Fuel Cells
Device that produces electricity from external
supplies of fuel and oxidant.
Types of Fuel cells
1) Proton Exchange membrane Fuel Cell
(PEMFC)
2) Direct Methanol
3) Solid oxide
4) Phosphoric acid
5) Alkaline
6) Molten carbonate
Proton Exchange membrane Fuel Cell (PEMFC)
Design & Operation:
Anode Reactions:2H2 => 4H+ + 4e-
Cathode Reactions:O2 + 4H+ + 4e- => 2 H2O
Overall Cell Reactions:2H2 + O2 => 2 H2O
Platinum: Anode & Cathode
Operating temperature: about 80 0C
Membrane: Nafion,
Polybenzimidazole (PBI)
Why PEMFC?
1) Higher power density (About 10 times greater than other fuel cells)
2) Lower cost
3) Instant startup
4) It is tiny, so easy to handle
5) Solid polymer membrane allows low pressure fuel & high pressure air on other side
6) Operates on pure hydrogen as well as reformed hydrocarbon fuels.
Few drawbacks:
1) Platinum anode gets poisoned by CO in fuel
2) Operates at temp. < 100 0C
3) Water management issues
4) Water & air crossover to anode through membrane
5) Less proton mobility through membrane
Future work
Study of polymer membranes and issues related to PEMFC