NANOTECHNOLOGY IN ENERGY

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• NANOTECHNOLOGY IN ENERGY
• Draft RoadMaps on
• Solar Cells
• Thermoelectricity
• Battaries and Supercapacitors
• Heat Insulation/Conductance
• Ottilia Saxl
• THE INSTITUTE OF NANOTECHNOLOGY, UK
• Jitka Kubatova
• TECHNOLOGY CENTRE AS CR, CR
• __________________________________________________
  _
• The 3rd Czech Days for European Research, Prague,
  26 October 2005

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• The NanoRoadMap (NRM) project,
• co-funded by the European Commission (EC), is
  aimed at roadmapping nanotechnology related
  applications in three different areas
• Materials
• Health Medical Systems
• Energy
• This presentation is related to the Energy
  sector.
• It is based on 4 draft roadmaps elaborated by
  Ottilia Saxl, CEO of The Institute of
  Nanotechnology (IoN), UK, and her team.
• It also utilizes the Sectoral report on Energy
  elaborated earlier within the NRM project by Esko
  Kauppinen from VTT Technical Research Centre of
  Finland.

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• List of energy-related applications of
  nanotechnology
• Solar cells ENERGY CONVERSION
• Fuel cells
• Thermoelectricity
• Rechargeable batteries ENERGY STORAGE
• Hydrogen storage
• Supercapacitors
• Insulation ENERGY SAVING
• Glazing technology for insulation
• More efficient lighting
• Combustion
• For details see the Sectoral report ENERGY on
  www.nanoroadmap.it

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• Solar cells
• Use
• Electricity production for homes and villages in
  remote areas without a connection to the
  electricity grid
• Powering electronic equipment in wireless
  applications
• Function
• Direct transformation of light in electric energy
• Principle
• Creation of electron-hole pairs by absorption of
  light and their separation on barriers
• Functional materials
• Predominantly silicon (single-crystalline,
  poly-crystalline, amorphous, thin films)
• Thin film copper indium diselenide (CIS),cadmium
  telluride (CdTe)

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• Gallium arsenide (GaAs)
• Dye sensitised cells (DSC)
• Main production problems
• High efficiency materials are costly.
• Cheap materials show low efficiency.
• Impact of nanotechnology
• Nanoparticles, thin films, nanostructures and
  nanoporous materials have a large ratio of the
  surface to the bulk. This property has made them
  attractive for research leading to an improvement
  of the solar cells efficiency. Research topics
• Thin film solar cells
• Dye sensitised silicon solar cells
• New dyes for DSCs
• Light absorbing nanomaterials in electrically
  conductive polymers
• Nanostructures (quantum wells and quantum dots)
  embedded in different inorganic and organic solar
  cells
• Silicon or germanium nanocrystals as luminescence
  convertors

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• Experts opinion
• At present nanotechnology impact on solar cells
  is in the basic research phase.
• Thin films are seen as the most promising area
  for solar cells. By 2009 first applications and
  by 2014 current applications are expected.
• Solar cells incorporating nanocrystalline
  materials is the further technology which can
  reach commercial applications by 2014.
• Technologies including dye-based cells, quantum
  dots, fullerenes and carbon nanotubes are not
  expected to have applications by 2014.

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• Thermoelectricity
• Use
• Thermoelectric modules (featured with no moving
  parts, small size and light in weight) have been
  widely used for cooling, heating or electric
  power generation within medical, industrial,
  consumer, laboratory, electro-optic,
  telecommunications, military etc. areas.
  Refrigerators or power generator to reuse waste
  heat are examples as well as tiny generators
  reacting on the body heat.
• Function
• Transformation of thermal energy into electricity
• Transformation of electric energy into thermal
  energy (heat, cold)
• Principle
• A junction of two materials having different
  thermal conductivities exposed to a thermal
  gradient is a source of electric current.
• Passing electric current through such a junction
  results in cooling or heating.

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• Functional materials
• TE materials should have low thermal
  conductivity, high electrical conductivity and
  high Seebeck coefficient (in mV/K).
• Impact of nanotechnology
• Nanomaterials and nanostructures decrease thermal
  conductivity, increase electrical conductivity
  and improve thermo power possibility ZT. Research
  topics
• Super lattice structures BiTe /SbTe
• Bi nanowires
• Bi-Te compounds
• New materials (skutterudites, clathrates)
• Experts opinion
• Nanotechnology will play an important role in
  thermoelectricity applications by 2014

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• New materials with high ZT will be identified and
  developed by 2009 with first applications
  (energy generation from waste heat in vehicles)
  by 2014.
• The types of new materials are expected to be
  thin films, nanocrystalline materials,
  nanoparticles, nanowires and superlattices, with
  the thin films and nanocrystalline materials
  expected to be first into application.

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• Rechargeable Batteries and Supercapacitors
• Use
• Source of electrical energy in remote areas and
  for portable electronics, computers and cameras
• Function
• Storage of electrical energy
• Principle
• Batteries store electrical energy in a chemical
  form.
• Supercapacitors store electrical energy as the
  charge of electrons in an electrochemical double
  layer on the surface.
• Functional materials of the commercial products
  
• Batteries - lithium-ion, nickel-cadmium (NiCd),
  nickel-metal-hydride (NiMH) and Li-polymer
• Supercapacitors carbon, metal (nickel,
  manganese, ruthenium, iridium) oxides, electron
  conducting polymers

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• Main production or functional problems
• Batteries can store lots of energy but the charge
  and discharge times are long. Lifetime is short.
  Wastes contain hazardous materials.
• Conventional capacitors can be charged and
  discharged very quickly but store little energy.
• Supercapacitors offer combination of good
  properties of batteries and capacitors, i.e. can
  store moderately high energy and can be
  discharged moderately quickly.
• Impact of nanotechnology
• Nanocrystalline materials and nanotubes greatly
  improve power density, lifetime and
  charge/discharge rates in batteries.
• Nanotubes are used to replace the normal graphite
  of lithium-graphite-electrodes.
• A new class of materials known as aerogels made
  of 10 nm particles creates a highly porous
  structure suitable for electrodes and battery
  structures.

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• In supercapacitors instead of metal plates,
  porous carbon electrodes are used. The extremely
  small pores give the material very large active
  internal surface.
• For the same reason multi-walled carbon nanotubes
  as well as nanoporous metal (iron, nickel,
  molybdenum) oxides are used.
• Experts opinion
• Nanotechnology is expected to play an important
  role in rechargeable batteries and
  supercapacitors as early as 2009.
• The main RD focus is expected to be on electrode
  development with some on electrolytes.

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• Heat Insulation/Conductance
• Use
• Insulating materials keep the temperature
  constant in an enclosed space
• Function
• Thermal insulation provides a resistance to the
  heat flow (heat conduction, convection,
  radiation) through the insulation material.
• Principle
• Low thermal conductivity materials (fibre glass,
  rock wool, porous materials, air) prevent heat to
  flow through the insulating barrier.
• Reflective surfaces and coatings reflect heat
  coming from outside or inside back.

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• Impact of nanotechnology
• Particles and pores of aerogels are smaller than
  the wavelength of light. Though very expensive
  they are suitable for insulation due to their low
  conductivity, low density, high porosity, high
  surface area and high dielectric constant.
• Glazing technology is based on large area, low
  cost, multilayer thin film coatings. Smart
  Glazing terms a glass that reacts to its
  environment by altering its transparency and
  opacity. Smart Glazing can be classified as
  thermochromic, photochromic, electrochromic or
  gasochromic according to the environmental
  impact. Nanocoatings are made of indium-tin-oxide
  , ZnO, WO3, V2O5, LiNiO2 etc.
• Experts opinion
• Nanoparticles and thin films are expected to play
  the main role in electrochromic (switchable)
  coatings for glazing products.