The escalating climate crisis and limited supply of fossil fuels have made it imperative that alternative energy technologies be developed. In particular, by replacing combustion engines and powering personal electronic devices, anion exchange membrane (AEM) fuel cells could be an important component of a long-term, clean energy strategy. Molecular dynamics simulations can provide important atomic resolution details about the structure and dynamics of these systems to aid in developing, characterizing, and optimizing these materials. The work presented will feature two major components: the development of methodologies to increase the efficiency and accuracy of simulations of these systems, and the application of computational methods to systems related to the development of fuel cell membranes. AEMs enable the transport of hydroxide from the cathode to the anode, which involves bond breaking and forming events. Classical interaction models are not equipped to deal with reactions, so it was necessary to develop a reactive model of hydroxide. Also an approach that dramatically increases the efficiency of free energy calculations by optimizing the protocol used to connect two states of interest will be presented. These methods are paired with molecular dynamics simulations to describe the effects of concentration and counterions on anion transport in aqueous solutions of hydroxide salts and alkylammonium salts. Last, the solvation structure and dynamics of hydroxide are characterized in AEMs with the aim of connecting membrane composition and characteristics to the desired hydroxide transport properties. The results from these atomistic simulations will be coupled with macroscopic observables from experiment to characterize the performance of AEMs and suggest possible improvements to advance fuel cell technologies.

Guiding the development of anion exchange membrane fuel cells with molecular dynamics simulations

246th National Meeting (2013)

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