(Invited) Combining Constant Potential Molecular Dynamics and Experiments to Study Electrolyte Effects at Solid/Liquid Interfaces

Abstract

Liquid electrolytes are at the heart of many devices in energy storage and conversion applications. Bringing an atomistic picture of the composition-properties relation is essential to understand how their reactivity can be tuned, both in the bulk and at interfaces, by variation of their composition.In this talk, I will present some recent works where we elucidated the role of the electrolyte, by using state-of-the-art constant potential classical Molecular Dynamics [1] in combination with experiments. I will first introduce some developments that we did for treating metallic surfaces within the constant potential approach, which allows computing interfacial properties, e.g. capacitance, in good agreement with experiments.[2] Then, I will show a study about the insertion process of Li+ into LiFePO4 and K+ into Prussian blue for Li-ion and K-ion batteries, in aqueous vs non-aqueous electrolytes. I will describe the molecular aspects of the electrode-electrolyte interface that dictate ion transport and insertion processes, which strongly depend on the nature of the electrolyte.[3]I will finally illustrate some exciting perspectives for the design of more complex electrolytes, where water and an organic solvent are mixed, to control the reactivity of water at a solid/liquid interface. This finds direct applications in practical devices such as Li-ion batteries, multivalent batteries, or even electrolyzers. Our strategy was to confine the reactive species, i.e. water, in a non-reactive organic matrix and different salts. Modifying the nature of the salt as well as the salt/water ratio can be used to fine tune the water reactivity at the interface by controlling its coordination environment at both short- and long-range.[4,5] References [1] A. Marin-Laflèche et al., J. Open Source Softw., 5, 2373, 2020.[2] A. Serva, L. Scalfi, B. Rotenberg, M. Salanne, J. Chem. Phys., 155, 044703, 2021.[3] P. Lemaire, A. Serva et al., ACS Appl. Mater. Interfaces, 14, 20835, 2022.[4] N. Dubouis, A. Serva et al., Nat. Catal., 3, 656, 2020.[5] A. Serva, N. Dubuois, A. Grimaud, M. Salanne, Acc. Chem. Res., 54, 1034, 2021.