scholarly journals Metastable Metal Hydrides for Hydrogen Storage

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Jason Graetz
Keyword(s):  
New Media ◽  
Hydrogen Storage ◽  
High Capacity ◽  
Metal Hydrides ◽  
Decomposition Reaction ◽  
Hydrogen Gas ◽  
Production Costs ◽  
Ambient Conditions ◽  
New Methods ◽  
Decomposition Enthalpy

The possibility of using hydrogen as a reliable energy carrier for both stationary and mobile applications has gained renewed interest in recent years due to improvements in high temperature fuel cells and a reduction in hydrogen production costs. However, a number of challenges remain and new media are needed that are capable of safely storing hydrogen with high gravimetric and volumetric densities. Metal hydrides and complex metal hydrides offer some hope of overcoming these challenges; however, many of the high capacity “reversible” hydrides exhibit a large endothermic decomposition enthalpy making it difficult to release the hydrogen at low temperatures. On the other hand, the metastable hydrides are characterized by a low reaction enthalpy and a decomposition reaction that is thermodynamically favorable under ambient conditions. The rapid, low temperature hydrogen evolution rates that can be achieved with these materials offer much promise for mobile PEM fuel cell applications. However, a critical challenge exists to develop new methods to regenerate these hydrides directly from the reactants and hydrogen gas. This spotlight paper presents an overview of some of the metastable metal hydrides for hydrogen storage and a few new approaches being investigated to address the key challenges associated with these materials.

First-Principles Study on the Hydrogen Storage of Sandwich-Type Dimetallocenes

2013 ◽  
Vol 677 ◽  
pp. 149-152
Author(s):  
Bo An ◽  
Hai Yan Zhu
Keyword(s):  
Hydrogen Storage ◽  
First Principles ◽  
Storage Capacity ◽  
High Capacity ◽  
First Principles Calculation ◽  
Hydrogen Storage Materials ◽  
Ambient Conditions ◽  
Hydrogen Storage Capacity ◽  
Hydrogen Molecules ◽  
Sandwich Type

The paper mainly focuses on the ability of absorbing hydrogen molecule of the dimetallocene (C5H5)2TM2(TM=Ti/Zn/Cu/Ni) based on the first-principles calculation. The result indicates that these compounds can adsorb up to eight hydrogen molecules, the binding energy is 0.596eV/H2 for Cp2Ti2, 0.802eV/H2 for Cp2Zn2, 0.422eV/H2 for Cp2Cu2 and 0.182eV/H2 for Cp2Ni2 respectively. The corresponding gravimetric hydrogen-storage capacity is 7.1wt% for Cp2Ti2, 6.2wt% for Cp2Zn2, 6.3wt% for Cp2Cu2 and 6.5wt% for Cp2Ni2 respectively. These sandwich-type organometallocenes proposed in this work are favorable for reversible adsorption and desorption of hydrogen under ambient conditions. These predictions will likely provide a new route for developing novel high-capacity hydrogen-storage materials.

scholarly journals From gangue to the fuel-cells application

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
M. Sherif El-Eskandarany ◽  
Sultan Majed Al-Salem ◽  
Naser Ali ◽  
Mohammad Banyan ◽  
Fahad Al-Ajmi ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
High Capacity ◽  
Life Time ◽  
Clean Energy ◽  
Hydrogen Gas ◽  
Desorption Kinetics ◽  
Long Cycle Life ◽  
Electrical Systems ◽  
Cu Alloy ◽  
Traditional Approaches

AbstractHydrogen, which is a new clean energy option for future energy systems possesses pioneering characteristics making it a desirable carbon-free energy carrier. Hydrogen storage plays a crucial role in initiating a hydrogen economy. Due to its low density, the storage of hydrogen in the gaseous and liquids states had several technical and economic challenges. Despite these traditional approaches, magnesium hydride (MgH2), which has high gravimetric and volumetric hydrogen density, offers an excellent potential option for utilizing hydrogen in automobiles and other electrical systems. In contrast to its attractive properties, MgH2 should be mechanically and chemically treated to reduce its high activation energy and enhance its modest hydrogen sorption/desorption kinetics. The present study aims to investigate the influence of doping mechanically-treated Mg metal with 5 wt% amorphous Zr2Cu abrasive nanopowders in improving its kinetics and cyclability behaviors. For the first time, solid-waste Mg, Zr, and Cu metals were utilized for preparing MgH2 and amorphous Zr2Cu alloy (catalytic agent), using hydrogen gas-reactive ball milling, and arc melting techniques, respectively. This new nanocomposite system revealed high-capacity hydrogen storage (6.6 wt%) with superior kinetics and extraordinary long cycle-life-time (1100 h) at 250 °C.

scholarly journals A Comparison of Hydrogen Storage in Pt, Pd and Pt/Pd Alloys Loaded Disordered Mesoporous Hollow Carbon Spheres

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 639 ◽  
Author(s):  
Martyna Baca ◽  
Krzysztof Cendrowski ◽  
Wojciech Kukulka ◽  
Grzegorz Bazarko ◽  
Dariusz Moszyński ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Spillover Effect ◽  
Metal Hydrides ◽  
Hydrogen Uptake ◽  
Carbon Spheres ◽  
Ambient Conditions ◽  
Two Factors ◽  
Size Of Particles ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

Comprehensive study to evaluate the ability of hydrogen uptake by disordered mesoporous hollow carbon spheres doped witch metal such as Pt, Pd or Pt/Pd was conducted. They were synthesized facilely using sonication and then calcination process under vacuum at the temperature of 550 °C. The effect on hydrogen sorption at neat-ambient conditions (40 °C, up to 45 bar) was thoroughly analyzed. The results clearly revealed that metal functionalization has a significant impact on the hydrogen storage capacity as the mechanism of gas uptake depends on two factors: metal type and certain size of particles. Thus, functionalized spheres adsorb hydrogen by physisorption forming metal hydrides or metal hydrides combined with hydrogen spillover effect. As a result, a sample with narrower distribution of nanoparticles and smaller specific size exhibited enhanced hydrogen uptake.

Computational Study of Hydrogen Storage Performance in Metal Hydride Reactors

2010 ◽  
Author(s):  
Chih-Ang Chung ◽  
Ci-Siang Lin ◽  
Ci-Jyun Ho
Keyword(s):  
Heat Transfer ◽  
Hydrogen Storage ◽  
Gas Flow ◽  
Computational Study ◽  
Metal Hydrides ◽  
Reaction Rates ◽  
High Energy ◽  
Hydrogen Gas ◽  
High Energy Density ◽  
Equilibrium Pressure

Hydrogen as the most abundant element on Earth is viewed to be a promising energy carrier. For transmission, hydrogen stored as metal hydrides is a potent candidate for its advantages in safe and reliability and being able to offer high energy density compared to the conventional ways such as high pressure gas and liquefaction. Metal hydriding is basically an exothermic process. The heat released will cause an increase in temperature and raise the absorption equilibrium pressure as high as that of the supplied hydrogen gas, which may in turn stop the hydriding process. On the other hand, metal dehydriding is an endothermic process. A temperature decrease can retard desorption and even bring down the dissociation equilibrium pressure as low as the back pressure to stop dehydriding. Therefore, reducing thermal resistance of the storage vessels and enhancing heat transfer of the storage system have become a critical issue for the success of hydrogen storage using metal hydrides. This work models the metal hydriding/dehydriding process in order to assess the vessel design on heat transfer enhancement to improve the performance of hydrogen storage with metal hydrides. First of all, the thermal-fluid behavior of hydrogen storage was modeled including gas flow and energy equations. The vessel is considered to be equipped with an air pipe at the centre line with internal fins. Detailed theoretical models that describe force convection of the heat exchange pipe and natural convection at the lateral wall are constructed. Results from the simulation show that the addition of a concentric heat exchanger pipe with fins can enhance the reaction rates. The work demonstrates how computer aided engineering can be applied to evaluate the performance of hydrogen storage designs, and help reduce experimental efforts in developing the hydrogen storage systems.

scholarly journals The Influence of Fe on the Structure and Hydrogen Sorption Properties of Ti-V-Based Metal Hydrides

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2874
Author(s):  
Magnus M. Nygård ◽  
Magnus H. Sørby ◽  
Arne A. Grimenes ◽  
Bjørn C. Hauback
Keyword(s):  
Hydrogen Storage ◽  
Metal Hydrides ◽  
Hydrogen Gas ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Fe Content ◽  
Overall Performance ◽  
Face Centered ◽  
Desorption Enthalpy

Ti-V-based metal hydrides have decent overall performance as hydrogen storage materials, but V is expensive and it is therefore tempting to replace it by less expensive ferrovanadium containing about 20% Fe. In the present work we have investigated how Fe influences the structure and hydrogen storage properties of (Ti0.7V0.3)1−zFez alloys with e r r o r t y p e c e z ∈ { 0 , 0.03, 0.06, 0.1, 0.2, 0.3} using synchrotron radiation powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry and manometric measurements performed in a Sieverts apparatus. The alloys form body-centered cubic (bcc) crystal structures for all considered values of z, and the addition of Fe causes the unit cell to contract. When exposed to hydrogen gas, the bcc alloys form face-centered cubic (fcc) hydrides if e r r o r t y p e c e z ≤ 0 . 1 while other hydrogen-containing phases are formed for higher Fe-contents. The hydrogen capacities of the fcc hydrides at 20 bar are not significantly influenced by the addition of Fe and reach 3.2(3) wt% in (Ti0.7V0.3)0.9Fe0.1H1.6(2). For higher Fe contents the hydrogen capacity is decreased. The absorption kinetics are fast and the reactions are complete within minutes when the alloys are exposed to 20 bar H2 at room temperature. Increasing Fe content reduces the desorption enthalpy, onset temperature and activation energy.

Systems Modeling of Chemical Hydride Hydrogen Storage Materials for Fuel Cell Applications

2011 ◽  
Vol 8 (6) ◽  
Author(s):  
Kriston Brooks ◽  
Maruthi Devarakonda ◽  
Scot Rassat ◽  
Jamie Holladay
Keyword(s):  
Fuel Cell ◽  
Hydrogen Storage ◽  
Storage System ◽  
Fixed Bed ◽  
Hydrogen Gas ◽  
Fixed Bed Reactor ◽  
Ambient Conditions ◽  
High Hydrogen ◽  
Pressure Drops ◽  
Reactor Models

A fixed bed reactor was designed, modeled and simulated for hydrogen storage on-board the vehicle for PEM fuel cell applications. Ammonia borane was selected by DOE’s Hydrogen Storage Engineering Center of Excellence as the initial chemical hydride of study because of its high hydrogen storage capacity (up to ∼16% by weight for the release of ∼2.5 molar equivalents of hydrogen gas) and its stability under typical ambient conditions. The design evaluated consisted of a tank with eight thermally isolated sections in which H2 flows freely between sections to provide ballast. Heating elements are used to initiate reactions in each section when pressure drops below a specified level in the tank. Reactor models in Excel and COMSOL were developed to demonstrate the proof-of-concept, which was then used to develop systems models in Matlab/Simulink. Experiments and drive cycle simulations showed that the storage system meets thirteen 2010 DOE targets in entirety and the remaining four at greater than 60% of the target.

Metal Hydrides for Hydrogen Storage

2007 ◽  
Vol 1041 ◽  
Author(s):  
Jason Graetz ◽  
James J Reilly ◽  
James Wegrzyn
Keyword(s):  
Fuel Cell ◽  
Chemical Composition ◽  
New Media ◽  
Hydrogen Storage ◽  
Metal Hydrides ◽  
Hydrogen Economy ◽  
Automotive Fuel ◽  
Metal Atoms ◽  
Hydride Hydrogen ◽  
New Form

AbstractThe emergence of a Hydrogen Economy will require the development of new media capable of safely storing hydrogen with high gravimetric and volumetric densities. Metal hydrides and complex metal hydrides, where hydrogen is chemically bonded to the metal atoms in the bulk, offer some hope of overcoming the challenges associated with hydrogen storage. Many of the more promising hydrogen materials are tailored to meet the unique demands of a low temperature automotive fuel cell and are therefore either entirely new (e.g. in structural or chemical composition) or in some new form (e.g. morphology, crystallite size, catalysts). This proceeding presents an overview of some of the challenges associated with metal hydride hydrogen storage and a few new approaches being investigated to address these challenges.

A rigorous electrochemical ammonia electrolysis protocol with in-operando quantitative analysis

2021 ◽  
Author(s):  
Yejin Yang ◽  
Jeongwon Kim ◽  
Hyoi Jo ◽  
Arim Seong ◽  
Minzae Lee ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Hydrogen Production ◽  
Hydrogen Storage ◽  
Liquid Fuel ◽  
High Capacity ◽  
In Operando

Ammonia has emerged as attractive liquid fuel for hydrogen production owing to its facile transportation, high capacity of hydrogen storage, and ecofriendly environmental products (N2 and H2). Moreover, the electrolysis...

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