1. Heteropoly acid Immobilization and Crosslinking in a Polymer Electrolyte Membrane for Fuel Cell Ruth Anyaeche, Andrew Motz, Mei-Chen Kuo, James L. Horan, Andrew M. Herring Renewable Energy Material Research Science and Engineering Center Department of Chemical and Biological Engineering, Colorado School of Mines Golden CO

2. CHEMISTRY OF FUEL CELL At anode: 2H2 ⇒4H + 4e At Cathode
O2 + 4H + 4e ⇒2H2O
Net Reaction
2H2 + O2 ⇒2H2O

3. Objective of Research
Heteropoly acid (HPA) attachment and cross-linking in a novel fuel cell polymer membrane
Determine how the polymerization condition is suitable for maximizing the attachment of HPA fully to the polymer solution by annealing time and temperature in the K+ and H+ form.

4. HPA is a good proton conductor at hotter and drier conditions in a fuel cell
Covalent bonding to the polymer prevents the HPA from washing out
Cross-linking improves mechanics

5. Characterization Technique
HPA (70wt%)added to polymer solution with the H+ catalyst
Anneal to further attach the HPA

6. Boil in H2O for 1 hour
Anneal each piece at different temperature and time in K+ and H+ form
Soak in H2O for 16 hours

7. Measure membrane and perform EDX to determine the %HPA immobilized.
Conductivity measurement determine membrane performance

8. After Ion Exchange – 50% HPA left Soaked in water – 40% Retained
Boiled in water – % left

9. Concentrated solution (Sample 5) at high temperature and time in K+ form but no H+ form
Dilute Solution (Sample 21 and 22) annealed at different temperature and time in K+ form and H+ form

10. Different temperature of 92RH at 130℃ with 2&24 hours anneal time

11. Concentrated solution (Sample 5 and 6), were Annealed at high temperature for 24hrs in the k+ form but not in the H+ form
Dilute solution (sample 22), annealed at a low temperature for 24hrs in the k+ form and also in the H+ form
Conductivity (S/cm) at 92%RH is stable, too high and has the world polymer membrane record

12. As the temperature increased, the conductivity and conductivity temperature increased

14. A concentrated solution annealed at a higher temperature and time is most preferable in a membrane of a PEM fuel cell application.
Using the SEM/EDX result, the more HPA in the membrane the better the proton conductivity
At higher temperature the molecules are moving faster for a better proton conductivity( increase in temperature increases conductivity).

15. Anneal films at 80℃ for 2hours
Try different annealing time between the range of hours in order to improve the performance of the membrane.
The use of methanol instead of Dmac and crosslinking for flexibility especially the concentrated solution.

16. Acknowledgement
We thank the Renewable Energy material Research science and Engineering center, Colorado fuel cell center and Colorado school of mines for support and assistance through out this project.
Special thanks to my Advisor, all the members of Dr. Herrings Lab and all those who have supported the research experience
Thanks to APS CUWiP for giving the opportunity and the sponsorship

17. Reference
Shin R. Mukai “immobilization of Heteropoly acid in the network structure of carbon gels” Applied Catalysis December (2003) : web