Abstract
New ionomers based on perfluoro bis(sulfonyl)imides have been made by 3M and show promise for use in fuel cell membranes and electrodes. These ionomers have exceptionally high proton conductivity that can result in improved performance especially at low relative humidities. Fundamental to the success of these ionomers is oxidative stability in the fuel cell operating environment. Accelerated open circuit voltage (OCV) hold tests have been used to evaluate the durability and chemical stability of perfluoro bis(sulfonyl)imide ionomers in both membrane and electrode applications. A multi-layer membrane technique was employed to recover degraded samples for FTIR analysis and effluent water was collected and analyzed using LC-MS. These experiments show evidence that the carbon-sulfur bonds in the imide group are subject to the same cleavage mechanism proposed for the traditional perfluoro sulfonic acid (PFSA) ionomers.