Lithium-Ion Battery Nano-technology

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Lithium-Ion Battery Nano-technology
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• An Overview of the battery technology that powers
  our mobile society.

Bryan Lamble Energy Law, Spring 2008
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Battery History and Basics

• The modern battery was developed by Italian
  physicist Alessandro Volta in 1800.
• Ingredients Zinc, Saltwater paper, and Silver
• An electrochemical reaction.
• The Voltaic Pile

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The Voltaic Pile
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Battery Chemistry 101

• Electrochemical reaction - a chemical reaction
  between elements which creates electrons.
• Oxidation occurs on the metals (electrodes),
  which creates the electrons.
• Electrons are transferred down the pile via the
  saltwater paper (the electrolyte).
• A charge is introduced at one pole, which builds
  as it moves down the pile.

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Primary vs. Secondary Batteries

• Primary batteries are disposable because their
  electrochemical reaction cannot be reversed.
• Secondary batteries are rechargeable, because
  their electrochemical reaction can be reversed by
  applying a certain voltage to the battery in the
  opposite direction of the discharge.

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Standard Modern Batteries

• Zinc-Carbon used in all inexpensive AA, C and D
  dry-cell batteries. The electrodes are zinc and
  carbon, with an acidic paste between them that
  serves as the electrolyte. (disposable)
• Alkaline used in common Duracell and Energizer
  batteries, the electrodes are zinc and
  manganese-oxide, with an alkaline electrolyte.
  (disposable)
• Lead-Acid used in cars, the electrodes are lead
  and lead-oxide, with an acidic electrolyte.
  (rechargeable)

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Battery types (contd)

• Nickel-cadmium (NiCd)
• rechargeable,
• memory effect
• Nickel-metal hydride (NiMH)
• rechargeable
• no memory effect
• Lithium-Ion (Li-Ion)
• rechargeable
• no memory effect

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Recharge-ability the memory effect

• Recharge-ability basically, when the direction
  of electron discharge (negative to positive) is
  reversed, restoring power.
• the Memory Effect (generally) When a battery is
  repeatedly recharged before it has discharged
  more than half of its power, it will forget its
  original power capacity.
• Cadmium crystals are the culprit! (NiCd)

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Lithium

• Periodic Table Symbol Li
• Atomic Weight 3 (light!)
• Like sodium and potassium, an alkali metal.
  (Group 1 s 1 through 7)
• Highly reactive, with a high energy density.
• Used to treat manic-depression because it is
  particularly effective at calming a person in a
  manic state.

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The Periodic Table
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Lithium (Ion) Battery Development

• In the 1970s, Lithium metal was used but its
  instability rendered it unsafe and impractical.
  Lithium-cobalt oxide and graphite are now used as
  the lithium-Ion-moving electrodes.
• The Lithium-Ion battery has a slightly lower
  energy density than Lithium metal, but is much
  safer. Introduced by Sony in 1991.

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Advantages of Using Li-Ion Batteries

• POWER High energy density means greater power
  in a smaller package.
• 160 greater than NiMH
• 220 greater than NiCd
• HIGHER VOLTAGE a strong current allows it to
  power complex mechanical devices.
• LONG SHELF-LIFE only 5 discharge loss per
  month.
• 10 for NiMH, 20 for NiCd

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Disadvantages of Li-Ion

• EXPENSIVE -- 40 more than NiCd.
• DELICATE -- battery temp must be monitored from
  within (which raises the price), and sealed
  particularly well.
• REGULATIONS -- when shipping Li-Ion batteries in
  bulk (which also raises the price).
• Class 9 miscellaneous hazardous material
• UN Manual of Tests and Criteria (III, 38.3)

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Environmental Impact of Li-Ion Batteries

• Rechargeable batteries are often recyclable.
• Oxidized Lithium is non-toxic, and can be
  extracted from the battery, neutralized, and used
  as feedstock for new Li-Ion batteries.

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The Intersection

• In terms of weight and size, batteries have
  become one of the limiting factors in the
  development of electronic devices.
• http//www.nanowerk.com/spotlight/spotid5210.php
• The problem with...lithium batteries is that
  none of the existing electrode materials alone
  can deliver all the required performance
  characteristics including high capacity, higher
  operating voltage, and long cycle life.
  Consequently, researchers are trying to optimize
  available electrode materials by designing new
  composite structures on the nanoscale.

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Nano-Science and-Technology

• The attempt to manufacture and control objects at
  the atomic and molecular level (i.e. 100
  nanometers or smaller).
• 1 nanometer 1 billionth of a meter (10-9)
• 1 nanometer 1 meter 1 marble Earth
• 1 sheet of paper 100,000 nanometers

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Nano S T (contd)

• Nano-science research of the differing
  behavioral properties of elements on the nano
  scale.
• Conductivity (electric/thermal), strength,
  magnetism, reflectivity.... Sometimes these
  properties differ on the nanoscale.
• Carbon is particularly strong on the nano scale.
• C60 Fullerene, a.k.a buckyball

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Nano S T (contd)

• Nano-technology the use of nanoscale materials
  in critical dimensions of mechanical devices.
• Nanotubes -- carbon molecules have greater
  mechanical strength at less weight per volume.
• Nanotransistors -- the computer industrys best
  technology features microchips with transistors
  as small as 45nm.
• Batteries with nanoscale materials deliver more
  power quickly with less heat.

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Environmental Impacts and Use of Nanotechnology

• Smaller scale technology means less resources
  used and less waste.
• The EPA recently issued research grants to use
  nanotechnology to develop new methods of
  detecting toxins in water.

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An example of the intersection...

• From graphite to metallic tin (electrodes), but
  metallic tin isnt great eitheryet.
• ...the biggest challenge for employing metallic
  tin...is that it suffers from huge volume
  variation during the lithium insertion/extraction
  cycle, which leads to pulverization of the
  electrode and very rapid capacity decay."
• But nanotechnology could offer a solution...

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• The Director of the Institute of Chemistry at the
  Chinese Academy of Sciences published a paper in
  February describing the novel carbon
  nanocomposite above as a promising electrode
  material for lithium-ion batteries.

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Another example...

• The storage capacity of a Li-Ion battery is
  limited by how much lithium can be held in the
  battery's anode, which is typically made of
  carbon. Silicon has a much higher capacity than
  carbon, but also has a drawback.
• Silicon placed in a battery swells as it absorbs
  positively charged lithium atoms during charging,
  then shrinks during use as the lithium ion is
  drawn out of the silicon. This cycle typically
  causes the silicon to pulverize, degrading the
  performance of the battery.

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The Nano-technology solution...

• The lithium is stored in a forest of tiny
  silicon nanowires, each with a diameter one
  one-thousandth the thickness of a sheet of paper.
  The nanowires inflate to four times their normal
  size as they soak up lithium but, unlike other
  silicon shapes, they do not fracture.
• See next slide

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• Photos taken by a scanning electron microscope of
  silicon nanowires before (left) and after (right)
  absorbing lithium. Both photos were taken at the
  same magnification. The work is described in
  High-performance lithium battery anodes using
  silicon nanowires, published online Dec. 16 in
  Nature Nanotechnology.

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The Potential of Li-Ion Batteries

• Electrodes that dont deteriorate
• metallic tin with carbon hollow spheres
• silicon nanowires
• 2D 3D battery design
• Forested rods on a thin film electrode
• Stacked rods in a truck bed

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Nano Li-Ion ?

• Nanotechnology and Li-Ion applications in the
  commercial sector are apparent...
• lighter, more powerful batteries increase user
  mobility and equipment life.
• DeWalt 36volt cordless power tools
• Nanotechnology Li-Ion applications in the
  residential sector are not so obvious...
• HVAC system batteries? Micro-generated energy
  storage?

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Micro-Generated Energy Storage

• Li-Ion batteries high energy density allows
  batteries them to power complex machinery.
• Li-Ion batteries recharge quickly and hold their
  charge longer, which provides flexibility to the
  micro-generator.
• particularly helpful for wind and solar
  generators!
• Lightness, and power per volume allow for storage
  and design flexibility.

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Finally, an interesting idea...

• Background
• battery research results in annual capacity gains
  of approximately 6
• Moores Law The number of transistors on a
  computer microchip will double every two years.
  (40 years of proof!)
• Idea If battery technology had developed at the
  same rate, a heavy duty car battery would be the
  size of a penny.

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Links to References

• http//electronics.howstuffworks.com/battery.htm
• http//everything2.com/e2node/Lithium2520ion2520
  battery
• http//www.batteryuniversity.com
• http//news-service.stanford.edu/news/2008/january
  9/nanowire-010908.html
• http//www.nano.gov/html/research/industry.html
• http//en.wikipedia.org/wiki/Buckminster_Fuller
• http//www.nanowerk.com/spotlight/spotid5210.php