clean energy materials: crystal gazing on the atomic scale · crystal gazing understanding of...
TRANSCRIPT
SaifulIslamSize MattersMay 30, 2004 1
Clean Energy Materials:Crystal Gazing on the Atomic Scale
Saiful Islam Inaugural Lecture, 25 April 2007
SaifulIslamBath
April 2007 2
Alice in Wonderland
Lewis Carroll
“Begin at the beginning. Go on until the end.
Then stop”.
SaifulIslamBath
April 2007 3
2. Crystal Gazing
3. Fuel Cells 4. Lithium Batteries
1. Clean Energy
Menu
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April 2007 4
Clean Energy
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April 2007 5
Energy Challenge
•Global warming
“Hot topic”
•Energy demand
•Fossils fuels: CO2
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April 2007 6
Cleaner sustainable
alternatives?...
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April 2007 7
Power to the People!
Diverse energy mix
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April 2007 8
…Untapped?
Roman Baths…Thermal Energy
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April 2007 9
Hybrid electric cars?
Fuel Cells
Local heat & power?
SOFC Space heater
Lithium Batteries
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April 2007 10
Fuel Cells Lithium Batteries
“Chemical Solutions”
New crystalline materials are key
to major advances
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April 2007 11
Low Carbon Future?Low Carbon Future?Low Carbon Future?Low Carbon Future?
Oil reserves?
“The Stone Age did not end
because of the lack of stone”
Zaki Yamani (Saudi oil minister,1970s)
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April 2007 12
Crystal Gazing
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April 2007 13
Crystalline Solids
Salt:
sodium chloride
sodium ion chlorine ion
Atomic symmetry
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April 2007 14
Size is Important: “Nano”
1 nanometre = 0.000000001 metre
1 millionth thickness of a human hair
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April 2007 15
“Defects” in Solids
“Solids are like people -
imperfect!
It’s the defects that make
them unique & interesting”
(J. Corish)
S.Dali“Galatea of the Spheres”
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April 2007 16
Photography: Silver Defects
Postdoc: New York(1988-90)
Vacancy Interstitial
Silver chloride: AgCl
SaifulIslamSize MattersMay 30, 2004 17
Defects in silver chloride: AgCl
silver ion interstitial
silver ion vacancy
Experiment? Search for needles in a crystalline haystack
Pointer
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April 2007 18
Impurity or Dopant: Dirty Crystals!
“To what…shall I compare thyne eyne?
Crystal is muddy”
[Demetrius to Helen: Midsummer Nights Dream]
W. Shakespeare (born 23 April 1564, died 23 April 1616)
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April 2007 19
Computer Modelling
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April 2007 20
Not all chemists
wear white coats
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• Forces: nature’s glue
• Mathematical model
• Number-crunching
Computer Modelling?
NaCl
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April 2007 22
Crystal Structures
ApatitePerovskite
Start? Model experimental structures to within 1%
E. Kendrick
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April 2007 23
Structure Modelling
Now
Nobel Prize
1962
DNA: Crick & Watson 1953
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April 2007 24
Atomic-Scale Gazing
crystal
structure
ion
conduction
dopant vacancy
surface
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April 2007 25
Modelling Aims
Understanding, Insight &
Prediction
Fundamental Science
Underpins Technology
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April 2007 26
Scientific Marriage
Computational
Chemistry
Synthesis &
Experiments
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April 2007 27
Fuel Cell Materials
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April 2007 28
“Godfather” of Ion Conductors
Michael Faraday (Royal Institution, London)
1835 “…that materials when sought forwould conduct electricity in the solid state”
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April 2007 29
What is a solid oxide fuel cell?...
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April 2007 30
Electrochemical Sandwich
Fuel Oxidant (Air)
Electrode ElectrodeIon conductor
e- e-
O2
O2-
H2
H2O
(solid oxide)
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April 2007 31
Fuel cell animation...
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April 2007 32
Solid Oxide Polymer
Fuel Cell Types
Problem: high temp
Solid oxide fuel cell
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April 2007 33
Novel Perovskite Oxides
• Lanthanum gallate
LaGaO3
• Discovery: oxide-ion
conductor
• Path of moving ions? oxide ions (red)
J. Irvine; J. Kilner
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April 2007 34
Bath Centre
Bathwick Hill
University of Bath
Energy Landscape
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April 2007 35
Oxide ion conduction
Oxide ion vacancy
•What is the path?
LaGaO3
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April 2007 36
Range of perovskites since 1995 Yashima (2003)
“Curved” conduction path
LaGaO3
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April 2007 37
Apatite for Fuel Cells
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April 2007 38
Apatites: From Nature to Technology
• “Bio-inspired”
• Hydroxy-apatite: bones
& teeth
• New synthetic apatite-
silicates
N. De Leeuw
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April 2007 39
Crystal World: Silicates
Silicon-oxygentetrahedra (4-sided)
Silica: sand & quartz Apatite-silicates
SaifulIslamSize MattersMay 30, 2004 40
Novel Apatite Silicate
silicon-oxygen
tetrahedron
oxygen ion channel
Next…bio-inspiredA. Jones
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Also bio-inspired!
Wake-up call?
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April 2007 42
• Exciting discovery
• New family of oxide-ion conductor (P. Slater)
• Defects? How do they move?
Apatites: Why Interest ?
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April 2007 43
Ion Conduction Path?
• Tale of the unexpected!
• “Snake-like”path
• Future: Boron oxynitride
(BON)
���� “Bon apatite”
oxygen defect
silicon-oxygen
tetrahedra
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April 2007 44
Apatite animation...
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April 2007 45
Lithium Battery Materials
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April 2007 46
Size Matters: Size Matters: Size Matters: Size Matters: Portable Revolution
• Energy density ���� small & light
• Fundamental chemistry (1980s)
���� SONY cell (1991)
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April 2007 47
DischargeCharge
LixCoO2 cathode Graphite anodeLi+-conductingelectrolyte
Charge of the Battery Brigade
SaifulIslamSize MattersMay 30, 2004 48
Current cathode material
Lithium ions
cobalt
oxide sheets
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April 2007 49
•Transport ���� 30% CO2 emissions
•Hybrid electric cars: petrol + battery
Next Generation ?
EPSRC Supergen:
Energy Storage Materials
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April 2007 50
New Battery Material
•Non-toxic
•Cheaper
•Scale-up
Lithium iron phosphate: LiFePO4
2006
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April 2007 51
Crystal Shapes
• Solid surfaces and morphology
S.Parker; D. Sayle
Crystals at
home
(x 1000)
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April 2007 52
Fuel cell: LaCoO3Li battery: LiFePO4
Small But Perfectly Formed
Modelling
Microscopy
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April 2007 53
Doping Battery Materials
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April 2007 54
Not this type!
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April 2007 55
Doping in Solids
� Dopant ions
� Performance enhancing!
Which dopants go in?
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April 2007 56
Goodenough,
(Texas) et al
Zr, Nb doping
���� NO
Chiang (MIT,
USA) et al
Zr, Nb doping
���� YES
Doping Controversy!
Atomic-Scale Modelling - shed some light?
Lithium battery: Phosphate LiFePO4
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April 2007 57
LiFePO4: Modelling Dopants
Mn2+ Zr4+ Nb5+
Energy
Likely
doping...
Unlikely
doping...
1
2
3
4
5
6
7
8
9
-1
0
Computer says “no”!
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April 2007 58
And so the story ends
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April 2007 59
Modelling of Crystalline
Materials on the Atomic Scale
Crystal Gazing
Understanding of Properties for
Clean Energy Applications
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April 2007 60
Computational Chemistry
“The most important applications of these methods are to reveal the
contrasting states of order and
disorder, but above all the intricacy
and beauty of matter at the atomic
level”
Richard Catlow FRSUCL & The Royal Institution
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April 2007 61
Lithium Batteries
Chemistry is key to exciting
breakthroughs
Future Energy Mix?
Fuel Cells
SOFC Space heater
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April 2007 62
Thanks to…
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April 2007 63
Collaborators
Calabria, Italy, 1985
“Defects in Solids”
Me
T. Norby
A. Chadwick
R. Catlow
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April 2007 64
The molecular revolution
in sustainable energy
Exhibitionists Unite!
•Matt Davidson & Laurie Peter
•Royal Society & Buckingham Palace (2006)
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April 2007 65
Final Thanks
For tolerating my defects!
Gita, Yasmin & Zak
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April 2007 66
End quote: Darwin Exhibition
“The real voyage of discovery consists
not only in seeking new landscapes,
but in having new eyes”
Marcel Proust (1871 - 1922)