Quantum Mechanical Calculations of the Degradation in Perfluorinated Membranes Used in Fuel Cells

Proton exchange membrane fuel cells (PEMFCs) convert the energy of chemical reactions to electricity, with hydrogen as fuel and water as its main waste product. Currently the highly used Nafion membranes do not meet the 6,000 and 20,000 h operational requirement for cars and buses. In order to improve this characteristic, it is important to understand the mechanism responsible for membrane degradation in PEMFC. Based on the various scenarios studied, the most energetically favorable degradation mechanism in PEMFC occurs when H2 gas from the anode reacts with HO• from the cathode and generates H•. During concentrated HO• experiments such as Fenton or HOOH vapor test, the environment contains a high concentrations of hydroxyl radicals and water, but no O2 and H2 gas. Computational simulations are efficient tools for clarifying the Nafion degradation process, which were investigated using first principles quantum mechanics (QM) methods, density functional theory (DFT).