Keywords and Phrases
Catalyst; Li-Air Battery; Metal Oxide; Nanoscale
"The dissertation work focuses on research and development of durable nanoscale catalysts and supports for rechargeable Li-air batteries that use aqueous catholytes. Transition metal oxides, TiO2 and Nb2O5 in particular, were prepared from a sol-gel process in the form of nanocoatings (5~50 nm) on carbon nanotubes (CNTs) and studied as catalyst supports. Carbon doping in the oxides and post annealing significantly increased their electronic conductivity. Pt catalyst on the support with TiO2 (Pt/c-TiO2/CNTs) showed a much better oxygen reduction reaction (ORR) activity than a commercial Pt on carbon black (Pt/C). Negligible loss (< 3%) in ORR activity was found in Pt/c-TiO2/CNTs as compared to more than 50% loss in Pt/C, demonstrating a significantly improved durability in the developed catalysts. However, Pt/c-Nb2O5/CNTs was found to be worse in ORR activity and durability, suggesting that c-Nb2O5/CNTs may not be a good support.
CNTs have fibrous shape and would provide a unique porous structure as electrode. Their buckypapers were made and used to support catalysts of Pt and IrO2 in the cathodes of Li-air batteries with sulfuric acid catholyte. At low Pt loading (5 wt.%) without IrO2 on the buckypaper cathode, the Li-air cell achieved a discharging capacity of 306 mAh/g and a specific energy of 1067 Wh/kg at 0.2 mA/cm2. A significant charge overpotential reduction (~ 0.3 V) was achieved when IrO2 was also used to form a bifunctional catalyst with Pt on the buckypapers. The round trip efficiency was increased from 72% to 81% with the bifunctional cathode, demonstrating a higher energy conversion efficiency"--Abstract, page iv.
Ludlow, Douglas K.
Smith, Joseph D.
Chemical and Biochemical Engineering
Ph. D. in Chemical Engineering
United States. Department of Energy
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Increasing Pt oxygen reduction reaction activity and durability with a carbon-doped TiO2 nanocoating catalyst support
- Carbothermal synthesis of titanium oxycarbide as electrocatalyst support with high oxygen evolution reaction activity
- A hybrid Li-air battery with buckypaper air cathode and sulfuric acid electrolyte
- Increasing round trip efficiency of Hybrid Li-air battery with bifunctional catalysts
- Synthesis of niobium oxide-carbon nanotubes supported Platinum for oxygen reduction reaction
xii, 149 pages
© 2013 Kan Huang, All rights reserved.
Dissertation - Open Access
Electronic OCLC #
Huang, Kan, "Nanoscale metal oxide and supported metal catalysts for Li-air battery" (2013). Doctoral Dissertations. 2497.