Thin Film Fuel Cells and Hydrogen Storage Materials for Solar Energy Application

Center for Advanced MaterialsUniversity of HoustonNASA Research Partnership Center

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Thin Film Fuel Cells and Hydrogen Storage Materials for Solar Energy

Application

Alex Ignatiev1,2, Ainur Issova2, Mukhtar Eleuov2

1 Center for Advanced Materials

University of Houston,

Houston, TX 77204-5004

2 Institute for Physics and Technology

Almaty, Kazakhstan

Almaty, 2011


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Solar Energy Utilization

• Sunlight Required

• Energy Storage Needed for Nighttime and Cloudy Operation

• Store Energy in Hydrogen..• Electrolyze Water

• Utilize Hydrogen Fuel Efficiently


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• Liquid • Cold – 22K• 5 wt% - Adequate• EXPENSIVE…..

Hydrogen Storage Options

• Gas• High Pressure- 200-500 bar• 2-3 wt% - Too Little Hydrogen• High Pressure Danger

• Hydrides

• ~ 1 wt% - Too Little Hydrogen in Cycle


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Volume for Storage of 5 kg H2 in Different States (Equivalent to 20 L Gasoline)

No Effective way of Storing Hydrogen…..• Polymer Nanostructures…. ??


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Nanostructured Polymers

• Polyanaline Nanotubes

• Conducting Polymers

• Nanotube pores

• High surface area

Polyaniline Nanotubes


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• PANI 2.5-3 wt% H2 Uptake

•Tested to 12+ Cycles-no deg

Polyaniline (PANI) Charge & Discharge

• Charge at 300psi for 2 hours

• Multiple Charge – Discharge Cycles

• Mass Spectrometer Read-out

• Good Hydrogen Storage and Cycling

20 40 60 80 100 120 140

0.01.0x10-72.0x10-73.0x10-74.0x10-75.0x10-76.0x10-77.0x10-78.0x10-79.0x10-71.0x10-61.1x10-61.2x10-6

Discharged E

Charged ECharged A

Discharged D

Discharged B

Discharged A

Charged D

Charged B

To

rr

Temp.o

C


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Volume for Storage of 5 kg H2 in Different States (Equivalent to 20 L Gasoline)

Polyaniline

Polyaniline - Promising Hydrogen Storage System


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Efficient Use of Hydrogen Fuel

Hydrogen for Transportation

• Internal Combustion Engine

• Not Use – Explosive Reaction

• Still form NOx

• Use Fuel Cell

• Electrochemical Reaction

• OK - No NOx formed…..

• Only WATER….


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What is a Fuel Cell?A device that generates electricity by combining fuel and oxygen in an electrochemical reaction.

Advantages

• High energy conversion efficiency

• Minimal environmental impact

• Stackable to reach very high power output

• Reduced noise level

1/2O2

H2O2e- Fuel

Oxidant

Anode

Electrolyte

Cathode

2e-

O2-

O2-

O2-

H2


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Solid Oxide Fuel Cell

• Hydrogen and oxygen reactants

• ZrO3 electrolyte

• Nickel anode

• Operating temperature is 900-1000°C

• Encapsulation materials challenges

• High materials costs

But, High Efficiency > 60%

• High market cost

• How to Reduce market cost …. ??


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Apply Thin Film Materials Expertise to SOFC Challenges

• Develop New Design: Thin Film Solid Oxide Fuel Cell

• Thin Film Heterostructure Design

- Thin electrolyte- lower temperature operation

- Atomically ordered films/interfaces- lower resistance

• Microelectronics Processing - Economies of Scale

• Lower Fabrication Cost

• Smaller Size

• Lower Cost


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Thin Film SOFC Heterostructure Growth

• Thin Film Atomically Ordered YSZ Electrolyte

• Reduce Internal Defects

• Reduce Interface Defects

Target

Plume

Beam

VacuumChamber

Substrate

Heater

Excimer

Laser

FocusLens

Oxygen

Target

Plume

Beam

VacuumChamber

Substrate

Heater

Excimer

Laser

FocusLens

Oxygen

Epitaxial Growth

• Pulsed Laser Deposition of Epitaxial YSZ Film

on Crystalline Nickel Foil Substrate


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Thin Film Heterostructure Solid Oxide Fuel Cell

Total Cell Thickness

~ 20-25 m thick

Porous LaSrCoO3 Cathode ~ 1 m thick

Yttria Stabilized Zirconia Thin Film Electrolyte

~ 0.1 - 1 m thick

Nickel Anode~20m thick

Fuel

Oxygen/Air

Ni Foil Anode NOT Porous


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• Electrochemically Etched Nickel Anode

• 60 m Etched Pores

•Nickel Side Electro-etch

Ni Porosity - Microelectronics Photolithography / Etching


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TFSOFC I vs. V as a Function of Temperature

Hydrogen / Air - Polycrystalline Single Cell

0 5 10 15 20 25 30 350.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20 25 30 350 5 10 15 20 25 30 350.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20 25 30 350 5 10 15 20 25 30 350.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20 25 30 350 5 10 15 20 25 30 350.0

0.2

0.4

0.6

0.8

1.0

0 5 10 15 20 25 30 350

10

20

30

40

50

60

70

80

90

100

110

120

480oC

I (mA)

P (

mW

/cm

2 )

570oC

V (

V)

I (mA)

555oC

I (mA)

520oC

I (mA)

Thin Film Micro SOFC


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• Solid Oxide Fuel Cells Have Nickel Anodes

• Nickel Excellent Catalyst for Hydrocarbon Reduction

• BUT…….‘Coking’ at High Temperatures…. > 600 C

Thin Film Heterostructure SOFC Advancement

• However… Micro Fuel Cell Operates at 500 C – NO Coking…!

• Hydrocarbon Fuel Operation at ~60% Efficiency….

• Methane/Methanol

• Ethane/Ethanol


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Thin Film Fuel Cell Stack

• Require ~ 100V to 200V Operation• Series Connection of Cell Elements

• Interconnect Required

• Stack Individual Cells Together in Series

• Work in Collaboration with Institute for Physics and Technology, Almaty

• Advance Technology• Finalize Product•Technology Transfer• Economic Growth


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Thin Film Fuel Cell Stack Components

Cell Element

Oxidant Flow

Fuel Flow

Interconnect


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Fuel Cell Stack Design (In Progress)

TFSOFC Micro-patterned Interconnect

cathode

electrolyte

anode

Fuel flow

Oxidant flow

Thin Film Heterostructure SOFC Advancement

Projected > 5W/cm3 at ~500oC


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Summary• A New Thin Film Solid Oxide Fuel Cell Design

• Efficient, Clean, Compact and Cost Efficient

• Low Temperature Operation

• Direct Use of Hydrocarbon Fuel

• Natural Gas

• Hydrogen from Dissociation of Water…????

Distributed EnergyAutomotive Energy

Strategy for Efficient, Clean Electrical Energy Generation

Thin Film Fuel Cells and Hydrogen Storage Materials for Solar Energy Application

Documents

film fuel cells

micro fuel cell

film heterostructure

film materials expertise

hydrocarbon fuel operation

hydrogen storage materials

energy storage

sofc challenges