Table Of ContentNanomaterials for Solid State Hydrogen Storage
Fuel Cells and Hydrogen Energy
Series Editor: Narottam P. Bansal
NASA Glenn Research Center
Cleveland, OH 44135
[email protected]
Aims and Scope of the Series
During the last couple of decades, notable developments have taken place in the
science and technology of fuel cells and hydrogen energy. Most of the knowledge
developed in this field is contained in individual journal articles, conference pro-
ceedings, research reports, etc. Our goal in developing this series is to organize this
information and make it easily available to scientists, engineers, technologists,
designers, technical managers and graduate students. The book series is focused to
ensure that those who are interested in this subject can find the information quickly
and easily without having to search through the whole literature. The series includes
all aspects of the materials, science, engineering, manufacturing, modeling, and
applications. Fuel reforming and processing; sensors for hydrogen, hydrocarbons
and other gases will also be covered within the scope of this series. A number of
volumes edited/authored by internationally respected researchers from various
countries are planned for publication during the next few years.
Titles in this series
Nanomaterials for Solid State Hydrogen Storage
R.A. Varin, T. Czujko, and Z. S. Wronski
ISBN 978-0-387-77711-5, 2009
Modeling Solid Oxide Fuel Cells: Methods, Procedures and Techniques
R. Bove and S. Ubertini, eds.
ISBN 978-1-4020-6994-9, 2008
Robert A.Varin (cid:129) Tomasz Czujko
Zbigniew S. Wronski
Nanomaterials for Solid
State Hydrogen Storage
Robert A. Varin Tomasz Czujko
University of Waterloo University of Waterloo
Department of Mechanical Department of Mechanical
and Mechatronics Engineering and Mechatronics Engineering
200 University Ave. W 200 University Ave. W
Waterloo, Ontario Waterloo, Ontario
Canada N2L 3G1 Canada N2L 3G1
Zbigniew S. Wronski
CANMET Energy Technology Centre
Hydrogen Fuel Cells and
Transportation Energy
Natural Resources Canada
1 Haanel Drive
Ottawa, Ontario
Canada K1A 1M1
ISBN: 978-0-387-77711-5 e-ISBN: 978-0-387-77712-2
DOI: 10.1007/978-0-387-77712-2
Library of Congress Control Number: 2008929618
© Springer Science+Business Media, LLC 2009
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Preface
Although hydrogen as a chemical element has been known to the humankind and
used in various capacities for a very long time, only in the past 15 years its importance
to the world population as an energy vector has gradually emerged. A long-term
reliance of humanity on the energy derived solely from fossil fuels, such as coal in
the nineteenth and crude oil and natural gas in the twentieth century, has led to a
number of new challenges facing all of us in the twenty-first century, such as sharp
reduction in the world crude oil and eventually coal supply, global warming and
following climate changes due to the release of growing amounts of greenhouse gas
CO, and poor urban air quality. Hydrogen is essentially the only viable remedy for
2
the growing world energy problems. Hydrogen is a very attractive alternative
energy vector for replacing fossil fuel-based economy. The future Hydrogen
Economy offers a potential solution to satisfying the global energy requirements
while reducing (and eventually eliminating) carbon dioxide and other greenhouse
gas emissions and improving energy security. Hydrogen is ubiquitous, clean,
efficient, and can be produced directly from sunlight and water by biological organ-
isms and using semiconductor-based systems similar to photovoltaics. Hydrogen
can also be produced indirectly via thermal processing of biomass or fossil fuels
where the development of advanced technological processes combined with a CO
2
sequestration is emerging.
However, this rosy picture, as it usually happens in a real life, is marred by a
number of obstacles which must be overcome before the Hydrogen Economy
becomes a reality. One of these obstacles is safe and efficient storage of hydrogen
particularly for mobile/automotive applications where hydrogen gas will be
supplied to fuel cells that, in turn, will power the transport vehicles in a clean,
inexpensive, safe, and efficient manner. From all possible solutions to hydrogen
storage the one which relies upon storage in solid media (hydrides) is the most
attractive one. The fast emerging nanoscience/nanotechnology will allow fabricating
nanomaterials for solid-state hydrogen storage that can, in a long run, revolutionize
hydrogen storage.
This book is our modest contribution to this innovative area of hydrogen storage.
Wherever possible we tried to illustrate the hydrogen storage behavior by our own
results. In Chap. 1, we introduce the reader to the motivation for the transformation
to the Hydrogen Economy. In a number of following sections/subsections, we
v
vi Preface
provide a comprehensive synchronic history of development of hydrides and nano-
materials including the existing fabrication methods with a special emphasis on ball
(mechanical) milling in high-energy mills. Important hydride properties and experi-
mental techniques for assessing hydrogen storage behavior are also discussed. In
Chap. 2, we review hydrogen storage properties of selected simple metal and inter-
metallic hydrides with the most emphasis on magnesium hydride (MgH) which
2
now can be treated as a model hydride whose hydrogen storage properties in nanos-
tructured form can be used as a benchmark for comparing the properties of other
hydrides. Chapter 3 brings a thorough review of the properties of complex hydrides
whose high volumetric and gravimetric capacities make them most attractive for the
vehicular solid-state hydrogen storage in transportation. Chapter 4 provides infor-
mation on carbons and nanocarbons as alternative means of hydrogen storage to
solid hydrides. This includes diamond and nanodiamond, graphene, ordered graph-
ites and nanographites, disordered and active carbons, fullerenes, carbon nano-
tubes, and other nanoshapes. Chapter 5 is a sort of an executive summary where we
provide a critical assessment of the present state of knowledge and make predic-
tions for the future developments.
Waterloo, ON Robert A. Varin
Waterloo, ON Tomasz Czujko
Ottawa, ON Zbigniew S. Wronski
Contents
1 Introduction .............................................................................................. 1
1.1 Motivation: The Hydrogen Economy ................................................ 1
1.2 Brief, Synchronic History of Development
of Hydrides and Nanomaterials ......................................................... 7
1.2.1 Early Investigations of Metal–Hydrogen Systems
and Hydrides .......................................................................... 7
1.2.2 Early Routes to Nanomaterials .............................................. 10
1.2.3 Historical Development of Classical Hydrogen
Storage AB Alloys ................................................................ 13
5
1.2.4 Historical Development of Interstitial Hydrides
in Other Intermetallic Systems .............................................. 15
1.2.5 Historical Development of Nanophase AB
2
Intermetallic Hydrides ........................................................... 16
1.2.6 New Routes to Nanomaterials: Mechanical Alloying
and Mechanochemical Activation ......................................... 17
1.2.7 Historical Development of Lightweight Metal Hydrides
and Hydride Complexes ........................................................ 18
1.2.8 Early Studies of Noninterstitial Transition Metal
Ternary Hydrides ................................................................... 20
1.2.9 Toward Chemical/Complex Hydrides ................................... 21
1.2.10 Historical Development of Nanocarbons
and Carbon Nanotubes .......................................................... 23
1.2.11 New Materials and Techniques .............................................. 25
1.3 Nanoprocessing in Solid State in High-Energy Ball Mills ................ 27
1.3.1 Processes for the Synthesis of Nanostructured
Materials ................................................................................ 27
1.3.2 Milling Processes and Equipment ......................................... 28
1.3.3 Nanoprocessing Methods and Mechanisms .......................... 37
1.3.3.1 Mechanical Milling ................................................ 38
1.3.3.2 Mechanical Alloying .............................................. 39
vii
viii Contents
1.3.3.3 Mechanochemical Activation ................................. 40
1.3.3.4 Mechanochemical Synthesis
(Mechanosynthesis) of Nanohydrides .................... 52
1.3.3.5 Mechanical Amorphization .................................... 55
1.4 Important Hydride Properties and Experimental Techniques ........... 56
1.4.1 Thermodynamics ................................................................... 56
1.4.1.1 Pressure–Composition–Temperature
(PCT) Properties ..................................................... 56
1.4.1.2 Calculation of Activation Energy ........................... 60
1.4.2 PCT and Kinetic Curves Determination by Volumetric
Method in a Sieverts-Type Apparatus ................................... 65
1.4.3 Microstructural Characterization of Ball-Milled
Hydrides ................................................................................ 71
1.4.4 Weight Percent of a Hydride Phase and Hydrogen
by DSC Method ..................................................................... 73
References .................................................................................................. 74
2 Simple Metal and Intermetallic Hydrides ............................................. 83
2.1 Mg/MgH ........................................................................................... 83
2
2.1.1 Crystallographic and Material Characteristics ...................... 83
2.1.2 Hydrogen Storage Characteristics
of Commercial Mg and MgH ............................................... 87
2
2.1.2.1 Absorption .............................................................. 87
2.1.2.2 Desorption .............................................................. 93
2.1.3 Hydrogen Storage Characteristics of Mechanically
(Ball) Milled MgH................................................................ 102
2
2.1.3.1 Microstructural Evolution During Milling and
Subsequent Cycling of Commercial MgH
2
Powders .................................................................. 103
2.1.3.2 Hydrogen Absorption of Ball-milled
Commercial MgH Powders ................................... 112
2
2.1.3.3 Hydrogen Desorption of Ball-milled
Commercial MgH Powders ................................... 115
2
2.1.4 Hydrogen Storage Characteristics of MgH Synthesized
2
by Reactive Mechanical (Ball) Milling of Mg ...................... 129
2.1.5 Aging Effects in Stored MgH Powders ................................ 146
2
2.1.6 Other Methods of Synthesis of Nanostructured
MgH than Ball Milling ......................................................... 147
2
2.2 MgH with Catalytic Additives ......................................................... 151
2
2.2.1 Mg/MgH–Metals and Intermetallics .................................... 152
2
2.2.1.1 Desorption in Vacuum ................................................. 152
2.2.1.2 Desorption at Atmospheric Pressure of Hydrogen ..... 153
2.2.2 Mg/MgH–Metal Oxides ....................................................... 165
2
2.2.3 Mg/MgH–Carbon / Graphite and Carbon Nanotubes ........... 169
2
Contents ix
2.3 Other Metal Hydrides Containing Mg............................................... 170
2.4 AlH ................................................................................................... 174
3
2.5 Other Metal and Intermetallic-based Hydrides:
New Developments ........................................................................... 177
2.5.1 Metal Hydrides ...................................................................... 179
2.5.2 Rare-Earth AB Compounds.................................................. 181
5
2.5.3 Titanium–Iron AB Compounds ............................................. 182
2.5.4 Titanium and Zirconium AB Compounds ............................ 183
2
2.5.5 Other Novel Intermetallic Hydrides ...................................... 183
References .................................................................................................. 183
3 Complex Hydrides ................................................................................... 195
3.1 Ternary Transition Metal Complex Hydrides ................................... 196
3.1.1 MgNiH ................................................................................ 196
2 4
3.1.2 MgFeH ................................................................................ 198
2 6
3.1.3 MgCoH ................................................................................ 204
2 5
3.2 Alanates ............................................................................................. 206
3.2.1 NaAlH .................................................................................. 206
4
3.2.2 LiAlH.................................................................................... 213
4
3.2.3 Mg(AlH) and Ca(AlH) ...................................................... 223
4 2 4 2
3.3 Amides .............................................................................................. 231
3.4 Metal Borohydrides ........................................................................... 240
3.5 Destabilization of High Desorption Temperature
Hydrides by (Nano)Compositing ...................................................... 253
3.5.1 MgH–LiAlH Composite System ......................................... 255
2 4
3.5.2 MgH–NaAlH Composite System ........................................ 265
2 4
3.5.3 MgH–NaBH Composite System ......................................... 270
2 4
References .................................................................................................. 281
4 Carbons and Nanocarbons ...................................................................... 291
4.1 Diamond and Nanodiamonds ............................................................ 291
4.2 Graphene, Ordered Graphite, and Nanographites ............................. 294
4.2.1 Graphene ................................................................................ 294
4.2.1.1 In-Plane σ and Out-of-Plane π Bonding ................. 295
4.2.1.2 Van der Walls Interplanar and Intermolecular
Interactions ............................................................ 296
4.2.1.3 Physisorption of Hydrogen on Carbons ................. 297
4.2.1.4 Chemisorption of Hydrogen on Carbons ................ 298
4.2.2 Graphitic Nanofibers, Whiskers, and Polyhedral Crystals .... 299
4.2.3 Graphite ................................................................................. 299
4.3 Disordered and Active Carbons ......................................................... 301
4.3.1 Disordered Graphites and Mechanically-Activated
Carbons .................................................................................. 301
x Contents
4.3.2 Active Carbons and Chemically Activated Carbons ............. 303
4.3.3 Amorphous Carbon ............................................................... 304
4.4 Highly Ordered Fullerenes, Carbon Nanotubes,
and Carbon Nanohorns ...................................................................... 305
4.4.1 Fullerenes and Hydrofullerenes ............................................. 305
4.4.2 Carbon Nanotubes ................................................................. 308
4.4.3 Carbon Nanohorns ................................................................. 312
4.4.4 Nanostructured Carbon Shells and Carbon Onions ............... 314
References .................................................................................................. 317
5 Summary ................................................................................................... 321
5.1 Metal/Intermetallic Hydrides ............................................................ 322
5.2 Complex Hydrides ............................................................................. 323
5.3 Nanocarbons and Others ................................................................... 324
Index ................................................................................................................ 327
