Water and ion transport in the cation exchange membrane systems NaClSrCl2 and KClSrCl2

Transient behavior of water transport in the membrane of a PEM fuel cell

“…Similarly, with contamination, the water transference coefficient is modified into [26,27,[31][32][33][34][35] …”

“…in which q a is the ionic fraction of Q nþ at the anode (0 < q a < 1) and q c is the ionic fraction of Q nþ at the cathode (0 < q c < 1), and X Q nþ X H þ are expressed by [26,27,35]…”

“…The contaminant may either exist in the membrane before use or enter into the membrane with the fuel due to the corrosion of piping or stack materials. In their series of studies, Okada and coworkers [28][29][30][31][32][33][34][35] found that for a Nafion R membrane, the attraction of some impurity ions is larger than that of the H þ cation, and the sequence is Fe 3þ >Ca 2þ >Ni 2þ >Cu 2þ >Na þ , which implies that an ion of higher valence has a greater attraction to the membrane. Since the conductivity of the membrane is linearly proportional to the number of H þ ions in the membrane, the conductivity of the membrane decreases as the number of impurity ions increases.…”

“…In their series of studies [24][25][26][27][28][29][30][31][32][33][34][35], Okada and coworkers investigated only the steady state water distributions in the membrane. In the application of a fuel cell for a dynamic system, such as a vehicular power system, the transient behavior of the fuel cell operation may be crucial, and this behavior has a close bearing on some of the characteristic times of the system, such as the time needed for water transport in the membrane to reach a steady state.…”

The Electrochemical Properties of Polysulfone Ion-Exchange Membranes

“…The K ion was found to have a higher mobility than that of the Na ion in a membrane with protons (36). The equilibrium data and the mobility data (37) indicate that K + moves more freely than Na + in a membrane with Ca 2+ .…”