An Introduction to Fuel Cells and NanotechnologyPotential & Challenges

OpenCraft Technical Seminar October 2007

bySami Mardini

2Content

Fuel Cells

Basic Principles

Advantages

History

Applications

Commercialization

Questions

Nanotechnology

Definition

Product Applications

Nanomaterials production Methods

Questions

3The Hype Cycle 1. "Technology Trigger"The "technology trigger" or breakthrough, product launch or other event that generates significant press and interest.

2. "Peak of Inflated Expectations"A frenzy of publicity typically generates over-enthusiasm and unrealistic expectations. There may be some successful applications of a technology, but there are typically more failures.

3. "Trough of Disillusionment"Technologies fail to meet expectations and quickly become unfashionable. Consequently, the press usually abandons the topic and the technology.

4. "Slope of Enlightenment"Businesses continue through the "slope of enlightenment" and experiment to understand the benefits and practical application of the technology.

5. "Plateau of Productivity"A technology reaches the "plateau of productivity" as the benefits of it become widely demonstrated and accepted. The technology becomes increasingly stable and evolves in second and third generations. The final height of the plateau varies according to whether the technology is broadly applicable or benefits only a niche market.

X Fuel CellsNanotechnology X

4Environmental Outlook

year1000 1200 1400 1600 1800 2000

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340Global CO2 levels

Source: Oak Ridge National Laboratory

2004: 378 ppm

Projections:

500-700 ppm by 2020

Industrial Revolution

5Basic Fuel Cell

Fuel

e-e-

Membrane

Air

Overall: Fuel In Electricity Out

6Basic Equations

Wel = G = nF E where F is Faraday's constant (96,487 coulombs/g-mole electron), and E is the ideal potential of the cell.

G = H TS where H is the enthalpy change and S is the entropy change. The total thermal energy available is H. The available free energy is equal to the enthalpy change less the quantity TS which represents the unavailable energy resulting from the entropy change within the system.

A+BcC+D

G = cG+GGG

7How a Fuel Cell Works

H2 2H+ + 2e- O2 + 2H+ + 2e- H2OFuel

Car / Home / Laptop

C

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e-e-

Electrolyte

H

Oxidant

By-productBy-product

Overall: H2 + O2 H2O

+

8Why Fuel Cells?

Higher EfficiencyX 40-90%*

Clean EnergyX No CO2 emissions on H2

X

9Applications

Back-upPower

PortableElectronics Automotive

DistributedGeneration

Military & Aerospace

AuxiliaryPower

Fuel Cells1 W 1 MW

10

US Electricity Flow

Energy Information Administration- 2006 Annual Energy Review

2005 Electricity Flowin Quadrillion BTU

High Efficiency FC High Efficiency FC Distributed Generation Distributed Generation reduces conversion losses reduces conversion losses and eliminates T&D lossesand eliminates T&D losses

65% lost energy due to low efficiency generation12.7% lost electricity due to transmission and distribution

11

Fuel Cell HistoryLots of Prototypes, No Mass Adoption

Sir William Grove-1st fuel cell

1839

1889

Ludwig Mond &Charles Langer- coin fuel cell

Francis T. Bacon-1st alkalinefuel cell (AFC)

1932

1955

General Electric- 1st polymer fuel cell (PEMFC) inGemini space craft

1959

WestingHouse-1st solid oxidefuel cell (SOFC)

1962 1964

Allis-Chalmers-5 kW phosphoricacid fuel cell (PAFC)

Texas Instruments- 100 W MoltenCarbonate FuelCell (MCFC)

1965

1967

Union Carbide-AFC poweredmotorcycle

1979

United Technologies- 40 kW PAFC

Ballard Systems-100 kW PEMFCtransit bus

1993

1997

1997

Daimler Benz &Honda

- PEMFC cars

Power Corporation- 250 kW MCFC

Toshiba- 1 W PEMFC

2005

12

Types of Fuel Cells

Fuel Cell Electrolyte Major Drawbacks

AFC - 1930 Alkaline (liquid) Needs pure oxygen, corrosive liquid

SOFC - 1937 Solid oxide (solid) Expensive, thermal cycling

PAFC - 1959 Phosphoric acid (liquid) Expensive, corrosive liquid

PEMFC - 1961 Polymer electrolyte membrane (liquid/solid composite)

Expensive, short lifetime

MCFC - 1957 Molten carbonate (liquid) Expensive, corrosive liquid

SAFC - 2004 Solid acid (solid) As yet to be determined

13

Solid Acid Electrolytes

Intermediate salts and acids 1Cs3PO4+ 2H3PO4 3CsH2PO4

PropertiesX Solid state proton conductivity

X Impermeable

50 100 150 200 250 3001E-8

1E-6

1E-4

0.01

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Temperature (C)

Polymer (Nafion)

Solid Acid (CsH2PO4)

superprotonic

normal phase transition

Solid Acid Conductivity

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Solid Acid Electrolytes

too cold

too hot

minimum conductivityfor fuel application

optimal operating

temperature

operating fuel cells at optimal temperatures

expensive catalysts

inefficientcooling

expensive materials

poor thermal cycling

low cost materials

simpler system

0 200 400 600 800 1000

1E-3

0.01

0.1

1Solid Oxide

YSZ

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Temperature ( C)

Polymer (PEM)Nafion

Solid AcidCsH2PO4

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Alternative Fuels

HydrogenX Cleanest but lowest energy density

X Issues in production, distribution and storage

X Massive new infrastructure will be needed for automotive applications

RenewablesX Biofuels: Ethanol, Biodiesel

X May be carbon neutral

Opportunity FuelsX Industrial process byproduct gases

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0

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Gasoline Ethanol Methanol LiquidHydrogen

CompressedHydrogen

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Energy Density of Fuels

Liquid fuels have more than 7 times the energy density of compressed hydrogen fuelLiquid fuels have more than 7 times the energy density of compressed hydrogen fuel

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Fuel Cell Adoption Curve assuming price & performance targets are met

$10

$100

$1,000

$10,000

$100,000

1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018

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Automotive

R&D Prototype

Military

Back-up Power

APU

Residential

Industrial Commercial

Consumer Portable

Central Generation

Timeline

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Core Product

Stack SystemCellElectrolyte

from electrolytes to stacks

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Telecom BackUp Power

5 kWPEM

System

FuelStorage

Battery bank

Diesel Genset

+Vs.

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Long Haul Diesel Truck APU

Class 8 trucks with sleeper cabs. APU provides power for heating/cooling eliminating overnight idling. Expect legislation to be introduced in 2010 timeframe.

Truck Idling (Argonne National Lab Study) 1,830 hours/year idling per truck (6 hours/day)

458,000 trucks travel >500 miles from base per day

838 million gallons of fuel per year for idling

140 g/hour NOx; 8,200 g/hour CO2

21

SummaryFuel Cellsand Solid Acid Fuel Cells

Efficient energy conversion devices

Mass adoption held up for over half century by high cost/low durability

Solid Acid Electrolytesfirst new fuel cell electrolyte in 40 yrs

X Excellent material properties for fuel cells

Fuel cells part of the future energy landscape

X More efficient use of standard fuels

X Enabling technology for carbon free and carbon neutral energy cycles

22

Fuel Cells

Questions ?

23

Increase PerformanceApproach: Nanoparticle Electrolyte

catalyst

catalyst

3000x 10000x

Size mismatch in current electrodes leads to small active SAnano-sized electrolyte particles dramatically increase active SASize mismatch in current electrodes leads to small active SA

nano-sized electrolyte particles dramatically increase active SA

Optimized electrode

Nanoparticle catalyst

Percolatingelectrolyte & catalystparticles

Non-ideal electrode

Large, isolated electrolyte particle

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Active Catalytic Surface AreaA Physical Picture

True triple phase boundary

Point junctions between electrolyte and catalyst

Limited by electrolyte surface area

Pt

CsH2PO4 O2 (gas)H+

H2O (gas)

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Active Electrolyte Surface AreaSurface area a function of particle size

10 100 1000 10000

0

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0.4Pt:C 90 m2/g

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CsH2PO4 Particle Radius / nm

Pt black 28 m2/g

currentstandard

Need to increase electrolyte surface area to increase active surface area

Typical catalyst-electrolyte surface areas greater than 20 m2/g

Solid acid surface area less than 2 m2/g (500 nm)

Need to decrease particle size by an order of magnitude!

Need to decrease particle size by an order of magnitude!

Surface Area as a Function of Particle Size

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0 2 4 6 8 100

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Inverse average particle size / m-1

Nano-Particle ElectrolyteSolid acid particle size effect

Dramatic performance increases due to increasing catalytic activity with decreasing electrolyte particle size.

Dramatic performance increases due to increasing catalytic activity with decreasing electrolyte particle size.

Today1000 nm

Milestone 1180 nm

Power Density as aFunction of Particle Size

27

What is Nanotechnology ?

The application of nanoscale materials and properties to

X improve performance of existing materials or products

X create useful size dependent properties

X create new products

The development of methods and processes to produce nanomaterials

Identifying the chemical and physical changes that occur at the nanoscale.

Developing new tools to measure and analyze highly miniaturized structures.

28

Just Small is Not Enough!

Dimensions have to play a critical role ( typically in the range of 1 to 100 nanometers)

Some materials when smaller than 100 nm exhibit useful and different chemical and physical properties than bulk

29

Examples of size dependent properties

Catalytic X how the material enhances chemical reactions

ElectrochemicalX how the material transfers electrons to other chemical constituents

Magnetic propertiesX how the electrons interact to induce magnetic poles

Optical properties X how the material interacts with light (e.g., its color)

Difficult to predict at what size a particular material will transition from bulk to size-dependent properties. X Threshold is different for each material and each property.

For example, nanoscale gold will have different colors throughout the nanoscalesize range, but the size-dependent catalytic properties do not dramatically change until gold features are smaller than five nanometers.

30

High Refractive Index Encapsulant for LED Lighting. Over 80% of the light emitted from blue-LED chip is lost

X Due to a large difference in the refractive index between LED bare chip (semiconductor or organic) and encapsulant

n2

n1Emission Layer

TIR

n1 > n2

LED ChipLED Chip

EncapsulantEncapsulant

31

High Index Encapsulation Solution For Brighter LED

Light extraction efficiency of LED encapsulant increases with hiLight extraction efficiency of LED encapsulant increases with higher refractive gher refractive index, which approaches the RI of LED (2.7). RI of starting polyindex, which approaches the RI of LED (2.7). RI of starting polymer is 1.5mer is 1.5

32

Medical Applications

Targeted and IntelligentDrug Delivery

X Nanoparticle drug carriers coated with nano-sensors

recognize diseased tissues

attach to them

release drug exactly where needed.

X enter damaged cells and release enzymes to auto-destruct or auto-repair

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Nanoparticle ProductionOverview of Approaches

CompositionX Requires gaseous/liquid precursorsX Gas phase enables direct synthesisX Contamination varies with process

Particle size and distributionX Depends on quench conditionsX Depends on reactant densityX Initial result generally retained

CompositionX Reaction chemistry and precursorsX Broad range of possible synthesis routesX By products/contamination

Particle size and distributionX Large variation in particle size distributionsX Difficult to reach/retain nano-scaleX Possible post processing required

Production Methods

Gas PhaseNucleation

Solid StateSynthesis

PlasmaVaporization

Flame/Spray Pyrolysis

AerosolTechniques

Solution -Precipitation

Solution -Suspension

MechanicalMilling

Slide Courtesy of NanoGram Corporation

34

Nanoparticles Production Challenges

Size Control

Size Distribution

Purity

Throughput

Scalability

Agglomeration

Ecomomics

35

Laser-Driven Nanoparticles Synthesis

36

Nanotechnology Summary

Great Science

X Multi-disciplinary: chemistry, physics, biology, engineering

Great Potential

X Energy, Electronics, Medicine, Environment, Security,..

Significant Time and Investment Still Needed

X Create meaningful successes

X Expectations Management

37

Nanotechnology

Questions ?

An Introduction to Fuel Cells and NanotechnologyPotential & ChallengesContentThe Hype CycleEnvironmental OutlookBasic Fuel CellBasic EquationsHow a Fuel Cell WorksWhy Fuel Cells?ApplicationsUS Electricity FlowFuel Cell History Lots of Prototypes, No Mass AdoptionTypes of Fuel CellsSolid Acid ElectrolytesSolid Acid ElectrolytesAlternative FuelsEnergy Density of FuelsFuel Cell Adoption Curve assuming price & performance targets are metCore ProductTelecom BackUp PowerLong Haul Diesel Truck APUSummaryFuel CellsIncrease Performance Active Catalytic Surface AreaA Physical PictureActive Electrolyte Surface Area Surface area a function of particle sizeNano-Particle Electrolyte Solid acid particle size effectWhat is Nanotechnology ?Just Small is Not Enough!Examples of size dependent properties High Refractive Index Encapsulant for LED Lighting.High Index Encapsulation Solution For Brighter LEDMedical ApplicationsNanoparticle Production Overview of ApproachesNanoparticles Production ChallengesLaser-Driven Nanoparticles SynthesisNanotechnology SummaryNanotechnology