Modelling electrified electrolyte/electrode interfaces: from first-principles to machine learning, through hybrid QM/MM simulations

Abstract: 

Modelling the interfaces between electrolytes and electrodes has been traditionally a difficult problem. From the simple Helmholtz model for the double layer developed almost 150 years ago, the complexity of these interfaces has been incorporated in successive models. Currently, realistic simulations with atomic detail based on classical interatomic potential are feasible and relatively common. Nevertheless, first principles methods (such as DFT) have not been very useful in dealing with these systems, as the number of atoms and the time scales involved exceed the practical capabilities of these methods. Besides, dealing with electrified electrodes poses practical problems in DFT, adding complexity to the calculations. I will describe our recent work trying to overcome these difficulties and to address problems at the electrified interface from first principles, but also combining DFT calculations with more simplified models in the spirit of hybrid QM/MM calculations. I will also show some promising ideas of how to use Machine Learning methods to estimate directly the charge density in these interfaces, avoiding the expensive calculations involved in the DFT and QM/MM approach.

Short biography:

 Pablo Ordejón is Director of the Instituto Catalán de Nanociencia y Nanotecnología - ICN2 - in Barcelona. He obtained his PhD at the UAM in 1992, was a postdoc at the University of Illinois at Urbana Champaing (USA), and worked at the University of Oviedo and at ICMAB-CSIC. He works on the simulation of the properties of materials at the atomic level, using Density Functional Theory methods. He has developed numerical methods for very large scale simulations, with a focus on efficiency and reduced scaling with system size. He is one of the main co-developers of SIESTA, an open source DFT code for the study of complex materials, used by hundreds of groups worldwide. He is a Fellow of the APS, member of the Academia Europaea, and recipient of the Narcis Monturiol medal of the Government of Catalonia. He was co-founder of SIMUNE Atomistics, a spin-off company that provides materials simulations services to the industry.

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