A presentation on the use of chemistry in some modern technological devices.

1. CHE-20032: SUSTAINABLE CHEMISTRY
THE CHEMISTRY BEHIND SOME MODERN
TECHNOLOGICAL APPLICATIONS
Dr Rob Jackson
Office: LJ 1.16
r.a.jackson@keele.ac.uk
http://www.facebook.com/robjteaching
http://twitter.com/robajackson, #che20032

2. Plan of session
• Timetable
• Overall aims and assessment
• Resources
• Possible applications
• Discussion of some applications
• Global sustainability issues
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3. Timetable
• Lecture: 28/03/14, 14:00-16:00 (CBA 2.017)
• Drop-in session to finalise poster titles , 04/04/14,
12:00-13:00 (CBA 1.074/5)
• Reserve: 09/05/14, 14:00-16:00 (CBA 2.017)
• Poster Session: 16/05/14, 14:00-16:00 (Multy Lab)
• Planned poster size: A1
• Poster titles/topics needed by 04/04/14
• Posters to be submitted by e-mail to me as PDF files
by 17:00 08/05/14
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4. Overall aims and assessment
• To investigate the chemistry behind some modern
technological applications.
• To consider environmental issues (mineral
resources, recycling).
• To prepare and present a poster explaining a
material or application in detail (25% of module).
• At the poster session you will answer questions
about your posters, and posters will be marked
using a scheme (to be put on the KLE).
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5. Resources
• Most information will come from the
web.
• Web links will be listed on the slides and
added to my teaching pages.
• Key links will also be put on Twitter
(#che20032).
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6. Some possible topics
(see also: http://www.bbc.co.uk/news/science-environment-
20084285)
• Li ion batteries (mobile phones, laptops etc.)
• Li air batteries
• Photovoltaic materials (used in solar power)
• Smart screen materials (OLED, plasma, LCD)
• Solid Oxide Fuel Cell (SOFC) materials
• Graphene as a silicon replacement in circuits
• Lightweight materials for vehicles
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7. Lithium ion batteries
• Lithium ion batteries are widely used in
mobile electronic devices from phones
to laptops.
• They are continually being developed
and improved; some of the latest
research is described here:
http://chemistry.st-and.ac.uk/staff/pgb/group/
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How lithium ion batteries work – (i)
• Their design is based on intercalation
compounds (compounds formed by the
reversible addition of ‘guest’ ions to a
host lattice).
• The electrolyte is a conducting
polymer such as polyacetylene:
n (H-CC-H)

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How lithium ion batteries work – (ii)
• The anode is composed of Li
embedded in graphitic carbon, forming
LixC6.
• The cathode is made from Li combined
in an intercalation compound with a
transition metal oxide like CoO2,
forming LixCoO2.

10. Lithium ion battery diagram
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11. Improvements to the lithium ion
battery
• There is much current research on
improving the performance of lithium
batteries (e.g. link on slide 7)
• These have focussed on using
nanostructured materials for the
cathode and anode.
– The rationale is that the ‘hopping distance’
for the Li+ ions is reduced.
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12. Lithium air (oxygen) batteries
(potentially higher energy density than Li ion batteries)
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The anode is either lithium
metal or a lithium containing
compound. The anode is made
of mesoporous carbon
containing a catalyst to
enhance lithium reduction from
Li+ to Li. http://chemistry.st-and.ac.uk/staff/pgb/group/lio.html
The Li+ ions combine with O2-
ions at the cathode; the
process is reversed on
charging.

13. Photovoltaic materials
• Photovoltaic materials
are used in solar power
devices, e.g. solar
panels, to produce
electric current from
sunlight.
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http://www.technologystudent.com/energy1/solar5.htm
The photovoltaic effect is the
creation of an electric current in a
material when exposed to light.

14. Organic photovoltaic materials
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http://en.wikipedia.org/wiki/Organic_solar_cell#Organic_photovoltaic_materials
Some organic photovoltaic materials
A single layer photocell

15. Smart screen materials
• Smart screen technology is
developing fast.
• The latest, including the
curved screens being
marketed by Samsung, use
OLEDs (organic light-
emitting diodes).
• Other materials used include
‘plasmas’ and liquid crystals.
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A curved OLED screen

16. OLED screens
• OLEDs* work on the
principle that certain
organic molecules emit
light when an electric
current is passed
through them. No
backlight is required.
• An example of a
molecule used in
OLED devices is
Al(C9H6NO)3, which
is often abbreviated
to Alq3
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*PLEDs work on the same
principle with polymers.

17. Solid oxide fuel cells (SOFCs)
• Fuel cells convert the
chemical energy from a fuel
into electricity via a chemical
reaction (usually oxidation).
• Solid oxide fuel cells have
solid oxide electrolytes, e.g.
Y2O3 stabilised ZrO2.
• Cathode and anode
materials have particular
properties as well.
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In this example, the fuel is H2,
which is oxidised by the
incoming O2- ions, releasing
electrons.
http://en.wikipedia.org/wiki/Solid_oxide_fuel_cell

18. Solid oxide fuel cell materials
• Research is being done to improve the
performance of SOFCs
– This includes improving the materials used
to reduce the running temperature.
– Also proton-conducting SOFCs are being
developed, where protons are transported
through the electrolyte instead of O2- ions,
which also reduces the running
temperature.
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19. Graphene as a silicon replacement
in circuits
See: http://www.bbc.co.uk/news/science-environment-25944824
• Graphene is being investigated as an
alternative to silicon in integrated circuits:
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• The paper describes how
the problems with using
graphene in circuit design
has been overcome

20. Lightweight materials for vehicles
http://www.boeing.com/commercial/aeromagazine/articles/qtr_4_06
/article_04_2.html
• This is a slightly less ‘chemical’ topic, but
composite materials are increasingly being
used in vehicle construction.
– For example, the Boeing 787 Dreamliner only has
10% steel, and the rest of it is constructed from:
15% Ti, 20% Al and 50% composite materials.
– (More research needed to identify ‘composite
materials’!)
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21. Rare earth (RE) elements and
resource issues
• The ‘rare earth’ elements
are widely used in modern
technological devices.
They are more often called
lanthanides now.
• They are not all ‘rare’; Ce
is the 25th most common
element on the planet!
• However there are supply
problems with some.
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22. The varied colours of the RE
nitrates
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http://www.bbc.co.uk/news/magazine-26687605
Pm (promethium) is missing as it doesn’t occur naturally

23. Some applications of the RE
elements
• Neodymium is magnetic (10 times as powerful as
iron magnets): used in computer hard drives and
miniature speakers.
• Dysprosium is used in control rods in nuclear
reactors
• Erbium is for sending signals along optical fibres – it
produces light in the near IR.
• Europium is used for anti-counterfeiting in Euro
notes (the blue-pink stars on the €20 note contain
Eu!).
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24. Resourcing issues with RE
elements
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More than 85% of
the world's supply of
rare-earth metals
comes from China,
including almost
100% of the ‘heavy’
ones. In 2010 China
started controlling
output, with a
dramatic effect on
prices.