PAFC Basic Principles and Operations

The PAFC works in a similar fashion to the PEMFC described in Section 9.2. The electrolyte is an inorganic acid concentrated phosphoric acid (100%), which, like the membranes in the PEM cells, will conduct protons and the reactions occurring on the anode and cathode, is similar to the PEFC. At the 

In the PAFC, the electrochemical reactions take place on highly dispersed electrocatalyst particles supported on carbon black. As with the PEMFCs, platinum (Pt) or Pt alloys are used as the catalyst at both electrodes. The PAFC operates at an elevated temperature compared to the PEFC, at 160°C-220°C. The higher-temperature PAFC was chosen for development for terrestrial applications. Since the PAFC has a range of operating temperature (16°C-220°C), operating pressure ranges from 1 atm to several atmospheres. Typical current densities are 150-350 mA/cm with output voltage per cell of 0.5 to 0.8 V. The reactant flow stoichiometries are similar to other fuel cells. 

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