Date: 06 September 2023
Time: 12.45 Hours
Room: RA1501 & online
Speaker: Prof.dr. Alexey V. Lyulin (DAMUT -3MS - Multiscale Molecular Dynamics (MMD) & TU/e - SMB)
Title: “Multiscale modelling of perspective polyelectrolyte membranes for flow and fuel batteries"
Abstract:
Polyelectrolyte membranes (PEMs) are key components to be used in fuel cells and flow batteries [1-3]. Nafion is a widely used membrane for both flow batteries and PEM fuels cells (PEMFCs). It has good conductivity and mechanical stability at room temperature, but due to the loss of water upon heating, the conductivity of Nafion degrades. We discuss and compare the characteristics of Nafion and some multi-acid side-chain PEMs as PFIA. The recent experiments show significant conductivity decrease upon annealing [4]. In this paper, we discuss the results of our recent fully atomistic classical molecular-dynamics simulations of hydrated Nafion at various hydration levels and annealing rates. Our simulations show the compression of hydrophobic Nafion domains by larger water clusters, with a strong antiplasticization effect upon hydration, demonstrated by the increase of the glass-transition temperature. The water clusters in hydrated Nafion become more disconnected and larger in size with slower cooling rates/increased annealing time. This results in the decrease of water and hydronium diffusivity and the corresponding conductivity, thereby explaining qualitatively the experimental observations.
REFERENCES
[1]. S. Sengupta, R. Pant, P. Komarov, A. Venkatnathan, A.V. Lyulin, Int. J. Hydrogen Energy, 42, 27254-27268, 2017.
[2]. S. Sengupta and A. V. Lyulin, J. Phys. Chem. B, 122, 6107-6119, 2018.
[3]. S. Sengupta, A.V. Lyulin, G. Kritikos, K. Karatasos, A. Venkatnathan, R. Pant, P. Komarov, in “Theory and Modelling of Polymer Nanocomposites, V. Ginzburg, L. Hall, Eds, Chapter 6, Springer series in Mater. Sci., 2021.
[4]. A. V. Lyulin S. Sengupta, A. Varghese, P. Komarov and A. Venkatnathan, , ACS Appl. Polym. Mater., 2, 5058-5066, 2020.