Hydrogen Storage: State-of-the-Art and Future Perspective.

Abstract not availableJRC.F-Institute for Energy (Petten

Determination of saturated film densities and volumes for adsorbed hydrogen, and application to the calculation of the enthalpy of adsorption at room temperature

The development of high-performance materials for hydrogen storage by physical adsorption requires understanding of detailed microscopic properties of the adsorbed film. In this work, we show that adsorbed hydrogen films in activated carbons have saturation densities [about]100 g/L, well in excess of liquid hydrogen, and remarkably independent of sample characteristics and temperature (a property of the adsorbate only). We propose a reliable method to determine the volume of the adsorbed film at cryogenic or room temperatures by extrapolation of the low-coverage adsorption isotherms using the Ono-Kondo model and the saturation film density as a fixed point. Remarkably, film volumes are only [about]40% or [about]12% of the total pore volume at 77 K and 296 K, respectively (the reduction of pore volume with temperature is explained in terms of population of adsorption sites of different depths). By reliably determining the film volume, absolute adsorption isotherms for an activated carbon are calculated at 273 K and 296 K and used with the Clausius-Clapeyron relation to obtain the enthalpy of adsorption (8.3 kJ/mol, within 1.2% agreement of the low-coverage cryogenic determination for the same adsorbent, in concordance with the fact that at high temperatures deeper adsorption sites are dominant). This methodology should facilitate reliable calculations of the enthalpy of adsorption for room temperatures for weakly adsorbing gases. This report presents the first investigation of a 5.3-liter tank, filled with 2.86 kg of University of Missouri monolithic carbon, under operation at 23 [degree]C (room temperature), 0 [degree]C (ice bath), and -79 [degree]C (dry-ice bath) and pressures 0-100 bar. Storage and fast charge/discharge data, including temperature and pressure profiles as a function of time are reported. These storage data agree within 2% of small-scale measurements on the commercial instrument, Hiden HTP1-V. Remarkably, the tank can be filled in 3-5 minutes, the DOE target for 2020 and later. The table below shows that there is a large temperature rise and drop, of 30-50 [degree]C, during filling and discharging even at room temperature. These are unexpectedly large temperature excursions because binding of H[2] on carbon, with a typical heat of adsorption of 5.0 kJ/mol (H[2] on graphite), is considered weak and a source of major temperature excursions only at liquid nitrogen temperature. It shows, as expected, that equilibration is faster at high temperature than at low temperature.Includes bibliographical reference

Designing an Ab2-type alloy (TIZr-CrMNMO) for the hybrid hydrogen storage concept

The hybrid hydrogen storage method consists of the combination of both solid-state metal hydrides and gas hydrogen storage. This method is regarded as a promising trade-off solution between the already developed high-pressure storage reservoir, utilized in the automobile industry, and solid-state storage through the formation of metal hydrides. Therefore, it is possible to lower the hydrogen pressure and to increase the hydrogen volumetric density. In this work, we design a non-stoichiometric AB2 C14-Laves alloy composed of (Ti0.9Zr0.1)1.25Cr0.85Mn1.1Mo0.05. This alloy is synthesized by arc-melting, and the thermodynamic and kinetic behaviors are evaluated in a high-pressure Sieverts apparatus. Proper thermodynamic parameters are obtained in the range of temperature and pressure from 3 to 85 ◦C and from 15 to 500 bar: ∆Habs. = 22 ± 1 kJ/mol H2, ∆Sabs. = 107 ± 2 J/K mol H2, and ∆Hdes. = 24 ± 1 kJ/mol H2, ∆Sdes. = 110 ± 3 J/K mol H2. The addition of 10 wt.% of expanded natural graphite (ENG) allows the improvement of the heat transfer properties, showing a reversible capacity of about 1.5 wt.%, cycling stability and hydrogenation/dehydrogenation times between 25 to 70 s. The feasibility for the utilization of the designed material in a high-pressure tank is also evaluated, considering practical design parameters.Fil: Puszkiel, Julián Atilio. Helmholtz-zentrum Geesthacht; Alemania. Instituto de Investigaciones Energéticas de Cataluña; España. Comisión Nacional de Energía Atómica. Gerencia de Área de Aplicaciones de la Tecnología Nuclear. Gerencia de Investigación Aplicada CAB. Departamento Fisicoquímica de Materiales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Bellosta von Colbe, José M.. Helmholtz-zentrum Geesthacht; AlemaniaFil: Jepsen, Julian. Helmholtz-zentrum Geesthacht; Alemania. Helmut Schmidt University; AlemaniaFil: Mitrokhin, Sergey V.. Lomonosov Moscow State University; RusiaFil: Movlaev, Elshad. Lomonosov Moscow State University; RusiaFil: Verbetsky, Victor. Lomonosov Moscow State University; RusiaFil: Klassen, Thomas. Helmholtz-zentrum Geesthacht; Alemania. Helmut Schmidt University; Alemani

Robustness and Thermophysical Properties of MOF-5: A Prototypical Hydrogen Storage Material.

MOF-5 has attracted considerable attention due to its ability to store gaseous fuels at low pressure with high densities. However, low thermal conductivity and limited robustness upon exposure to water and other reactive species are two challenges which limit the application of MOF-5. The focus of this dissertation is to understand and overcome these shortcomings through detailed experimental and computational characterization of the prototype compound, MOF-5. Improvements to the thermal conductivity of MOF-5 are demonstrated using densified pellets consisting of a physical mixture of MOF-5 and expanded natural graphite (ENG). We conclude that the low thermal conductivity typical of MOFs can be improved using a judicious combination of second phase additions and processing techniques. Regarding robustness, we first quantify experimentally the impact of humid air exposure on the properties of MOF-5 as a function of exposure time, humidity level, and morphology (i.e., powders vs. pellets). Densification into pellets can slow the degradation of MOF-5 significantly, and may present a pathway to enhance the stability of some MOFs. We subsequently examined the thermodynamics and kinetics of water adsorption/insertion into MOF-5 using van der Waals-augmented DFT calculations and transition state finding techniques. We find that incoming water molecules preferentially adsorb at adjacent sites on Zn-O clusters rather than filling widely separated low energy sites. Our calculations also suggest that the thermodynamics of MOF hydrolysis are coverage dependent, and that hydrolysis is slow at low water coverages and is preceded by an incubation period. The third component in our study of MOF-5 robustness involved cyclic and static exposure to impure hydrogen gas. MOF-5 was exposed to 5 gas mixtures over hundreds of adsorption/desorption pressure cycles and for extended periods of static exposure lasting up to 1 week. Hydrogen chloride was the only impurity that yielded a measurable decrease in hydrogen storage capacity. FTIR and XRD analyses reveal slight changes in the spectra only for those samples exposed to HCl and NH3 impurities. In closing, we briefly examine hydrogen permeation into- and the internal structure of- MOF-5 pellets using neutron and x-ray imaging techniques (tomography and radiography).PhDPhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/116759/1/qfming_1.pd

Computational studies of gases adsorbed on graphene-like materials

Nanoporous activated carbons generate interest for their gas storage and separation potential. Generally, adsorbents are assumed rigid, even though they are formed by feeble quasi-2D flakes of graphene. In 2019, Schaeperkoetter et al.^1 observed swelling of graphene oxide frameworks (GOFs) upon supercritical adsorption of various gases. We performed molecular dynamics (MD) simulations of methane and xenon in various models of GOF's with interaction parameters derived from ab initio Density Functional Theory. We observe a monotonic increase of the interlayer spacing consistent with experiments only for a model of benzene-1,4-diboronic acid (DBA) molecules bonded covalently to graphene on both sides of the pore at random orientations, establishing the structure of the DBA-GOFs. Adsorbents are also useful for the separation of gases, e.g., methane and carbon dioxide from organic waste biogas. We performed MD and grand canonical Monte Carlo simulations of the coadsorption of CH4 and CO2 in pores of different sizes and surface functionalization. We observe significant selectivity for the adsorption of CO2 - potentiated by the presence of polar surface groups and determined optimal conditions for gas separation in this system. Finally, atomically flat graphene allows the emergence of two-dimensional films of weakly adsorbed helium with interesting quantum properties. We performed ab initio 2nd order Moller-Plesset calculations with large basis sets of the interaction of 1, 2, and 3 He atoms on graphene-like systems. The interaction parameters are then used in the Bose-Hubbard model, and under certain conditions it is predicted that superfluid or Mott insulating phases can occur.Includes bibliographical references

Hydrogen energy systems : development and application of modelling tools

This paper deals with the modelling and optimisat ion of a series of typical hydrogen systems. The systems models have been developed on the TRNSYS 1 platform. The mathematical models and the methodology used for analysis are de scribed in this paper, as well as the validation of the models. An application on an island in Norway is also presented

Research and development of hydrogen carrier based solutions for hydrogen compression and storage

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMIndustrial and public interest in hydrogen technologies has risen strongly recently, as hydrogen is the ideal means for medium to long term energy storage, transport and usage in combination with renewable and green energy supply. In a future energy system, the production, storage and usage of green hydrogen is a key technology. Hydrogen is and will in future be even more used for industrial production processes as a reduction agent or for the production of synthetic hydrocarbons, especially in the chemical industry and in refineries. Under certain conditions material based systems for hydrogen storage and compression offer advantages over the classical systems based on gaseous or liquid hydrogen. This includes in particular lower maintenance costs, higher reliability and safety. Hydrogen storage is possible at pressures and temperatures much closer to ambient conditions. Hydrogen compression is possible without any moving parts and only by using waste heat. In this paper, we summarize the newest developments of hydrogen carriers for storage and compression and in addition, give an overview of the different research activities in this fiel

Research and development of hydrogen carrier based solutions for hydrogen compression and storage

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Cleaning and surface properties

Principles of precision cleaning for ultra high vacuum applications are reviewed together with the techniques for the evaluation of surface cleanliness. Methods to verify the effectiveness of cleaning procedures are discussed. Examples are presented to illustrate the influence of packaging and storage on the recontamination of the surface after cleaning. Finally, the effect of contamination on some relevant surface properties, like secondary electron emission and wettability is presented