Bulletin of the American Physical Society
2009 APS March Meeting
Volume 54, Number 1
Monday–Friday, March 16–20, 2009; Pittsburgh, Pennsylvania
Session V5: Computational Design of Hydrogen Storage Materials |
Hide Abstracts |
Sponsoring Units: FIAP Chair: Chris Van de Walle, University of California, Santa Barbara Room: 401/402 |
Thursday, March 19, 2009 8:00AM - 8:36AM |
V5.00001: Computational Discovery of Novel Hydrogen Storage Materials and Reactions Invited Speaker: Practical hydrogen storage for mobile applications requires materials that exhibit high hydrogen densities, low decomposition temperatures, and fast kinetics for absorption and desorption. Unfortunately, no reversible materials are currently known that possess all of these attributes. Here we present an overview of our recent efforts aimed at developing a first-principles computational approach to the discovery of novel hydrogen storage materials. We have developed computational tools which enable accurate prediction of decomposition thermodynamics, crystal structures for unknown hydrides, and thermodynamically preferred decomposition pathways. We present examples that illustrate each of these three capabilities. Specifically, we focus on recent work on crystal structure and dehydriding reactions of borohydride materials, such as Mg(BH$_4$)$_2$, MgB$_{12}$H$_{12}$, and mixtures of complex hydrides such as the ternary LiBH$_4$/LiNH$_2$/MgH$_2$ system.\\ \\ {\textbf References:}\\[0pt] (1) V. Ozolins, E. H. Majzoub, and C. Wolverton, ``First-Principles Prediction of a Ground State Crystal Structure of Magnesium Borohydride'', Phys. Rev. Lett. {\textbf 100}, 135501 (2008).\\ (2) C. Wolverton, D. J. Siegel, A. R. Akbarzadeh, and V. Ozolins, ``Discovery of Novel Hydrogen Storage Materials: An Atomic Scale Computational Approach'', J. Phys. Condens. Matt. {\textbf 20}, 064228 (2008).\\ (3) J. Yang, et al., ``A Self-Catalyzing Hydrogen Storage Material'' Angew. Chem. Int. Ed., {\textbf 47}, 882 (2008).\\ (4) A. R. Akbarzadeh, V. Ozolins, and C. Wolverton, ``First-Principles Determination of Multicomponent Hydride Phase Diagrams: Application to the Li-Mg-N-H System'', Advanced Materials {\textbf 19}, 3233 (2007).\\ (5) D. J. Siegel, C. Wolverton, and V. Ozolins, ``Thermodynamic Guidelines for the Prediction of Hydrogen Storage Reactions and their Application to Destabilized Hydride Mixtures'', Phys. Rev. B {\textbf 76}, 134102 (2007). [Preview Abstract] |
Thursday, March 19, 2009 8:36AM - 9:12AM |
V5.00002: Combining computation and experiment to accelerate the discovery of new hydrogen storage materials Invited Speaker: The potential of emerging technologies such as fuel cells (FCs) and photovoltaics for environmentally-benign power generation has sparked renewed interest in the development of novel materials for high density energy storage. For applications in the transportation sector, the demands placed upon energy storage media are especially stringent, as a potential replacement for fossil-fuel-powered internal combustion engines -- namely, the proton exchange membrane FC -- utilizes hydrogen as a fuel. Although hydrogen has about three times the energy density of gasoline by weight, its volumetric energy density (even at 700 bar) is roughly a factor of six smaller. Consequently, the safe and efficient storage of hydrogen has been identified as one of the key materials-based challenges to realizing a transition to FC vehicles. This talk will present an overview of recent efforts at Ford aimed at developing new materials for reversible, solid state hydrogen storage. A tight coupling between first-principles modeling and experiments has greatly accelerated our efforts, and several examples illustrating the benefits of this approach will be presented. [Preview Abstract] |
Thursday, March 19, 2009 9:12AM - 9:48AM |
V5.00003: Novel hydrogen storage approaches using organometallics Invited Speaker: Storing molecular hydrogen in organometallics can ensure fast kinetics, low heat management, high energy efficiency, and superb reversibility. The gravimetric density is, however, low for room temperature storage. The reason for the too low density is because the binding is too weak. First-principles calculations [1,2] suggested that organometallics may significantly increase the binding, which is also correlated with decreasing inter-molecular distances and hence a significantly increased volumetric density [3]. Current experimental difficulties are twofold: a) how to synthesize the organometallics and b) how to avoid the transition metal atoms from clustering [4]? Recent experiment [5] on titanium- doped porous silica and theoretical predictions on calcium doping [3,6] may shed new lights on these difficult problems. \newline [1] Y. Zhao, et al., Phys. Rev. Lett.\textbf{ 94}, 155504 (2005). \newline [2] T. Yildirim and S. Ciraci, Phys. Rev. Lett. \textbf{94}, 175501 (2005). \newline [3] Y.-H. Kim, Y. Y. Sun, and S. B. Zhang, unpublished. \newline [4] Q. Sun, et al., J. Am. Chem. Soc., \textbf{127}, 14582 (2005). \newline [5] A. Hamaed, et al., J. Am. Chem. Soc. \textbf {130}, 6992 (2008). \newline [6] M. Yoon, et al., Phys. Rev. Lett. \textbf{100}, 206806 (2008). [Preview Abstract] |
Thursday, March 19, 2009 9:48AM - 10:24AM |
V5.00004: Computational methods to determine the structure of hydrogen storage materials Invited Speaker: To understand the mechanisms and thermodynamics of material-based hydrogen storage, it is important to know the structure of the material and the positions of the hydrogen atoms within the material. Because hydrogen can be difficult to resolve experimentally computational research has proven to be a valuable tool to address these problems. We discuss different computational methods for identifying the structure of hydrogen materials and the positions of hydrogen atoms, and we illustrate the methods with specific examples. Through the use of ab-initio molecular dynamics, we identify molecular hydrogen binding sites in the metal-organic framework commonly known as MOF-5 [1]. We present a method to identify the positions of atomic hydrogen in imide structures using a novel type of effective Hamiltonian. We apply this new method to lithium imide (Li$_{2}$NH), a potentially important hydrogen storage material, and demonstrate that it predicts a new ground state structure [2]. We also present the results of a recent computational study of the room-temperature structure of lithium imide in which we suggest a new structure that reconciles the differences between previous experimental and theoretical studies. \\[4pt] [1] T. Mueller and G. Ceder, Journal of Physical Chemistry B 109, 17974 (2005). \\[0pt] [2] T. Mueller and G. Ceder, Physical Review B 74 (2006). [Preview Abstract] |
Thursday, March 19, 2009 10:24AM - 11:00AM |
V5.00005: Kinetics of bulk and surface mass transport in complex metal hydrides Invited Speaker: Metal hydrides can be used to store hydrogen in high gravimetric and volumetric densities. However, the kinetics of hydrogen release and uptake are slow in complex metal hydrides. Clarification of the mechanism of hydrogen release and uptake in complex metal hydrides can aid in a rational design of new hydrogen storage materials with fast kinetics or catalysts that will catalyze the rate of hydrogen release from the existing materials. The release of hydrogen in metal hydrides requires the transport of hydrogen and/or heavier species. The kinetics of such mass transport in metal hydrides can be the rate-limiting process for the release of hydrogen. For example, the rate-determining step for the release of hydrogen from NaAlH4 is the creation and diffusion of neutral AlH3 defects in NaAlH4. The release of hydrogen from LiH destabilized LiNH2 also proceeds via the creation of neutral point defects. The mechanism of mass transport in prototypical hydrogen storage materials such as NaAlH4 and LiNH2 and the mechanism of hydrogen diffusion in aluminum will be discussed. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700