New Electrochemical Diagrams for Fuel Cells

For the PEMFC described by the half-reactions provided earlier, and considered at ambient conditions, the multiphase boundary electrochemical diagram can be presented as follows  

When temperature in the PEMFC is increased significantly above 100°C and H20(1) is transformed to HjOfg), the electrochemical diagram can reflect an important change at the cathode. The cathodic reaction still includes four species but becomes a three-phase electrochemical reaction  

In the electrochemical diagram above, the participants in the electrochemical reactions are clearly shown, while the phases are shown in the brackets immediately following the chemicals. The diagram also shows the intimate contact between the phases that must exist when the reaction occurs at each electrode. The conductive phases are all in contact, and the confnsion about what path the charge transfer flows across the phases is eliminated. 

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