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HYDRIDES FOR ENERGY STORAGE
Proceedings of an International Symposium held
in Geilo, Norway, 14 - 19 August 1977
Edited by
A. F. ANDRESEN
Institutt for Atomenergi, Kjeller, Norway
and
A. J. MAELAND
Allied Chemical Corporation, Morristown, N.J., U.S.A.
ORGANIZED BY
The Netherlands Norwegian Reactor School,
Institutt for Atomenergi, Kjeller, Norway
Published on behalf of the
INTERNATIONAL ASSOCIATION
FOR HYDROGEN ENERGY
by'
PERGAMON PRESS
OXFORD NEW YORK · TORONTO · SYDNEY · PARIS · FRANKFURT
U.K. Pergamon Press Ltd., Headington Hill Hall,
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FEDERAL REPUBLIC Pergamon Press GmbH, 6242 Kronberg-Taunus,
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Copyright © 1978 International Association for Hydrogen Energy
All Rights Reserved. No part of this publication may be reproduced, stored in a
retrieval system or transmitted in any form or by any means: electronic, electro
static, magnetic tape, mechanical, photocopying, recording or otherwise, without
permission in writing from the copyright holders.
First edition 1978
British Library Cataloguing in Publication Data
Hydrides for energy storage.
1. Hydrogen as Fuel - Congresses 2. Hydrogen - Storage
- Congresses 3. Metal hydrides - Industrial
applications - Congresses
I. Andresen, A F II. Maeland, A J
III. Netherlands - Norwegian Reactor School
65'.81 TP359.H8 78-40501
ISBN 0-08-022715-5
In order to make this volume available as economically and as rapidly as possible the
authors ' typescripts have been reproduced in their original forms. This method
unfortunately has its typographical limitations but it is hoped that they in no way
distract the reader.
Printed in Great Britain by William Clowes & Sons Limited
London, Beccles and Colchester
FOREWORD
Hydrogen is considered as one of the most promising fuels for the
future. It is non-polluting, fully recycleable and has an almost
unlimited supply potential. It can be distributed through pipe
lines or stored in containers for automotive use. However, the con
ventional means of hydrogen storage has serious short-comings.
Pressure cylinders are heavy, expensive and volume demanding. Lique
faction is energy consuming and require complicated cryogenic equip
ment. In both cases the safety aspects pose serious problems.
It has long been known that many hydrides contain more hydrogen per
unit volume than liquid or even solid hydrogen. Some alloy systems
absorb and release hydrogen at room temperature at pressures close
to atmospheric pressure. Indeed, metal hydrides offer a reversible
chemical means for storing and supplying hydrogen which can con
veniently be used for both mobile and stationary purposes. For
several years extensive research has been carried out in many labo
ratories to find suitable alloy systems. However, a fully satis
factory system has not yet been found. All the reported hydrides
suffer at least one of the following drawbacks: Too low a ratio
between hydrogen and metal weight, too costly metals involved, the
absorption or release of hydrogen is difficult and slow or sensitive
to poisoning phenomena.
The intention with this symposium was to bring together research
workers active, either from a practical or fundamental point of view,
in the field of hydrides. By discussing the fundamental properties
of hydrides we intended to stress the possibilities and limitations
which exist and possibly bring out new ideas for future research.
With the wide range of activities now being carried out in this field,
we felt that there was a need for a survey of the activities and a
review of the present state of the art.
IX
SYMPOSIUM COMMITTEES
Programme Committee;
A.F. Andresen
Institutt for Atomenergi
P.O.B. 40, 2007 Kjeller
Norway
T.B. Flanagan
University of Vermont
Burlington, Vermont 05401
USA
G.G. Libowitz
Allied Chemical Corp.
P.O.B. 1021R
Morristown, N.J. 07960
USA
A.J. Maeland
Allied Chemical Corp.
P.O.B. 1021R
Morristown, N.J. 07960
USA
H.H. van Mai
1
N.V. Philips Gloeilampenfabrieken
Eindhoven
The Netherlands
K. Videm
Institutt for Atomenergi
P.O.B. 40, 2007 Kjeller
Norway
Organizing Committee:
E. Andersen
The Netherlands-Norwegian Reactor School
Institutt for Atomenergi
P.O.B. 40, 2007 Kjeller
Norway
A.F. Andresen
Institutt for Atomenergi
P.O.B. 40, 2007 Kjeller
Norway
G. Jarrett
The Netherlands-Norwegian Reactor School
Institutt for Atomenergi
P.O.B. 40, 2007 Kjeller
Norway
xi
ACKNOWLEDGEMENTS
The symposium commitees gratefully acknowledge the financial support
and services rendered by Institutt for atomenergi, Kjeller, Norway
They are also grateful to Allied Chemical Corporation, New Jersey,
U.S.A., for financial support. These proceedings were published
under a grant from the United States Department of Energy, Washing
ton, D.C., U.S.A.
Thanks are also due to all the invited speakers and the other lec
turers for their cooperation in preparing the manuscripts.
XI11
LIST OF PARTICIPANTS
Achard, J.C., Equipe de Chimie Métallurgique, Bellevue-Meudon, France
Angus, H.C., INCO Europe Ltd., Birmingham, U.K.
Bergsma, J., Netherlands Energy Research Foundation, Petten (NH)
The Netherlands
Bowman, R.C.,Jr., Monsanto Research Corp., Miamisburg, Ohio, U.S.A.
Bronger, W., Inst. für Anorganische Chemie, Achen, West-Germany
Buchner, H., Daimler-Benz AG, Stuttgart, West-Germany
Busch, G.A., Lab. of Solid State Physics ETH, Zürich, Switzerland
Buschow, K.H.J., Philips Research Labs., Eindhoven, The Netherlands
Cannon, J.G., Molycorp Inc., White Plains, N.Y., USA
Darriet, B., Lab. de Chimie du Solide, Université de Bordeaux, France
Davidov, D., Racah Inst. for Physics, Hebrew University, Jerusalem,
Israel
Didisheim, J.J., Lab. de Cristallographie, Université de Geneve,
Switzerland
Douglass, D.L., Boelter Hall, University of Cal., Los Angeles, U.S.A.
van Essen, R.M., Philips Research Labs., Eindhoven, The Netherlands
Flanagan, T.B., Dept. of Chemistry, University of Vermont, Burlington,
Vermont, U.S.A.
Furrer, A., Inst. für Reaktortechnik ETHZ, Würenlingen, Switzerland
Gelatt, CD., Pierce Hall, Harward University, Cambridge, Mass., U.S.A
Halstead, T.K., Dept. of Chemistry, University of York, U.K.
Harris, I.R., Dept. of Phys. Metallurgy and Science of Materials,
University of Birmingham, U.K.
Hempelmann, R., Westfälische Wilhelms-Universität, Inst, für Phys.
Chemie, Münster, West-Germany
Kleppa, O.J., The James Franck Institute, Chicago, 111., U.S.A.
Korn, C , Dept. of Physics, Ben Gurion University, Beer Sheva, Israel
Libowitz, G.G., Allied Chemical Corp., Morristown, N.J., U.S.A.
Lewis, D., AB Atomenergi, Nyköping, Sweden
Lewis, F.A., Chemistry Dept., Queens University, Belfast, Northern
Ireland, U.K.
Lundin, C , Denver Research Institute, University of Denver, Col., U.S
Maeland, A.J., Allied Chemical Corp., Morristown, N.J., U.S.A.
1
van Mal, H.H., N.V. Philips Gloeilampenfabrieken, Eindhoven, The
Netherlands
Meier, M., Inst. für Anorganische Chemie der TH, Achen, West-Germany
Mintz, M.H., Dept. of Nuclear Engineering, Ben Gurion University,
Beer Sheva, Israel
Müller, P., Inst. für Anorganische Chemie der TH, Achen, West-Germany
Northrup,0.J.M., Jr., Chemical Technology Div., Sandia Labs.,
Albuquerque, N.M., U.S.A.
Otnes, K., Institutt for atomenergi, Kjeller, Norway
Pedersen, B., Dept. of Chemistry, University of Oslo, Norway
Pernestâl, K., Inst. of Physics, University of Uppsala, Sweden
de Pous, 0., Batelle Institute, Carouge, Switzerland
Radelaar, S., Inst. of Physics, University of Utrecht, The Netherlands
Rebiere, J., C.E.N.G., Lab. A.S.P., Grenoble, France
Reilly, J.J., Dept. of Applied Science, Brookhaven National Lab.,
Upton, L.I., N.Y., U.S.A.
XV
xvi List of Participants
1
van Rijswick, M. , Philips Research Labs., Eindhoven, The Netherlands
Ron., M., Dept. of Materials Engineering, TECHNION, Haifa, Israel
Sandrock, G., The International Nickel Co., Inc., Sterling Forest,
Suffern, N.Y.,U.S.A.
Stohrer, H., Daimler-Benz AG, Stuttgart, West-Germany
Schlapbach, L., Lab. für Festkörperforschung, ETH, Zurich, Switzerland
Sheft, I., Chemistry Div., Argonne Nat. Lab., Argonne 111., U.S.A.
Slotfeldt-Ellingsen, D., Central Inst. for Industrial Research, Oslo,
Norway
Suda, J., Kogakuin University, Tokyo, Japan
S0rensen, 0. Toft, Research Establishment Ris0, Roskilde, Denmark
Venema, W., Natuurkundig Lab., Vrije Universiteit, Amsterdam, The
Netherlands
Videm, K., Institutt for atomenergi, Kjeller, Norway
Vigeholm, B., Research Establishment Ris0, Roskilde, Denmark
von Waldkirch, Th., Eid. Technische Hochschule,Zürich, Switzerland
Wallace, W.E., Dept. of Chemistry, University of Pittsburgh, Pa., U.S,A.
Weaver, H.T., Org. 2354, Sandia Labs., Albuquerque, N.M., U.S.A.
Wenzl, H., Inst. für Festkörperforschung, KFA, Julien, West-Germany
Yamadaya, T., Matsushita Research Institute Tokyo Inc., Kawasaki, Japan
THE PROSPECTS OF HYDROGEN AS AN
ENERGY CARRIER FOR THE FUTURE
George G. Libowitz
Materials Research Center, Allied Chemical Corporation
Morristown, New Jersey, U.S.A. 07960
ABSTRACT
In order to evaluate the possibilities of achieving a "Hydrogen
Economy", scientific problems involved in the production, storage,
transmission, and utilization of hydrogen are discussed. This in
cludes such topics as catalysis, solid state electrolysis, photo-
electrolysis, thermochemical generation of hydrogen, and metal-hydro
gen interactions. The importance of the last topic is emphasized.
INTRODUCTION
The term "Hydrogen Economy" has been adopted to describe the use of
hydrogen as an energy carrier. In recent years, there have been many
articles published on a possible Hydrogen Economy, both in the tech
nical literature [1] and in the popular press [2]. Therefore, a de
tailed description of a Hydrogen Economy will not be given in this
paper. However, one point, which is not always clearly presented in
some of the more popular articles, should be emphasized. Namely,
that hydrogen is not a primary source of energy, but rather it is a
convenient and environmentally desirable way of storing, transporting,
and using energy. Consequently, hydrogen must be generated from other
sources of energy such as nuclear power, solar energy, etc.
In order to determine the prospects of a Hydrogen Economy in the
future, it is necessary to become familiar with some of the problems
which must be overcome before hydrogen can be used efficiently as an
energy carrier. An indication of some of the scientific problems
and possible solutions are given in this paper. Since this is a sym
posium of physical scientists, economic or political considerations
related to a Hydrogen Economy are not discussed. The emphasis is on
materials problems which may be associated with (1) the generation of
hydrogen, (2) its utilization and (3) transmission and storage.
GENERATION OF HYDROGEN
Catalysts for Production from Coal
Although coal itself can be easily shipped and stored, the advantage
of converting coal to hydrogen would be to obtain cleaner burning
fuel. Also, hydrogen is a more convenient form of energy for some
applications such as automobile fuel.
1
2 G. G. Libowitz
One method of producing hydrogen from coal is by reaction with steam
as shown:
Coal + H20(g) -* CO, C02, H2 (1)
CO + H20(g) Ί C02 + H2 (2)
The relative amounts of the components of the synthesis gas formed in
the first reaction depend upon the type of coal used, the temperature,
and other conditions of reaction. The water shift reaction (2) re
quires catalysts in order to proceed at a sufficiently rapid rate.
However, one problem is that most heterogeneous catalysts which could
be used for this reaction tend to become poisoned by the sulfur in the
coal. With the increased use of high sulfur coals, it will be neces
sary to find new catalysts which, in addition to having good catalytic
properties, must not be poisoned by sulfur or sulfur oxides. Various
possible sulfide catalysts are being investigated including sulfo-
spinels, layered transition metal sulfides, and rare earth sulfides.
Water Electrolysis
An established method of generating hydrogen, which should become
more important with the increased availability of nuclear energy, is
the electrolysis of water. This method will also be significant in
the development of newer sources of energy such as solar, wind, and
ocean thermal gradients.
Because of problems associated with corrosion and variation in con
centration of aqueous electrolytes, the use of solid state electro
lytes are being explored. For the electrolysis of water, the mi
grating species must be either hydrogen or oxygen.
An example of a solid electrolyte, in which ionic transport is via
hydrogen, is a perfluorinated sulfonic acid polymer developed at
General Electric [3]. The behavior of this electrolyte is shown
schematically in Fig. 1. Water is introduced at the anode and is de
composed to form oxygen which is evolved, electrons which move
through the external circuit, and H ions which migrate through the
electrolyte as hydrated ions passing from one sulfonic acid group to
the next, and finally evolving as H2 gas at the cathode. Since the
sulfonic acid groups are fixed in the electrolyte, the concentration
of electrolyte remains constant. Other advantages of this electro
lyte include its ability to operate at higher pressures, the fact
that it is non-corrosive, and reduced power requirements.
Inorganic defect solids capable of ionic conduction such as yttria,
zirconia, and thoria are also being investigated as possible solid
state electrolytes. One such electrolyte system [4] (also developed
at G.E.) using calcia stabilized zirconia is illustrated in Fig. 2.
4+ 2+
Some of the Zr ions in the Zr02 lattice are substituted by Ca ,
and in order to maintain electroneutrality, oxygen vacancies VQ, are
formed in the lattice. Water, that has been vaporized by the neat of
coal oxidation (which also may be used to generate the electrical
power), is introduced at the cathode and reduced to form hydrogen gas,
while oxygen fills the lattice vacancies to form oxygen on normal
lattice sites, 0Q. At the anode, CO reacts with the lattice oxygen
to re-form the vacancies, as shown. The oxygen migrates through the
electrolyte as lattice vacancies. In addition to some of the advan
tages mentioned above for the polymer electrolyte, such cells may
