1. Think Small
20 April 2010
Nanomaterials for Green Energy
Tim Mays ( t.j.mays@bath.ac.uk )
Department of Chemical Engineering
2. A core element of energy policy
must be to ensure the provision of
sustainable, secure and safe heat
and power for everyone
3. Scope
Some examples of nanomaterials
for green energy:
• batteries
• energy efficient lighting
• hydrogen storage
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7. Li Batteries: Portable Revolution
• Energy density small & light
• Over 2 billion cells per year
• Fundamental science (1980s)
SONY cell (1991)
8. Low Carbon Transport:
HEVs & Li Batteries?
“Materials Challenge”
New or improved materials are key
to major advances:
performance, cost
9. Energy Storage: lithium battery
Charge
Li+
Discharge
Li+ - conducting
LixCoO2 cathode electrolyte Graphite anode
Hybrid
TRANSPORT
~30%+ CO2 emissions
87% cleaner
10. New or Improved Materials:
Key to major advances
“Spinel” “Layered” “Olivine”
LiMn2O4 Li(Mn,Ni)O2 LiFePO4
Structure-property relationships: atomic-scale insight
into Li transport, defects, dopants & surfaces
14. Nanoparticle Factory-on-a-Chip
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)
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:
organic
solvent water
10 nm
nanoporous alumina membranes
nanoparticles have billions of pores per cm2.
organic
L2
solvent
Large scale manufacturing of
water
L1 nanoparticles with controllable
and reproducible properties.
19. 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) +
TE
NO
Only material product of above reaction is water
Compare: hydrocarbon + oxygen → water + carbon dioxide + …
A lot of energy per unit mass of hydrogen
Compare: 40-55 MJ/kg for combustion of hydrocarbons
TE
NO
20. Basic principles of hydrogen energy systems
Ein time / location
Eout
energy produce store / energy
in hydrogen distribute out
electricity liquid hydrogen combustion
water
heat high-pressure gas fuel cell
biomass
light chemical storage
fossil fuels
radiation porous solids 2H2+O2 → 2H2O
many available many available H2 easier to store
no CO2 at
sources of sources of than many energy
point of use
energy H2 forms
25. 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