Nanotechnology for Energy Storage

1. Nanotechnology for Energy Storage Dr. Scott Gold Asst. Prof. Chemical Engineering and Nanosystems Engineering Louisiana Tech University “Building Energy Systems for Tomorrow” Louisiana Tech Energy Systems Conference Nov. 5, 2009 Research Group: Steven Bearden Eric Broaddus Stephen Brown Ben Browning Joshua Hawthorne Ahmad Minhas Ravi Sekhar Brittany Wilson

2. Template Wetting Nanofabrication • Process for making arrays of nanostructures • We are one of 4 research groups in the world with expertise using this process! (The only one in the US) • Porous template defines shape • Nanostructures from many materials • Ceramics and metal oxides • Metals (platinum, palladium, gold) • Piezoelectrics (Lead zirconium titanate or PZT, PVDF) • Polymers Surface tension draws the solution into the pores. Solvent evaporates leaving behind solid precursor – this becomes our nanotubes , nanowires, or other structure Specially engineered wetting solution is applied to the template. P3HT Nanotubes That’s really nice….but what good is it??? Platinum Nanotubes

3. Energy Applications of Our Nanostructures • Fuel Cells • Proton Exchange Membranes • Catalysis • Piezoelectric energy scavenging devices • Photovoltaics • Supercapacitors • Hydrogen Storage Lets’ look at two of these…

4. NanostructuredSupercapacitors • Low energy density compared to other power sources but high power density • Rapid recharge/discharge rates • Key component in power management systems • Usually coupled with batteries and/or fuel cells • First prototype device • Gold electrodes, polystyrene dielectric • Purely electrostatic • Achieved ~7 F/g active material • Performance limited by high internal resistance

5. NanostructuredSupercapacitors • Electrochemical supercapacitors • Store charge within electrode material – similar to batteries • Best reported performance with expensive RuO2 • Polythiophenes • Both n and p type doping can be achieved • P3HT (poly-3-hexylthiophene) • Achieved over 400F/g active material! • Future plans • Continued nano-electrode characterization • Optimize electrolyte deposition • Improved prototypes Charge-discharge curve for P3HT nano-electrode

6. Hydrogen Storage • Great challenge for fuel cell vehicles • Goals: • High energy density • DOE Targets: • 6 wt.% by 2010 • 9 wt% by 2015 • Safety • Regeneration • Compressed H2 gas • Heavy tanks required • Safety issues • Metal hydrides • Some promise • Stability issues • Difficulties recharging • Ammonia borane • Stable solid in air • Soluble in common solvents • Can meet DOE goals • Chemically regenerated

7. Hydrogen Storage • Ammonia borane challenges • Chemistry not well understood • Catalyst required to lower hydrogen release temperature • Without a catalyst • Hydrogen released in 3 steps • First step ~100°C • Our thermolysis catalyst – all steps below 100°C No catalyst With our nanocatalyst

8. Hydrogen Storage • Ammonia borane challenges • Our hydrolysis catalyst – room temperature H2 • Prototype H2 generator under development • Continuing chemical characterization

9. Conclusions • Unique nanotechnology being developed at Louisiana Tech • Enabling advances in a variety of energy fields • Super capacitors • Hydrogen storage for Fuel cells • Thank you!