Jerry M Woodall National Medal of Technology Laureate Epstein Distinguished Professor of ECE

1. SPLITTING ANY KIND OF WATER WITH GLOBAL-SCALE, EARTH-ABUNDANT, LIGHT, RECYCLABLE METALS TO MAKE HYDROGEN, HEAT AND POTABLE WATER ON DEMAND Jerry M Woodall National Medal of Technology Laureate Epstein Distinguished Professor of ECE Purdue University

2. Why isn’t there a global scale hydrogen energy economy? • Small volume energy density • High pressure gas and low temperature liquid storage expensive and dangerous • Hydrogen transport dangerous and expensive Solution: use a safe, cheap, earth-abundant high energy density material for storage and transport that can react with water to make hydrogen on demand Is there such a material? Yes! It’s ALUMINUM! If aluminum could split water the chemistry would be: 2Al + 6H2O  3H2 + Al2O3:3H2O

3. Aluminum has the highest volumetric energy density of anything on the chart and a higher mass energy density than ethanol, methanol or bituminous coal!

4. Mass Energy Densities of Interest • As hydrogen from splitting water: • 1 Kg H2: 142 MJ = 39.4 kWh combustible energy • 1 Kg Al makes 111 g of H2 from 2 Kg of H2O = 4.4 kWh • 1 gal (10 Kg) Al makes 44 kWh as hydrogen • 1 gal. diesel: 37 kWh • 1 gal. liquid hydrogen: 10 kWh • As heat from splitting water: • 1 Kg Al: 4.4 kWh • Total energy, 1 Kg Al: 8.8 kWh (1Kg coal: 6.7 kWh!) •Energy to electrolyze alumina to 1 Kg of Al: 12.9 kWh•Total energy efficiency: (8.8/12.9) x 100 = 68% • H2 energy efficiency: (4.4/12.9) x 100 = 34%

5. Technology sustainability & large scale use World Supply: • Al “reserve” in the planet’s crust: about 1013 Kg (as Al); 1.2 x 1012 Kg of H2 made by splitting water = 5 x 1013 kWhrs of H2 energy • Current worldwide annual Al production: 32 billion Kg from bauxite; • 400 billion Kg of scrap impure elemental Al; amount needed to supply 12% US annual energy consumption of about 100 quad BTU. Since all Al that is converted to an oxide can be recycled back to metallic Al via electricity from any source, Al is a global scale alternative energy storage material with almost no carbon footprint.

6. WHAT CAN WE MAKE? • Buy scrap or metallurgical grade, i.e. cheap, Al, melt it with Ga and Sn, then cool it to make solid, “bulk like” Al rich alloys up to 93 wt% solid Al grains, and 6.2 wt% Ga, and 0. 8 wt% Sn liquid in the grain boundaries that splits any kind of liquid water, e.g. sea water, dirty water and polluted water, at between 20 C and 100 C and make H2, heat, including superheated steam, on demand and aluminum hydroxide powder • Buy 95% Al, 5% Sn vendor alloy, contact with a liquid mixture of 7 wt% Ga and 1 wt% Sn, and then with water; this splits any kind of liquid water at temperatures between 20 C and 100 C and make H2, heat, including superheat steam, on demand and aluminum hydroxide powder • Recover/separate inert Ga and Sn from hydroxide powder and recycle indefinitely

8. A sample of Al-GalInSn* splitting water Using scrap Al and recovering the GaInSn component, the cost/kWh of our hydrogen/compared to other fuels: Coal: $0.004 Natural Gas: $0.06 Al: $0.10 Gasoline: $0.09 (at $3.00/gallon) Li ion battery: $4.00 *GaInSn is liquid at room temperature

9. 2Al(GaInSn) + 6H2O* 3H2 + 2Al(OH)3 + GaInSn 3H2 + 3/2O2 3H2O; we get back half the water when we use the H2; we get rest of the water + the Al back via smelting; the GaInSn is inert * Including salt water 2 Al 2 Al(OH)3 + heat Al2O3 + 3 H2O + electricity Bottom line: You get all the water back as potable water!

10. Alloy How it works! Water Al-Ga grain Legend: = Aluminum = Ga-In-Sn = Hydroxide = Hydrogen gas At room temperature, the Ga-In-Sn phase is liquid! The solid Al “grains” are able to dissolve into and move freely through the liquid phase. Al near the surface contacts the water interface. The ensuing exothermic reaction produces hydrogen as the Al is oxidized. This reaction proceeds until all the Al grains split the water into hydrogen gas and aluminum hydroxide

11. Abundance: Al: crustal abundance – 8% Ga: crustal abundance – 0.002% Sn: crustal abundance – 0.0002% Sustainability: Al: annual production – 32 billion kg Ga: annual production – 184 million kg Sn: annual production – 165 million kg Therefore, as long as the Ga and the Sn are recycled there is no Ga abundance or production problem

12. The Aluminum-Hydrogen Cycle Aluminum Hydroxide Energy Source (wind, solar, nuclear, geothermal, etc) (-12.9 kWh/kg-Al) Aluminum Alloy Heat (+4.4 kWh/kg-Al) Reaction CO2 Sequestered Water Hydrogen (+4.4 kWh/kg-Al) Water Application (fuel cell, combustion engine) Energy

13. Example applications: Replace batteries with a Ga-Al-H20/fuel cell system for high energy density electric power applications: • emergency/stand-by power (AlGalCo) • electric wheel chairs, golf carts, utility vehicles • PDAs, Laptops, etc. • hybrid and fuel cell powered cars Other applications: • Stirling engines • replace gasoline for HEVs (GM Volt) • liquid fuel multiplier, e.g. diesel enrichment • trains, boats, ships, subs, trucks • large boats and other maritime applications • off-grid/remote power + desalinated/potable water! • integrated utilities with solar farms/wind turbines

16. Enabling Wind or Solar as Base Load Electricity Generation Capacity • Target cost: $0.10/kWhr, assuming 40x alloy recycling • All required technologies are known • Primarily an Engineering Development Project • Enables Environmentally Sound and Secure Electricity

17. Enabling Wind or Solar as Base Load Electric Power Model Flow Diagram alumina, Ga,In,Sn + H20 alumina electrolysis 12.9 kW-Hrs/Kg Al Fuel Cell or Gas Turbine/Generator Electricity CONSUMER Heat, 4.4 kWh/Kg-alloy 24/7 or on demand Steam Turbine H2, 4.4 kWh/Kg-alloy 24/7 or on demand H20 intermittent electrical power, e.g. solar or wind reaction tank, 95-5 alloy, and controls H20 component separation H20 Ga,In,Sn recovery 95-5 alloy regeneration

18. CAN BE DONE FOR $1/GAL OF WATER AND $0.34/kWh OF ELECTRICITY

19. THE BOTTOM LINE: ALUMINUM! • A GLOBAL-SCALE, EARTH-ABUNDANT, HIGH ENERGY DENSITY STORAGE MATERIAL FOR SPLITTING ANY KIND OF WATER TO MAKE HYDROGEN, HEAT AND POTABLE WATER ON DEMAND • ONCE YOU BUY IT, IT IS YOURS FOREVER; UNLIKE FOSSIL FUELS IT STAYS IN THE ENERGY SYSTEM.