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Fabrication and Evaluation of PTFE-Bonded Platinum Electrodes for Space Flight Application. Joshua Johnston, South Carolina Governor’s School for Science and Mathematics Dr. Xinyu Huang, University of South Carolina, Department of Mechanical Engineering. Background.
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Fabrication and Evaluation of PTFE-Bonded Platinum Electrodes for Space Flight Application Joshua Johnston, South Carolina Governor’s School for Science and Mathematics Dr. Xinyu Huang, University of South Carolina, Department of Mechanical Engineering
Background • Oxidation-Reduction Reaction • Anode • Cathode • Electrolyte Figure 1. Fuel Cell Schematic
Background • NASA has developed hydrogen-oxygen fuel cells for space flight application • Supply electrical power and potable water during space flight. • Polymer electrolyte membrane fuel cells (PEMFC’s) • Provides the long-term stability and durability
Background • Proton conductive membranes are interfaced with an electrode • Unsupported platinum catalyst for durability. • Platinum black • Polytetraflouroethylene(PTFE) to manage water
Purpose • To develop membrane electrode assemblies that meet operation standards set by NASA, which are 200 mA/cm2 with hydrogen and oxygen under 30 psi (relative) pressure. • The long term objective of this project is to develop high performance membrane electrode assemblies that can meet or exceed NASA’ s performance objectives.
Methods • Catalyst Formulation • Catalyst Depositon Figure 3. Catalyst Deposition Figure 2. Ultrasonic Dispersion
Methods (Continued) • Elimination of surfactants • Ionomer Deposition Figure 5. GDE with ionomer coating Figure 4. Heating GDE’s
Methods (Continued) • Electrode Attachment • Cell Assembly Figure 7. Fuel Cell Assembly Figure 6. Heated Compression of GDE and ionomer.
Methods (Continued) • Cell Testing Figure 8. Fuel Cell Testing
Results Figure 9. Polarization Curve of NASA 001
Results (Continued) Figure 10. Polarization Curve of NASA 002
Results (Continued) Figure 13. Cyclic Voltammetry of Nasa 001
Discussion and Conclusion • Pressurized performance • Water transport issues • Platinum loading • PTFE loading • Hydrogen Crossover
Discussion and Conclusion (continued) • In conclusion the performance standards set by NASA were not achieved in this study. However, this study did serve as a good basis for future attempts.
Future Research • Future research endeavors will attempt to optimize the fabrication of the GDE’s including: platinum loading, PTFE loading, and deposition of both the catalyst and ionomer.
Acknowledgements • South Carolina Governor’s School for Science and Mathematics • University of South Carolina • William Rigdon • Joshua Sightler • Dianna Larabee • Mr. LaCross