Determining the Total Fluorine Emission Rate in Polymer Electrolyte Fuel Cell Effluent Water

Degradation of the polymer electrolyte membrane is still one of the major limiting factors, determining the lifetime of fuel cells. The chemical decomposition of the polymer electrolyte results in the release of HF, which can be quantified by the use of a fluoride ion selective electrode. However, polymer fragments can be released in significant quantities as well and thus the fluoride emission rate is an insufficient parameter to quantify electrolyte degradation. Therefore, a method to determine the total fluorine emission rate is developed. The thermal decomposition of the ionomer is made use of and by adding alkalis, released fluoride is captured.