Improvement of polymer electrolyte membranes for polymer electrolyte membrane and direct methanol fuel cell applications

The polymer electrolyte membrane is one of the major components of polymer electrolyte membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). To improve the properties of polymer electrolyte membranes (PEMs), studies were carried out in three areas: (a) oxidative thermal stressing experiments of Nafion(R) membranes, (b) thermal gravimetric analysis (TGA) of three different types of PEMs under both nitrogen and oxygen purges and (c) attempted minimization of methanol crossover via doping of Nafion(R) membranes with bulky cations such as trimethylammonium, tetramethylammonium, and trifluoroethyl(trimethyl)ammonium. These studies were aided by the use of TGA, X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and gas chromatography/mass spectrometry (GC/MS).