Tuning Water Structure and Reactivity at Electrified Interfaces: Towards Nanostructured Aqueous Electrolytes by Professor Mathieu Salanne

07 Oct 2025 10.00 AM - 11.00 AM MSE Meeting Room (N4.1-01-28) Alumni, Current Students

NTU MSE Seminar Hosted by Professor Li Shuzhou

Abstract

Water, traditionally viewed as a passive solvent, is increasingly recognized as a dynamic reactant in electrochemical systems. The advent of "water-in-salt" electrolytes (WiSEs) and hybrid organic/water mixtures has revolutionized aqueous batteries, electrocatalysis, and electrosynthesis by expanding electrochemical windows, modulating reactivity, and enabling selective transformations. This seminar explores how the speciation, confinement, and nanostructuring of water in ionic and organic solvents can be harnessed to control its reactivity and selectivity at electrified interfaces.
I will first discuss the physicochemical properties of WiSEs, where water molecules are predominantly coordinated to cations, forming quasi-solvate ionic liquids and nanodomains. This unique environment alters water’s hydrogen-bonding network, in particular at the interface with the electrodes, which impacts strongly the electrochemical stability and enables high-voltage aqueous batteries [1,2]. Based on a similar idea, electrolytes were developed by confining water within organic matrices (e.g., acetonitrile, DMF, THF). This approach revealed how short- and long-range interactions—dictated by cation hydrophilicity, anion identity, and nanodomain formation—can fine-tune water’s electrochemical reactivity [3]. Recently, molecular dynamics (MD) simulations combined with small-angle X-ray scattering (SAXS) have demonstrated that the size and composition of aqueous nanodomains in hybrid electrolytes can be controlled by modulating the organic solvent [4,5]. The nanostructure directly impacts the reactivity of water for reactions such as electrocatalytic epoxidation.
[1] Bouchal et al., Angew. Chem., Int. Ed., 59, 15913-15917 (2020)
[2] Gomez Vazquez et al., J. Am. Chem. Soc., in press (2025)
[3] Dubouis et al., Nature Catalysis, 3, 656-663 (2020)
[4] Dorchies et al., J. Am. Chem. Soc., 144, 22734–22746 (2022)
[5] Dorchies et al., J. Am. Chem. Soc., 145, 17495–17507 (2024)

Biography


Professor Mathieu Salanne 
Sorbonne University (France)

Mathieu Salanne is professor of chemistry at Sorbonne University (France) and visiting professor at CNRS@CREATE (Singapore). His research field is the simulation of electrolytes for energy production and storage, with a focus on electrochemical interfaces. He obtained his PhD in 2006 and was appointed assistant professor at Sorbonne University in 2007 and promoted to full professor in 2016. He was group leader (ionic liquids and electrochemistry) at the PHENIX laboratory from 2014 to 2021, and was appointed as director of the Institute for computing and data science from 2022 to 2024. He also held am excellence chair in high-performance computing at Paris-Saclay University from 2014 to 2018. His research has been recognized by the IUPAP young scientist prize in computational physics in 2014, and he obtained an ERC consolidator grant in 2017 (AMPERE project). In 2020 he was appointed as a junior member of Institut Universitaire de France. He was member of the Editorial Advisory Board of the Journal of Chemical Physics (2020-2022), and currently serves as an Executive Editor for ACS Nano.

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