T Mays Presentation - Think Small Event
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Think Small 20 April 2010 Nanomaterials for Green Energy Tim Mays ( [email protected] ) Department of Chemical Engineering
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BEN Event - 20/04/10 - Think Small, NSQI Building, University of Bristol.
Transcript of T Mays Presentation - Think Small Event
Think Small20 April 2010
Nanomaterials for Green Energy
Tim Mays ( [email protected] )Department of Chemical Engineering
A core element of energy policy
must be to ensure the provision of
sustainable, secure and safe heat
and power for everyone
Scope
Some examples of nanomaterialsfor green energy:
• batteries• energy efficient lighting• hydrogen storage
Li Batteries: Portable Revolution
• Energy density ���� small & light
• Over 2 billion cells per year
• Fundamental science (1980s)
���� SONY cell (1991)
Low Carbon Transport:
HEVs & Li Batteries?
“Materials Challenge”
New or improved materials are key
to major advances:
performance, cost
Discharge
Charge
Li+
LixCoO2 cathode Graphite anodeLi+ - conductingelectrolyte
Energy Storage: lithium battery
Hybrid
87% cleaner
TRANSPORTTRANSPORT~30%+ CO~30%+ CO22 emissionsemissions
“Layered”Li(Mn,Ni)O2
“Olivine”
LiFePO4
“Spinel”LiMn2O4
New or Improved Materials: Key to major advances
Structure-property relationships: atomic-scale insight
into Li transport, defects, dopants & surfaces
New LiFePO4 Cathode
Scale-up
Blue: PO4
Yellow: FeO6
� Defect chem?
� Li+ transport ?
� Doping: Zr,Nb?
LiFePO4: Li Diffusion Path?
LiPO4 tetrahedraFeO6 octahedra
[010]
[100]
� [010] channel (0.55eV) & curved path
Chem. Mater (2005)
M Saiful IslamDepartment of Chemistry
Vision: ‘Large scale production of nanoparticles with controllable and reproducible characteristics will lead to a radical shift in all manufacturing sectors …’ (RAEng/Royal Soc., 2004)
Nanoparticle Factory-on-a-Chip
Large scale manufacturing of nanoparticles with controllableand reproducible properties.
L1
L2
Methodology: Forcing water through a nanoporous membrane into an immiscible solvent produces nanodroplets, which are then converted into nanoparticles, with control over particle shape, size and properties:
water
organic solvent
10 nm
waterorganic solvent
nanoparticlesnanoporous alumina membranes have billions of pores per cm2.
Lighting fixtures based on quantum dot nanoparticles are 20-30 % more efficient that fluorescent bulbs and do not contain harmful chemicals. Prototype quantum dot-based displays are already more efficient than conventional LCD displays.
Today they are made in batches of a few milligrams at a time, against projected market demand of three tonnes per year by 2012! (The Economist, 04/03/2010; data from Coe-Sullivan, Nature Photonics, 3, 315-316, 2009 )
©B
enoit Dubertret, 2004
Nanoparticles are currently used in many applications (fuel cells, sun-blocking creams, solar panels, fuel additives…) but transformative developments are hindered by the lack of methods to produce large quantities of nanoparticles with controllable and reproducible properties.
One example of what will be possible to achieve with better nanoparticle property control:
Diameter (nm)
Davide MattiaDepartment of Chemical Engineering
Hydrogen energy
hydrogen + oxygen → water + energy
2H2 + O2 → 2H2O
energy = 120 - 142 MJ/kg heat (combustion)
= 1.23 V electrical potential + 24 MJ/kg heat (fuel cell) +
Only material product of above reaction is waterCompare: hydrocarbon + oxygen → water + carbon dioxide + …
A lot of energy per unit mass of hydrogenCompare: 40-55 MJ/kg for combustion of hydrocarbons
NOTE
NOTE
Basic principles of hydrogen energy systems
energyin
producehydrogen
store /distribute
energyout
electricityheatlight
radiation
waterbiomass
fossil fuels
liquid hydrogenhigh-pressure gaschemical storage
porous solids
combustionfuel cell
2H2+O2→2H2O
no CO2 atpoint of use
H2 easier to storethan many energy
forms
many available sources of
H2
many available sources of
energy
energyin
producehydrogen
store /distribute
energyout
electricityheatlight
radiation
waterbiomass
fossil fuels
liquid hydrogenhigh-pressure gaschemical storage
porous solids
combustionfuel cell
2H2+O2→2H2O
no CO2 atpoint of use
H2 easier to storethan many energy
forms
many available sources of
H2
many available sources of
energy
time / locationEin Eout
Hydrogen storage
technologies
Familiar nanoporous materials
Mays, Stud Surf Sci Catal160 (2006) 57
Nanopores
A core element of energy policy
must be to ensure the provision of
sustainable, secure and safe heat
and power for everyone
Nanomaterials will have an
important role in future low
carbon energy technologies
