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Thin Film Fuel Cells and Hydrogen Storage Materials for Solar Energy Application Alex Ignatiev 1,2 , Ainur Issova 2 , Mukhtar Eleuov 2 1 Center for Advanced Materials University of Houston, Houston, TX 77204-5004 2 Institute for Physics and Technology Almaty , Kazakhstan
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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
Solar Energy Utilization • Sunlight Required • Energy Storage Needed • for Nighttime and Cloudy Operation • Store Energy in Hydrogen.. • Electrolyze Water • Utilize Hydrogen Fuel Efficiently
Hydrogen Storage Options • Liquid • Cold – 22K • 5 wt% - Adequate • EXPENSIVE….. • Gas • High Pressure- 200-500 bar • 2-3 wt% - Too Little Hydrogen • High Pressure Danger • Hydrides • ~ 1 wt% - Too Little Hydrogen in Cycle
Volume for Storage of 5 kg H2 in Different States (Equivalent to 20 L Gasoline) • No Effective way of Storing Hydrogen….. • Polymer Nanostructures…. ??
Nanostructured Polymers • Polyanaline Nanotubes • Conducting Polymers • Nanotube pores • High surface area Polyaniline Nanotubes
Polyaniline (PANI) Charge & Discharge • Charge at 300psi for 2 hours • Multiple Charge – Discharge Cycles • Mass Spectrometer Read-out • PANI 2.5-3 wt% H2 Uptake • Tested to 12+ Cycles-no deg • Good Hydrogen Storage and Cycling
Volume for Storage of 5 kg H2 in Different States (Equivalent to 20 L Gasoline) Polyaniline Polyaniline - Promising Hydrogen Storage System
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….
What is a Fuel Cell? A device that generates electricity by combining fuel and oxygen in an electrochemical reaction. 2e- H2O H2 Fuel Anode O2- O2- Electrolyte O2- Cathode 2e- Oxidant 1/2O2 • Advantages • High energy conversion efficiency • Minimal environmental impact • Stackable to reach very high power output • Reduced noise level
But, High Efficiency > 60% Solid Oxide Fuel Cell • Hydrogen and oxygen reactants • ZrO3 electrolyte • Nickel anode • Operating temperature is 900-1000°C • Encapsulation materials challenges • High materials costs • High market cost • How to Reduce market cost …. ??
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
Thin Film SOFC Heterostructure Growth • Thin Film Atomically Ordered YSZ Electrolyte • Reduce Internal Defects • Reduce Interface Defects • Pulsed Laser Deposition of Epitaxial YSZ Film • on Crystalline Nickel Foil Substrate Epitaxial Growth
Fuel Nickel Anode ~20m thick Yttria Stabilized Zirconia Thin Film Electrolyte ~ 0.1 - 1 m thick Porous LaSrCoO3 Cathode ~ 1 m thick Oxygen/Air Thin Film Heterostructure Solid Oxide Fuel Cell Total Cell Thickness ~ 20-25 mm thick Ni Foil Anode NOT Porous
Ni Porosity - Microelectronics Photolithography / Etching • Electrochemically Etched Nickel Anode • 60 m Etched Pores • Nickel Side Electro-etch
Thin Film Micro SOFC TFSOFC I vs. V as a Function of Temperature Hydrogen / Air - Polycrystalline Single Cell
Thin Film Heterostructure SOFC Advancement • Solid Oxide Fuel Cells Have Nickel Anodes • Nickel Excellent Catalyst for Hydrocarbon Reduction • BUT…….‘Coking’ at High Temperatures…. > 600 C • However… Micro Fuel Cell Operates at 500 C – NO Coking…! • Hydrocarbon Fuel Operation at ~60% Efficiency…. • Methane/Methanol • Ethane/Ethanol
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
Thin Film Fuel Cell Stack Components Cell Element Fuel Flow Interconnect Oxidant Flow
Thin Film Heterostructure SOFC Advancement Fuel Cell Stack Design (In Progress) cathode electrolyte anode Micro-patterned Interconnect TFSOFC Fuel flow Oxidant flow Projected > 5W/cm3 at ~500oC
Distributed Energy Automotive Energy 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…???? • Strategy for Efficient, Clean Electrical Energy Generation