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First-Principles Modeling of Hydrogen Storage in Metal Hydride Systems

Description: The objective of this project is to complement experimental efforts of MHoCE partners by using state-of-the-art theory and modeling to study the structure, thermodynamics, and kinetics of hydrogen storage materials. Specific goals include prediction of the heats of formation and other thermodynamic properties of alloys from first principles methods, identification of new alloys that can be tested experimentally, calculation of surface and energetic properties of nanoparticles, and calculation of kinetics involved with hydrogenation and dehydrogenation processes. Discovery of new metal hydrides with enhanced properties compared with existing materials is a critical need for the Metal Hydride Center of Excellence. New materials discovery can be aided by the use of first principles (ab initio) computational modeling in two ways: (1) The properties, including mechanisms, of existing materials can be better elucidated through a combined modeling/experimental approach. (2) The thermodynamic properties of novel materials that have not been made can, in many cases, be quickly screened with ab initio methods. We have used state-of-the-art computational techniques to explore millions of possible reaction conditions consisting of different element spaces, compositions, and temperatures. We have identified potentially promising single- and multi-step reactions that can be explored experimentally.
Date: May 20, 2011
Creator: Johnson, J. Karl
Partner: UNT Libraries Government Documents Department

U.S. Department of Energy Hydrogen Storage Cost Analysis

Description: The overall objective of this project is to conduct cost analyses and estimate costs for on- and off-board hydrogen storage technologies under development by the U.S. Department of Energy (DOE) on a consistent, independent basis. This can help guide DOE and stakeholders toward the most-promising research, development and commercialization pathways for hydrogen-fueled vehicles. A specific focus of the project is to estimate hydrogen storage system cost in high-volume production scenarios relative to the DOE target that was in place when this cost analysis was initiated. This report and its results reflect work conducted by TIAX between 2004 and 2012, including recent refinements and updates. The report provides a system-level evaluation of costs and performance for four broad categories of on-board hydrogen storage: (1) reversible on-board metal hydrides (e.g., magnesium hydride, sodium alanate); (2) regenerable off-board chemical hydrogen storage materials(e.g., hydrolysis of sodium borohydride, ammonia borane); (3) high surface area sorbents (e.g., carbon-based materials); and 4) advanced physical storage (e.g., 700-bar compressed, cryo-compressed and liquid hydrogen). Additionally, the off-board efficiency and processing costs of several hydrogen storage systems were evaluated and reported, including: (1) liquid carrier, (2) sodium borohydride, (3) ammonia borane, and (4) magnesium hydride. TIAX applied a “bottom-up” costing methodology customized to analyze and quantify the processes used in the manufacture of hydrogen storage systems. This methodology, used in conjunction with DFMA® software and other tools, developed costs for all major tank components, balance-of-tank, tank assembly, and system assembly. Based on this methodology, the figure below shows the projected on-board high-volume factory costs of the various analyzed hydrogen storage systems, as designed. Reductions in the key cost drivers may bring hydrogen storage system costs closer to this DOE target. In general, tank costs are the largest component of system cost, responsible for at least 30 percent of total system ...
Date: March 11, 2013
Creator: Law, Karen; Rosenfeld, Jeffrey; Han, Vickie; Chan, Michael; Chiang, Helena & Leonard, Jon
Partner: UNT Libraries Government Documents Department

In-Situ Neutron Diffraction Studies of Complex Hydrogen Storage Materials

Description: The thrust of this project was to investigate the structures of important materials with potential application to hydrogen storage, in an effort to meet the DOE goals for 2010 and 2015, namely 9% (wt) and 15% (wt) respectively. Unfortunately, no material has been found, despite the efforts of many laboratories, including our own, that achieves these goals in a reversible complex hydride such as ammonia borane (NH{sub 4}BH{sub 4}), and other ammonia based compounds, or with light hydrides such as LiBH{sub 4}, due either to their irreversibility or to the high decomposition temperatures and residual simple hydrides such as LiH from the decomposition of the last named compound. Nevertheless, several important technical goals have been accomplished that could be valuable to other DOE programs and would be available for collaborative research. These include the development of a high quality glove box with controlled (low) oxygen and water content, which we continue to employ for the synthesis of potential new materials (unfunded research) and the development of a high quality neutron diffraction furnace with controlled gas environment for studies of hydrogen uptake and loss as well as for studies with other gasses. This furnace was initially constructed with an alumina (Al{sub 2}O{sub 3}) center tube to contain the sample and the flowing gas. The heaters are located in the vacuum space outside the tube and it was found that, for the low temperatures required for the study of hydrogen storage materials, the heat transfer was too poor to allow good control. At temperatures in excess of about 400C (and up to more than 1200C) the heat transfer and control are excellent. For the lower temperatures, however, the center tube was replaced by stainless steel and temperature control to 1C became possible. The paired heaters, above and below the neutron beam window ...
Date: May 13, 2013
Creator: Yelon, William B.
Partner: UNT Libraries Government Documents Department

Complex Hydrides for Hydrogen Storage

Description: This report describes research into the use of complex hydrides for hydrogen storage. The synthesis of a number of alanates, (AIH4) compounds, was investigated. Both wet chemical and mechano-chemical methods were studied.
Date: March 10, 2003
Creator: Slattery, Darlene & Hampton, Michael
Partner: UNT Libraries Government Documents Department

A Cassette Based System for Hydrogen Storage and Delivery

Description: A hydrogen storage system is described and evaluated. This is based upon a cassette, that is a container for managing hydrogen storage materials. The container is designed to be safe, modular, adaptable to different chemistries, inexpensive, and transportable. A second module receives the cassette and provides the necessary infrastructure to deliver hydrogen from the cassette according to enduser requirements. The modular concept has a number of advantages over approaches that are all in one stand alone systems. The advantages of a cassette based system are discussed, along with results from model and laboratory testing.
Date: November 29, 2006
Creator: E., Britton Wayne
Partner: UNT Libraries Government Documents Department

Hydrogen Storage in Nano-Phase Diamond at High Temperature and Its Release

Description: The objectives of this proposed research were: 91) Separation and storage of hydrogen on nanophase diamonds. It is expected that the produced hydrogen, which will be in a mixture, can be directed to a nanophase diamond system directly, which will not only store the hydrogen, but also separate it from the gas mixture, and (2) release of the stored hydrogen from the nanophase diamond.
Date: October 13, 2008
Creator: Ghosh, Tushar K
Partner: UNT Libraries Government Documents Department

Technology and Manufacturing Readiness of Early Market Motive and Non-Motive Hydrogen Storage Technologies for Fuel Cell Applications

Description: PNNL’s objective in this report is to provide DOE with a technology and manufacturing readiness assessment to identify hydrogen storage technologies’ maturity levels for early market motive and non-motive applications and to provide a path forward toward commercialization. PNNL’s Technology Readiness Assessment (TRA) is based on a combination of Technology Readiness Level (TRL) and Manufacturing Readiness Level (MRL) designations that enable evaluation of hydrogen storage technologies in varying levels of development. This approach provides a logical methodology and roadmap to enable the identification of hydrogen storage technologies, their advantages/disadvantages, gaps and R&D needs on an unbiased and transparent scale that is easily communicated to interagency partners. The TRA report documents the process used to conduct the TRA, reports the TRL and MRL for each assessed technology and provides recommendations based on the findings.
Date: June 16, 2012
Creator: Ronnebro, Ewa
Partner: UNT Libraries Government Documents Department

A Joint Theory and Experimental Project in the Synthesis and Testing of Porous COFs for On-Board Vehicular Hydrogen Storage

Description: Conventional storage of large amounts of hydrogen in its molecular form is difficult and expensive because it requires employing either extremely high pressure gas or very low temperature liquid. Because of the importance of hydrogen as a fuel, the DOE has set system targets for hydrogen storage of gravimetric (5.5 wt%) and volumetric (40 g/L) densities to be achieved by 2015. From our continuous efforts on hydrogen storage, it is believed that metalation of highly porous solids with high-valence metals is promising and provides a rational direction to realize high volumetric hydrogen density near room temperature. This grant was focused on the study of high surface area covalent organic frameworks (COFs) with these specific objectives (1) to introduce potential metal binding sites through the COF synthesis and (2) to implement metalation experiments and evaluate their respective hydrogen adsorption properties. To maximize our efforts, simulation calculations were also performed (prior to experiments) for the prediction of binding enthalpy of hydrogen for molecular building units containing transition metals and promising COF structures to increase volumetric hydrogen uptake at room temperature. In this effort, first molecular building units with optimal binding energy for hydrogen storage (20 kJ/mol) were designed by quantum mechanical (QM) methods. Employing these results, it was revealed that one of metalated COFs takes up 60 g/L (total) of H2 at 100 bar and 298 K. To realize proposed COF structures, chemistry of COF synthesis has been developed; for instance, new air stable COFs were synthesized via hydrazone (COF-41 to 43) and imine condensation (COF-301, 320, 340, and 366) and some of them were tested the effect on metalation. Finally, a new triazine COF with high volumetric hydrogen uptake capacity was presented as a proposed future direction.
Date: June 29, 2013
Creator: Yaghi, Omar M. & Goddard, William A.
Partner: UNT Libraries Government Documents Department

Microcavity hydrogen storage. Final progress report

Description: In the microcavity storage system, high pressure hydrogen is stored in hollow, glass microspheres, 5 to 150 ..mu..m. This report presents the results of an experimental study to evaluate the performance of commercially available microspheres for this application. Eight grades were evaluated and their characteristics are presented. A substantial fraction of the microsphere beds survived the conditions of storing hydrogen at pressures of 400 atm. establishing that the concept of high pressure hydrogen storage is feasible. Information was gathered on the properties of the survivor microspheres. Processes for their selective recovery are being investigated.
Date: May 1, 1981
Creator: Teitel, R. J.
Partner: UNT Libraries Government Documents Department

Catalyzed Nano-Framework Stablized High Density Reversible Hydrogen Storage Systems

Description: A wide range of high capacity on-board rechargeable material candidates have exhibited non-ideal behavior related to irreversible hydrogen discharge / recharge behavior, and kinetic instability or retardation. This project addresses these issues by incorporating solvated and other forms of complex metal hydrides, with an emphasis on borohydrides, into nano-scale frameworks of low density, high surface area skeleton materials to stabilize, catalyze, and control desorption product formation associated with such complex metal hydrides. A variety of framework chemistries and hydride / framework combinations were investigated to make a relatively broad assessment of the method'™s potential. In this project, the hydride / framework interactions were tuned to decrease desorption temperatures for highly stable compounds or increase desorption temperatures for unstable high capacity compounds, and to influence desorption product formation for improved reversibility. First principle modeling was used to explore heterogeneous catalysis of hydride reversibility by modeling H{sub 2} dissociation, hydrogen migration, and rehydrogenation. Atomic modeling also demonstrated enhanced NaTi(BH{sub 4}){sub 4} stabilization at nano-framework surfaces modified with multi-functional agents. Amine multi-functional agents were found to have more balanced interactions with nano-framework and hydride clusters than other functional groups investigated. Experimentation demonstrated that incorporation of Ca(BH{sub 4}){sub 2} and Mg(BH{sub 4}){sub 2} in aerogels enhanced hydride desorption kinetics. Carbon aerogels were identified as the most suitable nano-frameworks for hydride kinetic enhancement and high hydride loading. High loading of NaTi(BH{sub 4}){sub 4} ligand complex in SiO{sub 2} aerogel was achieved and hydride stability was improved with the aerogel. Although improvements of desorption kinetics was observed, the incorporation of Ca(BH{sub 4}){sub 2} and Mg(BH{sub 4}){sub 2} in nano-frameworks did not improve their H{sub 2} absorption due to the formation of stable alkaline earth B12H12 intermediates upon rehydrogenation. This project primarily investigated the effect of nano-framework surface chemistry on hydride properties, while the effect of pore ...
Date: June 30, 2010
Creator: Xia Tang , Susanne M. Opalka , Daniel A. Mosher, Bruce L. Laube, Ronald J. Brown, Thomas H. Vanderspurt, Sarah Arsenault, Robert Wu, Jamie Strickler, Ewa. Ronnebro, Tim. Boyle and Joseph Cordaro
Partner: UNT Libraries Government Documents Department

REVERSIBLE HYDROGEN STORAGE IN A LiBH{sub 4}-C{sub 60} NANOCOMPOSITE

Description: Reversible hydrogen storage in a LiBH{sub 4}:C{sub 60} nanocomposite (70:30 wt. %) synthesized by solvent-assisted mixing has been demonstrated. During the solvent-assisted mixing and nanocomposite formation, a chemical reaction occurs in which the C{sub 60} cages are significantly modified by polymerization as well as by hydrogenation (fullerane formation) in the presence of LiBH{sub 4}. We have determined that two distinct hydrogen desorption events are observed upon rehydrogenation of the material, which are attributed to the reversible formation of a fullerane (C{sub 60}H{sub x}) as well as a LiBH4 species. This system is unique in that the carbon species (C{sub 60}) actively participates in the hydrogen storage process which differs from the common practice of melt infiltration of high surface area carbon materials with LiBH{sub 4} (nanoconfinment effect). This nanocomposite demonstrated good reversible hydrogen storage properties as well as the ability to absorb hydrogen under mild conditions (pressures as low as 10 bar H{sub 2} or temperatures as low as 150�C). The nanocomposite was characterized by TGA-RGA, DSC, XRD, LDI-TOF-MS, FTIR, 1H NMR, and APPI MS.
Date: August 6, 2013
Creator: Teprovich, J.; Zidan, R.; Peters, B. & Wheeler, J.
Partner: UNT Libraries Government Documents Department

Hydrogen transport and storage in engineered glass microspheres

Description: New, high strength glass microspheres filled with pressurized hydrogen exhibit densities which make them attractive for bulk hydrogen storage and transport. The membrane tensile stress at failure for our engineered glass microspheres is about 150,000 psi, permitting a threefold increase in pressure limit and storage capacity above commercial microspheres, which have been studied a decade ago and have been shown to fail at membrane stresses of 50,000 psi. Our analysis relating glass microspheres for hydrogen transport with infrastructure and economics, indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as pressurized tube transports and liquid hydrogen trailers.
Date: April 18, 1995
Creator: Rambach, G.D.
Partner: UNT Libraries Government Documents Department

Integrated Advanced Energy Systems Research at IIT

Description: This report consists of Two research projects; Sustainable Buildings and Hydrogen Storage. Sustainable Building Part includes: Wind and the self powered built environment by professor P. Land and his research group and experimental and computational works by professor D. Rempfer and his research group. Hydrogen Storage part includes: Hydrogen Storage Using Mg-Mixed Metal Hydrides by professor H. Arastoopour and his research team and Carbon Nanostructure as Hydrogen Storage Material by professor J. Prakash and his research team.
Date: September 30, 2010
Creator: Arastoopour, Hamid
Partner: UNT Libraries Government Documents Department

MODIFIED BOROHYDRIDES FOR REVERSIBLE HYDROGEN STORAGE

Description: This paper reports the results in the effort to destabilize lithium borohydride for reversible hydrogen storage. A number of metals, metal hydrides, metal chlorides and complex hydrides were selected and evaluated as the destabilization agents for reducing dehydriding temperature and generating dehydriding-rehydriding reversibility. It is found that some additives are effective. The Raman spectroscopic analysis shows the change of B-H binding nature.
Date: May 10, 2006
Creator: Au, Ming
Partner: UNT Libraries Government Documents Department

TEMPERATURE-PROGRAMMED DESORPTION: PRINCIPLES, INSTRUMENT DESIGN, AND DEMONSTRATION WITH NAALH4

Description: This article is a brief introduction to temperature-programmed desorption (TPD), an analytical technique devised to analyze, in this case, materials for their potential as hydrogen storage materials. The principles and requirements of TPD are explained and the different components of a generic TPD apparatus are described. The construction of a modified TPD instrument from commercially available components is reported together with the control and acquisition technique used to create a TPD spectrum. The chemical and instrumental parameters to be considered in a typical TPD experiment and the analytical utility of the technique are demonstrated by the dehydrogenation of titanium-doped NaAlH{sub 4} by means of thermally programmed desorption.
Date: November 7, 2006
Creator: Stowe, A & Ragaiy Zidan, R
Partner: UNT Libraries Government Documents Department

Final report for the DOE Metal Hydride Center of Excellence.

Description: This report summarizes the R&D activities within the U.S. Department of Energy Metal Hydride Center of Excellence (MHCoE) from March 2005 to June 2010. The purpose of the MHCoE has been to conduct highly collaborative and multi-disciplinary applied R&D to develop new reversible hydrogen storage materials that meet or exceed DOE 2010 and 2015 system goals for hydrogen storage materials. The MHCoE combines three broad areas: mechanisms and modeling (which provide a theoretically driven basis for pursuing new materials), materials development (in which new materials are synthesized and characterized) and system design and engineering (which allow these new materials to be realized as practical automotive hydrogen storage systems). This Final Report summarizes the organization and execution of the 5-year research program to develop practical hydrogen storage materials for light duty vehicles. Major results from the MHCoE are summarized, along with suggestions for future research areas.
Date: January 1, 2012
Creator: Keller, Jay O. & Klebanoff, Leonard E.
Partner: UNT Libraries Government Documents Department

ALUMINUM HYDRIDE, A1H3, AS A HYDROGEN STORAGE COMPOUND.

Description: Aluminum hydride is a covalent, binary hydride that has been known for more than 60 years and is an attractive medium for on-board automotive hydrogen storage, since it contains 10.1% by wt. hydrogen with a density of 1.48 g/ml. There are at least 7 non-solvated AlH{sub 3} phases, namely {alpha}, {alpha}{prime}, {beta}, {gamma}, {var_epsilon} and {zeta}. The properties of {alpha}-AlH{sub 3}, obtained from the Dow Chemical Co. in 1980, have been previously reported. Here we present a description of the thermodynamic and kinetic properties of freshly prepared {alpha}, {beta} and {gamma} phases of AlH{sub 3}. In all cases the decomposition kinetics are appreciable below 100 C and all will meet the DOE 2010 gravimetric and volumetric vehicular system targets (6 wt% H{sub 2} and 0.045 kg/L). However, further research will be required to develop an efficient and economical process to regenerate AlH{sub 3} from the spent Al powder.
Date: November 27, 2006
Creator: GRAETZ, J.; REILLY, J.; SANDROCK, G.; JOHNSON, J.; ZHOU, W.M. & WEGRZYN, J.
Partner: UNT Libraries Government Documents Department

Final Report for DOE Project Number: DE-FG02-05ER46241

Description: Hydrogen storage is the most challenging task for the hydrogen economy. We established a multidisciplinary research program for high throughput combinatorial synthesis and characterization of novel nanoporous and metastable complex hydrides, coupled to fundamental material studies including electronic, structural and kinetic transport modeling, and pump-probe experiments. Our research is based the concept of hybrid nanostructures that store hydrogen by a combination of chemi- and physorption: atomic hydrogen is stored in metastable hydrides while molecule hydrogen is stored in the nanometer pores of the hydrides. Metastable nanostructured hydride has been achieved by introducing structural and compositional disorders through high throughput elemental substitution/doping, catalyst addition, and nonequilibrium processing. Fast screening compatible with the combinatorial synthesis was achieved by combining X-ray structural characterization with the development of a laser-based microbalance. Manufacturing of nanoporous metahydrides that are identified as promising by the combinatorial synthesis has been explored along with the materials search.
Date: March 15, 2010
Creator: Chen, Gang; Dresselhaus, Mildred S.; Grigoropoulos, Costas P.; Mao, Samuel S.; Xiang, Xiaodong & Zeng, Taofang
Partner: UNT Libraries Government Documents Department

Final Report for the DOE-BES Program Mechanistic Studies of Activated Hydrogen Release from Amine-Boranes

Description: Effective storage of hydrogen presents one of the most significant technical gaps to successful implementation of the hydrogen economy, particularly for transportation applications. Amine boranes, such as ammonia borane H3NBH3 and ammonia triborane H3NB3H7, have been identified as promising, high-capacity chemical hydrogen storage media containing potentially readily released protic (N-H) and hydridic (B-H) hydrogens. At the outset of our studies, dehydrogenation of ammonia borane had been studied primarily in the solid state, but our DOE sponsored work clearly demonstrated that ionic liquids, base-initiators and/or metal-catalysts can each significantly increase both the rate and extent of hydrogen release from amine boranes under moderate conditions. Our studies also showed that depending upon the activation method, hydrogen release from amine boranes can occur by very different mechanistic steps and yield different types of spent-fuel materials. The fundamental understanding that was developed during this grant of the pathways and controlling factors for each of these hydrogen-release mechanisms is now enabling continuing discovery and optimization of new chemical-hydride based hydrogen storage systems.
Date: January 13, 2013
Creator: Sneddon, Larry G. & Baker, R. Thomas
Partner: UNT Libraries Government Documents Department

Hydrogen Storage in Metal-Organic Frameworks

Description: Conventional storage of large amounts of hydrogen in its molecular form is difficult and expensive because it requires employing either extremely high pressure gas or very low temperature liquid. Because of the importance of hydrogen as a fuel, the DOE has set system targets for hydrogen storage of gravimetric (5.5 wt%) and volumetric (40 g L-1) densities to be achieved by 2015. Given that these are system goals, a practical material will need to have higher capacity when the weight of the tank and associated cooling or regeneration system is considered. The size and weight of these components will vary substantially depending on whether the material operates by a chemisorption or physisorption mechanism. In the latter case, metal-organic frameworks (MOFs) have recently been identified as promising adsorbents for hydrogen storage, although little data is available for their sorption behavior. This grant was focused on the study of MOFs with these specific objectives. (1) To examine the effects of functionalization, catenation, and variation of the metal oxide and organic linkers on the low-pressure hydrogen adsorption properties of MOFs. (2) To develop a strategy for producing MOFs with high surface area and porosity to reduce the dead space and increase the hydrogen storage capacity per unit volume. (3) To functionalize MOFs by post synthetic functionalization with metals to improve the adsorption enthalpy of hydrogen for the room temperature hydrogen storage. This effort demonstrated the importance of open metal sites to improve the adsorption enthalpy by the systematic study, and this is also the origin of the new strategy, which termed isoreticular functionalization and metalation. However, a large pore volume is still a prerequisite feature. Based on our principle to design highly porous MOFs, guest-free MOFs with ultrahigh porosity have been experimentally synthesized. MOF-210, whose BET surface area is 6240 m2 g-1 (the ...
Date: April 26, 2012
Creator: Yaghi, Omar M.
Partner: UNT Libraries Government Documents Department

Hydrogen Storage at Ambient Temperature by the Spillover Mechanism

Description: The goal of this project was to develop new nanostructured sorbent materials, using the hydrogen spillover mechanism that could meet the DOE 2010 system targets for on-board vehicle hydrogen storage. Hydrogen spillover may be broadly defined as the transport (i.e., via surface diffusion) of dissociated hydrogen adsorbed or formed on a first surface onto another surface. The first surface is typically a metal (that dissociates H2) and the second surface is typically the support on which the metal is doped. Hydrogen spillover is a well documented phenomenon in the catalysis literature, and has been known in the catalysis community for over four decades, although it is still not well understood.1, 2 Much evidence has been shown in the literature on its roles played in catalytic reactions. Very little has been studied on hydrogen storage by spillover at ambient temperature. However, it is also known to occur at such temperature, e.g., direct evidence has been shown for spillover on commercial fuel-cell, highly dispersed Pt/C, Ru/C and PtRu/C catalysts by inelastic neutron scattering.3 To exploit spillover for storage, among the key questions are whether spillover is reversible at ambient temperature and if the adsorption (refill) and desorption rates at ambient temperature are fast enough for automotive applications. In this project, we explored new sorbents by using a transition metal (e.g., Pt, Ru, Pd and Ni) as the H2 dissociation source and sorbents as the hydrogen receptor. The receptors included superactivated carbons (AX-21 and Maxsorb), metal organic frameworks (MOFs) and zeolites. Different metal doping methods have been used successfully to achieve high metal dispersion thereby allowing significant spillover enhancements, as well as a bridging technique used for bridging to MOFs. Among the metals tested, Pt is the hardest to achieve high metal dispersion (and consequently spillover) while Ru is the easiest to disperse. ...
Date: February 4, 2011
Creator: Yang , Ralph T.
Partner: UNT Libraries Government Documents Department

Amineborane Based Chemical Hydrogen Storage - Final Report

Description: The development of efficient and safe methods for hydrogen storage is a major hurdle that must be overcome to enable the use of hydrogen as an alternative energy carrier. The objectives of this project in the DOE Center of Excellence in Chemical Hydride Storage were both to develop new methods for on-demand, low temperature hydrogen release from chemical hydrides and to design high-conversion off-board methods for chemical hydride regeneration. Because of their reactive protic (N-H) and hydridic (B-H) hydrogens and high hydrogen contents, amineboranes such as ammonia borane, NH3BH3 (AB), 19.6-wt% H2, and ammonia triborane NH3B3H7 (AT), 17.7-wt% H2, were initially identified by the Center as promising, high-capacity chemical hydrogen storage materials with the potential to store and deliver molecular hydrogen through dehydrogenation and hydrolysis reactions. In collaboration with other Center partners, the Penn project focused both on new methods to induce amineborane H2-release and on new strategies for the regeneration the amineborane spent-fuel materials. The Penn approach to improving amineborane H2-release focused on the use of ionic liquids, base additives and metal catalysts to activate AB dehydrogenation and these studies successfully demonstrated that in ionic liquids the AB induction period that had been observed in the solid-state was eliminated and both the rate and extent of AB H2-release were significantly increased. These results have clearly shown that, while improvements are still necessary, many of these systems have the potential to achieve DOE hydrogen-storage goals. The high extent of their H2­-release, the tunability of both their H2 materials weight-percents and release rates, and their product control that is attained by either trapping or suppressing unwanted volatile side products, such as borazine, continue to make AB/ionic­-liquid based systems attractive candidates for chemical hydrogen storage applications. These studies also demonstrated that H2-­release from chemical hydrides can occur by a number of different ...
Date: April 21, 2011
Creator: Sneddon, Larry G.
Partner: UNT Libraries Government Documents Department