I have already carried out polarization studies and electrochemical impedance measurements but the trends obtained from both techniques do not match. Could there be another method which could give more in depth information? It is helpful for my current studies on passive humidification methods for PEM fuel cell membranes.
I guess you did investigate MEAs with the named techniques, correct?
In order to evaluate degradation you could also include linear sweep and cycling voltammetry with your MEAs. CV gives you information on the electrochemically active surface area (catalyst). Hydrogen crossover and internal resistance can be determined from LSV. A reference electrode system will help to determine anode and cathode potentials separately. Current and temperature distribution in the cell can also be measured (see here: http://www.balticfuelcells.de/optequipE.html)
Another approach would be to do investigation on catalysts with RDE and RRDE. Half cell electrochemical investigation will also help.
Already mentioned has been SEM/TEM+EDX. We also use micro-CT in our labs.
There are even more techniques available - it depends on what you would like to find out.
Kind regards
Peter
Dear Peter and Fabrizio
Thank you so much for your inputs. I have also done CV for my studies but since the type of catalyst, loading and other parameters were kept constant, the ECSA for Pt did not vary significantly thus indicating similar activation losses in different systems. I am still betting on ohmic losses (membrane ionic resistance in particular) to give me more insight for my studies. Is there a way to measure ionic conductivity of membrane in situ/during test operations?
Regards
Dear Luca
Thank you so much for your comments. I understand that Ohmic resistance measured at the high frequency intercept is a combination of membrane resistance and internal resistance of cell components. So, is it right to derive ionic conductivity of membranes via this route considering tests carried out with different fuel cell setups?
regards
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