Nanocrystalline Mg-based hydrides for hydrogen storage

2001 ◽  
Vol 676 ◽  
Author(s):  
W. Oelerich ◽  
T. Klassen ◽  
R. Bormann
Keyword(s):  
Hydrogen Storage ◽  
Mobile Applications ◽  
Research Effort ◽  
Metal Hydrides ◽  
Clean Energy ◽  
High Energy ◽  
Sorption Kinetics ◽  
Desorption Kinetics ◽  
Gaseous State ◽  
Sorption Behaviour

ABSTRACTHydrogen is the ideal means of energy storage for transportation and conversion of energy in a comprehensive clean-energy concept. However, appropriate storage facilities, both for stationary and for mobile applications, are complicated, because of the very low boiling point of hydrogen (20.4 K at 1 atm) and its low density in the gaseous state (90 g/m3). Furthermore, the storage of hydrogen in liquid or gaseous form imposes safety problems, in particular for mobile applications, e.g. the future zero-emission vehicle. Metal hydrides are a safe alternative for H-storage and, in addition, have a high volumetric energy density that is about 60% higher than that of liquid hydrogen. Mg hydride has a high storage capacity by weight and is therefore favoured for automotive applications. However, so far light metal hydrides have not been considered competitive because of their rather sluggish sorption kinetics. Filling a tank could take several hours. Moreover, the hydrogen desorption temperature of about 300 °C is rather high for most applications. A breakthrough in hydrogen storage technology was achieved by preparing nanocrystalline hydrides using high-energy ball milling. These new materials show very fast aband desorption kinetics within few minutes, thus qualifying lightweight Mg-based hydrides for storage application. In this paper recent detailed results on the sorption behaviour of nanocrystalline Mg and Mg-based alloys are presented. In a following research effort the sorption kinetics of nanocrystalline Mg has been further enhanced by catalyst additions. Furthermore, different transition metals have been added to Mg to achieve a thermodynamic destabilisation of the hydride, thus lowering the desorption temperatures to about 230 °C. The newly developed materials are currently being tested in prototype storage tanks.

Enhancement of Hydrogen Storage in Metals by Using a New Technique in Severe Plastic Deformations

2019 ◽  
Vol 799 ◽  
pp. 173-178 ◽  
Author(s):  
Babak Shahreza Omranpour ◽  
Lembit Kommel ◽  
E. Garcia Sanchez ◽  
Yulia Ivanisenko ◽  
Jacques Huot
Keyword(s):  
Hydrogen Storage ◽  
High Pressure Torsion ◽  
Metal Hydrides ◽  
Clean Energy ◽  
Green Energy ◽  
Energy Investment ◽  
Energy Applications ◽  
Viable Solution ◽  
Diffraction Patterns ◽  
A New Technique

Hydrogen is expected to be a viable solution for green-energy investment in future. However, hydrogen storage is a big challenge for stationary and mobile applications. Severe Plastic Deformation (SPD) techniques are well-known to be effective in enhancement of hydrogenation in metals hydrides. This paper shows the effect of a novel SPD technique named “High Pressure Torsion Extrusion-HPTE” on the hydrogenation of metal hydrides and compare it with the conventional method of ECAP. Results of mechanical testing and X-ray diffraction patterns showed significant enhancement in hardness and microstructural refinement in materials after HPTE. Accordingly, hydrogenation kinetics improved dramatically. This achievement could be an initiative to implement HPTE in synthesis of metal hydrides for clean energy applications.

Synthesis of Mg (NH2)2 and Hydrogen Storage Properties of Mg (NH2)2–LiH System

2011 ◽  
Vol 347-353 ◽  
pp. 3609-3615
Author(s):  
Ke Zhang ◽  
Xiao Yu Zhao ◽  
Shu Li Liu ◽  
Zhong Qiu Cao ◽  
Hui Zhang
Keyword(s):  
Hydrogen Storage ◽  
Heat Treating ◽  
High Energy ◽  
Molar Ratio ◽  
Desorption Kinetics ◽  
Arrhenius Activation Energy ◽  
Hydrogen Storage Properties ◽  
Desorption Reaction ◽  
Storage Properties ◽  
Static Hydrogen

Mg(NH2)2 was synthesized by first high energy milling MgH2 powder in a 99.995% NH3 atmosphere and then heat treating at 300oC, and hydrogen storage properties of prepared Mg(NH2)2+2.2LiH (molar ratio) had been studied in the temperature range of 150-240oC. It was found that mechanical milling of Mg (NH2)2 and LiH with molar ratio 1:2.2 followed by heat treatment under static hydrogen pressure and dehydrogenating at 208.5oC yields the desired reversible hydrogen storage phase: Li2Mg(NH)2. Desorption kinetics reveal a rapid reaction for the system and the maximum hydrogen capacity can reach 4.6 wt. % at 208.5oC. The system starts to dehydrogenate at 150oC and the Arrhenius activation energy Ea of desorption reaction can be determined to be 25.8 kJ/mol H2 based on the data of kinetics. Additionally, the desorption reaction enthalpy (H) and entropy (S) are calculated to be 42.8 kJ/mol H2 and 149.2 J. K-1/ mol H2 respectively from PCI measurements.

scholarly journals Engineering oxygen vacancies in Na2Ti3O7 for boosting its catalytic performance in MgH2 hydrogen storage

2021 ◽  
Author(s):  
Huanhuan Zhang ◽  
Qianqian Kong ◽  
Song Hu ◽  
Dafeng Zhang ◽  
Haipeng Chen ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Rational Design ◽  
Oxygen Vacancies ◽  
High Efficiency ◽  
Retention Rate ◽  
Storage System ◽  
Critical Role ◽  
Catalytic Performance ◽  
Sorption Kinetics ◽  
Desorption Kinetics

Abstract Rational design of high-efficiency catalysts plays a critical role in improving the hydrogen storage performances of the MgH2. Herein, flower-like Na2Ti3O7 catalyst with rich oxygen vacancies (Na2Ti3O7-Ov) was synthesized from Ti3C2-MXene and demonstrated to remarkably enhance the hydrogen storage of MgH2. Specifically, with an addition of 5 wt.% Na2Ti3O7-Ov, the initial dehydrogenation temperature of the MgH2 + 5Na2Ti3O7-Ov composite reduced substantially from 287 °C (for MgH2) to 183 °C. Moreover, the MgH2 + 5Na2Ti3O7-Ov composite exhibited fast hydrogen ab/desorption kinetics and superb reversible hydrogen storage performance with a retention rate of 90.1 % after 10 cycles attributed to the higher structural stability of Na2Ti3O7-Ov. Both experimental and theoretical results confirm that the oxygen vacancies in Na2Ti3O7-Ov reduce the reaction activation energy during MgH2 dehydrogenation, hence accounting for the excellent hydrogen sorption kinetics. This work would lead to new design and development of advanced defect-based nano-catalysts for the MgH2 hydrogen storage system.

Effect of the Excess Volume of Lattice Defects on the Enthalpy of Formation and Desorption Temperature of Metal Hydrides

2007 ◽  
Author(s):  
Vincent Be´rube´ ◽  
Gregg Radtke ◽  
Gang Chen ◽  
Mildred Dresselhaus
Keyword(s):  
Enthalpy Of Formation ◽  
Excess Volume ◽  
Lattice Structure ◽  
Boundary Energy ◽  
Metal Hydrides ◽  
High Energy ◽  
Sorption Kinetics ◽  
Structural Defects ◽  
Desorption Process ◽  
The Enthalpy Of Formation

Metal and complex hydrides offer very promising prospects for hydrogen storage that reach the DOE targets for 2015. However, slow sorption kinetics and high release temperature must be addressed to make automotive applications feasible. Reducing the enthalpy of formation by destabilizing the hydride reduces the heat released during the hydrogenation phase and conversely allows desorption at a lower temperature. High-energy ball milling has been shown to decrease the release temperature, increase reaction kinetics and lower the enthalpy of formation in certain cases. Increased surface and grain boundary energy could play a role in reducing the enthalpy of formation, but the predicted magnitude is too small to account for experimental observations. As the particle and grain sizes are reduced considerably under high-energy treatments, structural defects and deformations are introduced. These regions can be characterized by an excess volume due to deformations in the lattice structure, and have a significant effect on the material properties of the hydride. We propose a thermodynamic model that characterizes the excess energy present in the deformed regions to explain the change in physical properties of metal hydrides. An experimental investigation using the TEM to study the effect of lattice deformations and other nanostructures on the desorption process is underway.

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.

Progress in Magnesium-Based Hydrogen Storage Materials

2012 ◽  
Vol 174-177 ◽  
pp. 1339-1343 ◽  
Author(s):  
Hong Min Kan ◽  
Ning Zhang ◽  
Xiao Yang Wang ◽  
Hong Sun
Keyword(s):  
Hydrogen Storage ◽  
Alternative Energy ◽  
Fossil Fuels ◽  
Clean Energy ◽  
High Energy ◽  
High Energy Density ◽  
Potential Candidate ◽  
Promising Alternative ◽  
Oxygen Contamination ◽  
Kinetics Of

Hydrogen is considered a promising alternative energy carrier that can potentially facilitate the transition from fossil fuels to sources of clean energy because of its prominent advantages such as high energy density, great variety of potential sources, light weight and low environmental impact (water is the sole combustion product). Due to low price and abundance magnesium should be considered as a potential candidate for hydrogen storage. Recent progress in the application of Magnesium-based nanostructured and composite materials in hydrogen storage is presented in this review. The main focus is on the synthesis of composite material, the design of nanocomposite material, the improvement of the thermodynamical properties and kinetics of hydrogenation/dehydrogenation and the improvement of resistance towards oxygen contamination.

Improved Hydrogen Desorption Kinetics of MgH2 Nanoparticles by Using TiC Nanocatalyst

2012 ◽  
Vol 510-511 ◽  
pp. 371-377 ◽  
Author(s):  
N.A. Niaz ◽  
S.T. Hussain ◽  
S. Nasir ◽  
I. Ahmad
Keyword(s):  
Hydrogen Storage ◽  
Surface Condition ◽  
Hydrogen Desorption ◽  
High Energy ◽  
Desorption Kinetics ◽  
X Rays ◽  
Scanning Calorimetry ◽  
Practical Applications ◽  
Slow Kinetics ◽  
Kinetics Of

Magnesium hydride (MgH2) is considered to be a promising hydrogen storage material because of its high gravimetric and volumetric storage capacities. However, its slow kinetics and high desorption temperature (> 300 °C) limit the practical applications. We have selected TiC nanoparticles to modify the hydrogen storage properties of MgH2. First, Mg nanoparticles were synthesized by thermal desorption of bipyridyl complex of Mg and then MgH2nanoparticles were obtained by hydriding the Mg nanoparticles. Composite mixtures (MgH2+ TiC) were prepared using high-energy ball milling. Structural analysis, morphology and particle size were investigated by X-rays diffractometer (XRD) and scanning electron microscopy (SEM) respectively. Hydrogen desorption properties of MgH2was investigated with various amount of TiC nanocatalyst using differential scanning calorimetry (DSC) and seivertz type apparatus (PCT). Desorption kinetics were also studied by pressure composition isotherm (PCI). Results show that the product reveals good reversible hydrogen absorption-desorption cycles even at >150 °C. The hydrogen desorption kinetics of catalyzed and noncatalyzed MgH2could be understood by a modified first-order reaction model, in which the surface condition was taken into account.

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.

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