Atomistic simulation of proton transfer ability of Isopoly acid (IPA)/Heteropoly acid (HPA) doped Nafion® 117 for high-temperature fuel cell applications. (15th March 2019) - Akbari, Saeed
Abstract: Polyoxometalate (POM) doped perfluorosulfonic acid (PFSA) membranes are well-investigated electrolytes for high-temperature fuel cell applications. In the present study, classical and quantum molecular dynamics simulation were used to investigate the morphological features and proton transport properties of isopoly acid (IPA)/heteropoly acid (HPA) doped Nafion ® 117. This represents the first application of Anderson-type POM as dopant. The composite membrane matrix contains H3 PW12 O40, H5 IW6 O24, H9 AlW6 O24, and H2 W6 O19 . An anion interaction with the side chain increases its phase segregation. Quantum calculation results show that lifetime and half-life of hydrogen bonds (H-bond) decreases in the order: Nafion ® 117 < IPA doped Nafion ® 117 < HPA doped Nafion ® 117. In the HPA doped Nafion ® 117 matrix, proton can hop faster between H2 O molecules than IPA doped one. The membrane containing Anderson-type HPA with Al as heteroatom shows the least activation energy barrier for proton hopping. Besides, the self-diffusion coefficients of H2 O and H3 O + of composite membrane were also calculated.