초록 |
Since duPont showed that perfluorosulfonic acid ion-exchange membranes(Nafion®) have significant ionic conductivities and can be used in fuel cells. One important factor that can affect the performance of fuel cell is the methanol crossover of perfluorosulfonic acid membranes. A general thermodynamic model to describe phase equilibria for these systems is required. A Lattice-Fluid and Generalization Lattice-fluid model were applied to describe water activities of polymer electrolyte at the operation conditions of polymer electrolyte fuel cell(PEFC). The proposed models include the pressure contribution, the van der Waals energy contribution from dispersion, polar force and the specific energy contribution(GLF) from hydrogen bonding. We compared two models. Theoretical predictions and experimental results are in good agreement. However, considerations on pressure are predicted only theoretically. |