and Mg²⁺, which can participate in ionic conduction. This overview article will fully explore the phase space of boron–hydrogen chemistry in order to discuss parameters that optimize these materials as solid electrolytes for battery applications. Key properties for effective solid-state electrolytes, including ionic conduction, electrochemical window, high energy density, and resistance to dendrite formation, are also discussed. Because of their open structures (for closo-boranes) leading to rapid ionic conduction, and their ability to undergo phase transition between low conductivity and high conductivity phases, borohydrides deserve a focused discussion and further experimental efforts. One challenge that remains is the low electrochemical stability of borohydrides. This overview article highlights current knowledge and additionally recommends a path towards further computational and experimental research efforts. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Figure 1

22 pages, 1947 KiB

Open AccessFeature PaperReview

Anion and Cation Dynamics in Polyhydroborate Salts: NMR Studies

by Alexander V. Skripov, Alexei V. Soloninin, Olga A. Babanova and Roman V. Skoryunov

Molecules 2020, 25(12), 2940; https://doi.org/10.3390/molecules25122940 - 26 Jun 2020

Cited by 24 | Viewed by 4818

Abstract

Polyhydroborate salts represent the important class of energy materials attracting significant recent attention. Some of these salts exhibit promising hydrogen storage properties and/or high ionic conductivities favorable for applications as solid electrolytes in batteries. Two basic types of thermally activated atomic jump motion [...] Read more.

Polyhydroborate salts represent the important class of energy materials attracting significant recent attention. Some of these salts exhibit promising hydrogen storage properties and/or high ionic conductivities favorable for applications as solid electrolytes in batteries. Two basic types of thermally activated atomic jump motion are known to exist in these materials: the reorientational (rotational) motion of complex anions and the translational diffusion of cations or complex anions. The present paper reviews recent progress in nuclear magnetic resonance (NMR) studies of both reorientational and diffusive jump motion in polyhydroborate salts. The emphasis is put on sodium and lithium closo-borates exhibiting high ionic conductivity and on borohydride-based systems showing extremely fast reorientational motion down to low temperatures. For these systems, we discuss the effects of order–disorder phase transitions on the parameters of reorientations and diffusive jumps, as well as the mechanism of low-temperature rotational tunneling. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Graphical abstract

25 pages, 4605 KiB

Open AccessReview

Beyond Typical Electrolytes for Energy Dense Batteries

by Rana Mohtadi

Molecules 2020, 25(8), 1791; https://doi.org/10.3390/molecules25081791 - 14 Apr 2020

Cited by 23 | Viewed by 4856

Abstract

The ever-rising demands for energy dense electrochemical storage systems have been driving interests in beyond Li-ion batteries such as those based on lithium and magnesium metals. These high energy density batteries suffer from several challenges, several of which stem from the flammability/volatility of [...] Read more.

The ever-rising demands for energy dense electrochemical storage systems have been driving interests in beyond Li-ion batteries such as those based on lithium and magnesium metals. These high energy density batteries suffer from several challenges, several of which stem from the flammability/volatility of the electrolytes and/or instability of the electrolytes with either the negative, positive electrode or both. Recently, hydride-based electrolytes have been paving the way towards overcoming these issues. Namely, highly performing solid-state electrolytes have been reported and several key challenges in multivalent batteries were overcome. In this review, the classes of hydride-based electrolytes reported for energy dense batteries are discussed. Future perspectives are presented to guide research directions in this field. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Figure 1

39 pages, 6200 KiB

Open AccessReview

Tuning LiBH₄ for Hydrogen Storage: Destabilization, Additive, and Nanoconfinement Approaches

by Julián Puszkiel, Aurelien Gasnier, Guillermina Amica and Fabiana Gennari

Molecules 2020, 25(1), 163; https://doi.org/10.3390/molecules25010163 - 31 Dec 2019

Cited by 52 | Viewed by 5514

Abstract

Hydrogen technology has become essential to fulfill our mobile and stationary energy needs in a global low–carbon energy system. The non-renewability of fossil fuels and the increasing environmental problems caused by our fossil fuel–running economy have led to our efforts towards the application [...] Read more.

Hydrogen technology has become essential to fulfill our mobile and stationary energy needs in a global low–carbon energy system. The non-renewability of fossil fuels and the increasing environmental problems caused by our fossil fuel–running economy have led to our efforts towards the application of hydrogen as an energy vector. However, the development of volumetric and gravimetric efficient hydrogen storage media is still to be addressed. LiBH₄ is one of the most interesting media to store hydrogen as a compound due to its large gravimetric (18.5 wt.%) and volumetric (121 kgH₂/m³) hydrogen densities. In this review, we focus on some of the main explored approaches to tune the thermodynamics and kinetics of LiBH₄: (I) LiBH₄ + MgH₂ destabilized system, (II) metal and metal hydride added LiBH₄, (III) destabilization of LiBH₄ by rare-earth metal hydrides, and (IV) the nanoconfinement of LiBH₄ and destabilized LiBH₄ hydride systems. Thorough discussions about the reaction pathways, destabilizing and catalytic effects of metals and metal hydrides, novel synthesis processes of rare earth destabilizing agents, and all the essential aspects of nanoconfinement are led. Full article

(This article belongs to the Special Issue Advances in Hydrogen Storage Materials for Energy Utilization)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Advances in Hydrogen Storage Materials for Energy Utilization 2.0

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Related Special Issue

Published Papers (21 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI