High capacity hydrogenstorage materials: attributes for automotive applications and techniques for materials discovery

Abstract

Widespread adoption of hydrogen as a vehicular fuel depends critically upon the ability to store hydrogen on-board at high volumetric and gravimetric densities, as well as on the ability to extract/insert it at sufficiently rapid rates. As current storage methods based on physical means-high-pressure gas or (cryogenic) liquefaction-are unlikely to satisfy targets for performance and cost, a global research effort focusing on the development of chemical means for storing hydrogen in condensed phases has recently emerged. At present, no known material exhibits a combination of properties that would enable high-volume automotive applications. Thus new materials with improved performance, or new approaches to the synthesis and/or processing of existing materials, are highly desirable. In this critical review we provide a practical introduction to the field of hydrogen storage materials research, with an emphasis on (i) the properties necessary for a viable storage material, (ii) the computational and experimental techniques commonly employed in determining these attributes, and (iii) the classes of materials being pursued as candidate storage compounds. Starting from the general requirements of a fuel cell vehicle, we summarize how these requirements translate into desired characteristics for the hydrogen storage material. Key amongst these are: (a) high gravimetric and volumetric hydrogen density, (b) thermodynamics that allow for reversible hydrogen uptake/release under near-ambient conditions, and (c) fast reaction kinetics. To further illustrate these attributes, the four major classes of candidate storage materials-conventional metal hydrides, chemical hydrides, complex hydrides, and sorbent systems-are introduced and their respective performance and prospects for improvement in each of these areas is discussed. Finally, we review the most valuable experimental and computational techniques for determining these attributes, highlighting how an approach that couples computational modeling with experiments can significantly accelerate the discovery of novel storage materials (155 references).

Towards Versatile and Sustainable Hydrogen Production through Electrocatalytic Water Splitting: Electrolyte Engineering

“…One of the promising solutions towards this issue is the electrocatalytic conversion to produce energy carriers. In this context, hydrogen has attracted tremendous attention in this decade4, 5, 6, 7 owing to its extremely high energy density (H 2 : 120 MJ kg −1 and gasoline: 44 MJ kg −1 ) 4, 5…”

The role of Ni in increasing the reversibility of the hydrogen release from nanoconfined LiBH4

“…Alternatively, reversible hydrogen storage in porous solids or metal hydrides is considered, offering advantages in terms of safety and volumetric hydrogen content. 1,2 One of the materials that is extensively being investigated is lithium borohydride (LiBH 4 ) which has a gravimetric and volumetric hydrogen content of 18.5 wt% and 121 kg H 2 m À3 respectively, making it attractive for hydrogen storage a Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands. E-mail: P.E.deJongh@uu.nl; Fax: +31 30 251 1027; Tel: +31 30 253 6766 for cars.…”

Prediction of a Ca(BH4)(NH2) quaternary hydrogen storage compound from first-principles calculations

“…The change in free energy, ∆G, is negative in both reactions and also quantitatively similar, with values of -90.1 kJ/mol H 2 and -72.2 and kJ/mol H 2 at T = 300 K for reaction (1) and (3) respectively.…”

“…In search of this material, various material classes have been proposed as candidates such as conventional metal hydrides, complex hydrides, sorbents and chemical hydrides. 1,2,3,4,5,6,7,8,9,10 Although materials in these classes often possess some of the desired properties, a single material that encompasses all of them has remained undiscovered.…”