Uniaxial stretching was used to promote desirable morphological changes to membranes composed of 3M Corporation's 825 equivalent weight (EW) perfluorosulfonic acid (PFSA) polymer. Stretching of solution cast PFSA films to a draw ratio of 4 was carried out prior to a high temperature annealing step. Film stretching increased the polymer crystallinity by 22% with an improvement in the membrane's mechanical properties. There was a small increase in proton conductivity after stretching, with a substantial decrease in methanol permeability. In direct methanol fuel cell tests at 60°C and 1.0 M methanol, the power density at 0.4 V with a stretched 3M 825 EW membrane was 72 mW/cm2, which was considerably greater that that obtained with a solution cast unstretched membrane (28 mW/cm2) or with a commercial Nafion 117 membrane (55 mW/cm2). ©The Electrochemical Society.
|Journal||E C S Transactions|
|Publication status||Published - 2010|
|Event||10th Polymer Electrolyte Fuel Cell Symposium; 218th ECS Meeting - Las Vegas, NV, United States|
Duration: 10 Oct 2010 → 15 Oct 2010
|Conference||10th Polymer Electrolyte Fuel Cell Symposium; 218th ECS Meeting|
|City||Las Vegas, NV|
|Period||10/10/2010 → 15/10/2010|