Chemical and electrochemical oxidation of small organic molecules. - Page 186 |
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60
I “ ■
I
f 401
| 3 0 -
j 2 0 - s
I ,0.
20 30 40 SO 60 70 80 90
F m l Call Tamparatura (C)
Fig. 1.84 Methanol crossover current density of USC-MEA #2 as a function of
temperature under OCV conditions in a 1” x 1”-size direct methanol fuel cell.
An interesting feature of the methanol crossover characteristics across PSSA-PVDF
membranes is that the rates do not change substantially as a function of
current density, which is observed with systems employing Nafion® as the
electrolyte. This type of behavior is a general characteristic of low methanol
permeability membranes and represents an illustration of where the methanol
crossover effects of the system are dominated by diffusion of methanol in the
electrode structure.164
The methanol crossover rates were also measured for 3.0 M solutions in
operating fuel cells and compared with 1.0 M solutions under identical
conditions. It was observed that the methanol crossover rate was approximately
three times large for the 3.0 M solution when compared to the 1.0 M solution, as
illustrated in Fig. 1.85.
159
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
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| Title | Chemical and electrochemical oxidation of small organic molecules. - Page 186 |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 60 I “ ■ I f 401 | 3 0 - j 2 0 - s I ,0. 20 30 40 SO 60 70 80 90 F m l Call Tamparatura (C) Fig. 1.84 Methanol crossover current density of USC-MEA #2 as a function of temperature under OCV conditions in a 1” x 1”-size direct methanol fuel cell. An interesting feature of the methanol crossover characteristics across PSSA-PVDF membranes is that the rates do not change substantially as a function of current density, which is observed with systems employing Nafion® as the electrolyte. This type of behavior is a general characteristic of low methanol permeability membranes and represents an illustration of where the methanol crossover effects of the system are dominated by diffusion of methanol in the electrode structure.164 The methanol crossover rates were also measured for 3.0 M solutions in operating fuel cells and compared with 1.0 M solutions under identical conditions. It was observed that the methanol crossover rate was approximately three times large for the 3.0 M solution when compared to the 1.0 M solution, as illustrated in Fig. 1.85. 159 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. |
