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October 2014 - present
January 2012 - September 2014
Education
November 2008 - December 2011
Publications
Publications (165)
This study investigates a salt design principle for aqueous battery electrolytes by combining chaotropic ions, guanidium cations (Gdm) and bis(trifluoromethanesulfonyl)imide anions (TFSI), forming GdmTFSI. This salt's crystal structure was solved via single-crystal X-ray diffraction and characterized using Fourier-transform infrared spectroscopy. S...
This study investigates a salt design principle for aqueous battery electrolytes by combining chaotropic ions, guanidium cations (Gdm) and bis(trifluoromethanesulfonyl)imide anions (TFSI), forming GdmTFSI. This salt's crystal structure was solved via single-crystal X-ray diffraction and characterized using Fourier-transform infrared spectroscopy. S...
Aqueous biphasic systems (ABSs) consist of two immiscible phases composed of only one solvent (water) with the phase separation driven by solutes such as polymers, ionic liquids and salts. Such two-phase systems have proved highly relevant in recent years for applications in electrochemical devices. Indeed, highly concentrated solutions of LiTFSI,...
Regardless of the promising performances of Proton Exchange Membrane Water Electrolyzers (PEMWE) for H 2 production, the high overpotential towards the oxygen evolution reaction (OER) (slow kinetic) still limits the large-scale use of such devices. 1,2
We have recently extended the aerosol synthesis route, a green, cheap and scalable synthesis tech...
Understanding (de)lithiation heterogeneities in battery materials is key to ensure optimal electrochemical performance. However, this remains challenging due to the three-dimensional morphology of electrode particles, the involvement of both solid- and liquid-phase reactants and a range of relevant timescales (seconds to hours). Here we overcome th...
The deployment of energy dense Ni-rich NMC (LiNixMnyCozO2 with x > 0.8) in Li-ion batteries is hampered by a poor interfacial stability above 4.2 V. Among the strategies to mitigate this instability, highly concentrated electrolytes (HCE) has shown a promising resilience at high potential. In this work, we demonstrate that although cells using HCE...
Electrosynthesis is a method of choice for designing new synthetic routes owing to its ability to selectively conduct reactions at controlled potentials, high functional group tolerance, mild conditions and sustainability when powered by renewables. When designing an electrosynthetic route, the selection of the electrolyte, which is composed of a s...
The electrification of our society requires safer and longer lasting batteries, for which modular electrolytes such as aqueous biphasic systems (ABS) are being developed. ABS, i.e. two-phase systems, were shown to enable high-potential dual-ion aqueous batteries based on Li-ion (de)intercalation at graphite negative electrode and halides (de)interc...
Aqueous batteries are regaining interest, thanks to the extended working stability voltage window in a highly concentrated electrolyte, namely the water-in-salt electrolyte. A solid-electrolyte interphase (SEI) forms on the negative electrode to prevent water access to the electrode surface. However, we further reported that the formed SEI layer wa...
Unlike the interface between two immiscible electrolyte solutions (ITIES) formed between water and polar solvents, molecular understanding of the liquid-liquid interface formed for aqueous biphasic systems (ABSs) is relatively limited and mostly relies on surface tension measurements and thermodynamic models. Here, high-resolution Raman imaging is...
The deployment of energy dense Ni-rich NMC (LiNixMnyCozO2 with x > 0.8) in Li-ion batteries is hampered by a poor interfacial stability above 4.2 V. Among the strategies to mitigate this instability, highly concentrated electrolytes (HCE) has shown a promising resilience at high potential. In this work, we demonstrate that although cells using HCE...
The hydrogen evolution reaction (HER) has been widely demonstrated to have a strong dependence on pH and on the source of protons, where a clear kinetic advantage arises in acidic conditions over near-neutral and alkaline conditions due to the switch in reactant from H3O+ to H2O. Playing on the acid/base chemistry of aqueous systems can avoid the k...
Correction for ‘The role of ion solvation in lithium mediated nitrogen reduction’ by O. Westhead et al. , J. Mater. Chem. A , 2023, https://doi.org/10.1039/D2TA07686A.
This study investigates a salt design principle for aqueous battery electrolytes by combining chaotropic ions, guanidium cations (Gdm) and bis(trifluoromethanesulfonyl)imide anions (TFSI), forming GdmTFSI. This salt's crystal structure was solved...
The electrocatalytic epoxidation of alkenes at heterogeneous catalysts using water as the sole oxygen source is a promising safe route toward the sustainable synthesis of epoxides, which are essential building blocks in organic chemistry. However, the physicochemical parameters governing the oxygen-atom transfer to the alkene and the impact of the...
Unlike the interface between two immiscible electrolyte solutions (ITIES) formed between water and polar solvents, molecular understanding of the liquid-liquid interface formed for aqueous biphasic systems (ABSs) is relatively limited and mostly relies on surface tension measurements and thermodynamic models. Here, high-resolution Raman imaging is...
Since its verification in 2019, there have been numerous high-profile papers reporting improved efficiency of lithium-mediated electrochemical nitrogen reduction to make ammonia. However, the literature lacks any coherent investigation systematically linking bulk electrolyte properties to electrochemical performance and Solid Electrolyte Interphase...
Transition metal oxides are state-of-the-art materials for catalysing the oxygen evolution reaction (OER), whose slow kinetics currently limit the efficiency of water electrolysis. However, microscale physicochemical heterogeneity between particles, dynamic reactions both in the bulk and at the surface, and an interplay between particle reactivity...
Transition metal oxides are state-of-the-art materials for catalysing the oxygen evolution reaction (OER), whose slow kinetics currently limit the efficiency of water electrolysis. However, microscale physicochemical heterogeneity between particles, dynamic reactions both in the bulk and at the surface, and an interplay between particle reactivity...
The electrocatalytic epoxidation of alkenes at heterogeneous catalysts using water as the sole oxygen source is a promising safe route toward the sustainable synthesis of epoxides, which are essential building blocks in organic chemistry. However, the physico-chemical parameters governing the oxygen-atom transfer to the alkene and the impact of the...
The lithium-mediated method of electrochemical nitrogen reduction, pioneered by Tsuneto et al ¹ then verified by Andersen et al ² , is currently the sole paradigm capable of unequivocal electrochemical ammonia synthesis. Such a system could allow the production of green, distributed ammonia for use as fertiliser or a carbon-free fuel. However, desp...
The electrocatalytic epoxidation of alkenes at heterogeneous catalysts using water as the sole oxygen source is a promising safe route toward the sustainable synthesis of epoxides, which are essential building blocks in organic chemistry. However, the physico-chemical parameters governing the oxygen-atom transfer to the alkene and the impact of the...
The hydrogen evolution reaction (HER) has been widely demonstrated to have a strong dependence on pH and on the source of protons, where a clear kinetic advantage arises in acidic conditions over near-neutral and alkaline conditions due to the switch in reactant from H3O+ to H2O. Playing on the acid/base chemistry of aqueous systems can avoid the k...
Since its verification in just 2019, there have been numerous high-profile papers reporting improved efficiency of the lithium-mediated electrochemical nitrogen reduction system to make ammonia. However, the literature lacks a cohesive investigation systematically linking bulk electrolyte properties to electrochemical performance and Solid Electrol...
Developing advanced electrolytes or electrode materials for Li-ion batteries heavily relies on the use of performance metrics, among which capacity retention and coulombic efficiency remains the gold standards. While powerful at predicting initial degradation rates, these metrics fall short to predict knee points that can abruptly lead to the sudde...
Water-in-salt electrolytes (WISEs) are prevailing thanks to their compelling extended voltage window due to the reduced free water molecules at the interface. However, free-water content can still be reduced. In our previous work, an unstable phenomenon of solid electrolyte interphase (SEI) and salt precipitation/dissolution issue were revealed. He...
The introduction of aqueous superconcentrated electrolyte, namely Water-in-salt electrolytes (WiSE), reinvigorated the field of aqueous electrolyte for Li-ion batteries (LIB). The electrochemical stability window of water-based electrolyte was shown to be expanded owing to the formation of a solid electrolyte interphase (SEI) at the negative electr...
The deployment of energy dense positive electrode materials such as Ni-rich NMC (LiNixMnyCozO2 with 0 < x, y, z < 1 and x + y + z = 1) for Li-Ion batteries is plagued by numerous interfacial limitations. Among them, dissolution of transition metals (TMs) was shown to trigger deleterious growth of solid electrolyte interphase (SEI) and/or lithium pl...
Understanding (de)lithiation heterogeneities in battery materials is key to ensuring optimal electrochemical performance and developing better energy storage devices. However, this remains challenging due to the complex three dimensional morphology of microscopic electrode particles, the involvement of both solid and liquid phase reactants, and ran...
Understanding the interfacial reactivity of aqueous electrolytes is crucial for their use in future batteries. We investigate the reactivity of the bis(trifluoromethane)sulfonimide anion when exposed to a strongly basic medium, by means of ab initio molecular dynamics and enhanced sampling techniques. In particular, we study the nucleophilic attack...
Battery 2030+ This Special Issue provides an overview of the scientific ambition for the European roadmap for future battery technologies “Battery 2030+”. It includes both the roadmap itself with its long term perspective as well as state of the art descriptions and deep‐dive articles outlining key themes of the roadmap. The overall purpose of “Bat...
The sodium‐air battery offers a sustainable, high‐energy alternative to lithium‐ion batteries. Discharge in the cell containing glyme‐based electrolytes can lead to formation of large cubic NaO 2 particles via a solution‐precipitation mechanism. While promising, high rates result in sudden death. The exact nature of the discharge product has been a...
Highly concentrated electrolytes offer enhanced energy-density for aqueous batteries, but the high salt concentration presents formidable challenges for practical implementation. Now, an electrolyte has been designed that has a substantially reduced salt concentration while still enabling high-performance batteries.
This roadmap presents the transformational research ideas proposed by “BATTERY 2030+,” the European large-scale research initiative for future battery chemistries. A “chemistry-neutral” roadmap to advance battery research, particularly at low technology readiness levels, is outlined, with a time horizon of more than ten years. The roadmap is center...
The verification of the lithium-mediated nitrogen reduction system in 2019 has led to an explosion in the literature focussing on improving the metrics of faradaic efficiency, stability, and activity. However, while the literature acknowledges the vast intrinsic overpotential for nitrogen reduction due to the reliance on in situ lithium plating, it...
Driven by the continuous search for improving performances, understanding the phenomena at the electrode/electrolyte interfaces has become an overriding factor for the success of sustainable and efficient battery technologies for mobile and stationary applications. Toward this goal, rapid advances have been made regarding simulations/modeling techn...
Li-ion batteries are the essential energy-storage building blocks of modern society. However, producing ultra-high electrochemical performance in safe and sustainable batteries for example, e-mobility, and portable and stationary applications, demands overcoming major technological challenges. Materials engineering and new chemistries are key aspec...
Understanding the interfacial reactivity of aqueous electrolytes is crucial for their use in future batteries. We investigate the reactivity of the bis(trifluoromethane)sulfonimide (TFSI) anion when exposed to a strong alkaline medium, by means of ab initio molecular dynamics and enhanced sampling techniques. In particular, we study the nucleophili...
The development of new batteries has historically been achieved through discovery and development cycles based on the intuition of the researcher, followed by experimental trial and error—often helped along by serendipitous breakthroughs. Meanwhile, it is evident that new strategies are needed to master the ever-growing complexity in the developmen...
Insertion compounds provide the fundamental basis of today’s commercialized Li-ion batteries. Throughout history, intense research has focused on the design of stellar electrodes mainly relying on layered oxides or sulfides, and leaving aside the corresponding halides because of solubility issues. This is no longer true. In this work, we show the f...
Today development of efficient catalytic systems for selective oxidation of alcohols to aldehydes remains not only a major concern in basic chemistry research but also a significant challenge for the chemical industry. One promising green and sustainable approach to increase the selectivity as well as waste reduction and to minimize the use of toxi...
This is a critical review of artificial intelligence/machine learning (AI/ML) methods applied to battery research. It aims at providing a comprehensive, authoritative, and critical, yet easily understandable, review of general interest to the battery community. It addresses the concepts, approaches, tools, outcomes, and challenges of using AI/ML as...
Open access to research data is increasingly important for accelerating research. Grant authorities therefore request detailed plans for how data is managed in the projects they finance. We have recently developed such a plan for the EU‐H2020 BIG‐MAP project – a cross‐disciplinary project targeting disruptive battery‐material discoveries. Essential...
Highly concentrated electrolytes were recently proposed to improve the performances of aqueous electrochemical systems by delaying the water splitting and increasing the operating voltage for battery applications. While advances were made regarding their implementation in practical devices, debate exists regarding the physical origin for the delaye...
Two-dimensional (2D) layered magnetic materials are generating a great amount of interest for the next generation of electronic devices thanks to their remarkable properties associated with spin dynamics. The recently discovered layered VI3 ferromagnetic phase belongs to this family, although a full understanding of its properties is limited by the...
Producing hydrogen by water electrolysis suffers from the kinetic barriers in the oxygen evolution reaction (OER) that limits the overall efficiency. With spin-dependent kinetics in OER, to manipulate the spin ordering of ferromagnetic OER catalysts (e.g., by magnetization) can reduce the kinetic barrier. However, most active OER catalysts are not...
Open access to research data is increasingly important for accelerating research. Grant authorities therefore request detailed plans for how data is managed in the projects they finance. We have recently developed such a plan for the EU-H2020 BIG-MAP project - a cross-disciplinary project targeting disruptive battery-material discoveries. Essential...
Highly concentrated electrolytes were recently proposed to improve the performances of aqueous electrochemical systems by delaying the water splitting and increasing the operating voltage for battery applications. While advances were made regarding their implementation in practical devices, debate exists regarding the physical origin for the delaye...
Scientific publications constitute the main information source of battery-related data for academic research. There is an impressive number of papers published on Lithium Ion Batteries (LIBs) for instance. Such impressive amount of data in principle could be used by machine learning (ML) methods in order to optimize efforts and even make possible t...
Two-dimensional (2D) layered magnetic materials are generating a great amount of interest for the next generation of electronic devices thanks to their remarkable properties associated to spin dynamics. The recently discovered layered VI$_3$ ferromagnetic phase belongs to this family, although a full understanding of its properties is limited by an...
Invited for this month's cover picture is an effort run by the group of Alejandro A. Franco and made in collaboration with Mathieu Morcrette, Patrik Johansson, Patrice Simon and Alexis Grimaud. The Front Cover illustrates an ideal scientific literature, in which all the data are systematically disclosed and available for researchers, together with...
The Front Cover illustrates an ideal scientific literature, in which all the data are systematically disclosed and available for researchers, together with artificial intelligence algorithms aiming to bring new light on the next generation of batteries. More information can be found in the Concept by A. A. Franco and co‐workers.
Insertion compounds provide the fundamental basis of today’s commercialized Li-ion batteries. Throughout history, intense research has focus on the design of stellar electrodes mainly relying on layered oxides or sulfides, and leaving aside the corresponding halides because of solubility issues. This is no longer true. In this work, we show for the...
The production of hydrogen by water electrolysis suffers from the kinetic barriers in the oxygen evolution reaction (OER) that limits the overall efficiency. As spin-dependent kinetics exist in OER, the spin alignment in active OER catalysts is critical for reducing the kinetic barriers in OER. It is effective to facilitate the spin polarization in...
p>Aqueous biphasic systems (ABS) can form when mixing water with two compounds such as polymers, ionic-liquids or simple salts. While this phenomenon has been known for decades and found applications in various fields such as biology, recycling or even more recently electrochemistry, the physics behind the formation of ABSs remains ill-understood....
In this study, the effect of flow of the electrolyte on an electrolysis cell and a zinc cell is investigated. The gain of energy brought by the flow is discussed and compared to the viscous losses in the cells. We point out that the balance between the gained electrical power and the viscous loss power is positive only if the hydrodynamic resistanc...
The recent discovery of “water-in-salt” electrolytes has spurred a rebirth of research on aqueous batteries. Most of the attention has been focused on the formulation of salts enabling the electrochemical window to be expanded as much as possible, well beyond the 1.23 V allowed by thermodynamics in water. This approach has led to critical successes...
Artificial Intelligence (AI) has the promise of providing a paradigm shift in battery R&D by significantly accelerating the discovery and optimization of materials, interfaces, phenomena, and processes. However, the efficiency of any AI approach ultimately relies on rapid access to high‐quality and interpretable large datasets. Scientific publicati...
CoCr2O4 activated at 1.7 V for 1.5 h (Act‐CoCr2O4) exhibits better OER activity compared to IrO2 in alkaline solutions. Pristine CoCr2O4 is originally inactive; activation (>1.56 V) promotes Cr leaching and lattice oxygen losses in CoCr2O4, leaving the highly defective surface for Co species to reconstruct into octahedrally coordinated Co3+–4+ oxyh...
A rational design on oxygen evolution reaction (OER) catalysts is pivotal to the overall efficiency of water electrolysis. Numerous works have been devoted to understanding the cation leaching and surface reconstruction of some very active electrocatalysts, while few have been on intentionally promoting the surface in a controlled fashion. In this...
In Science, Oener, Foster, and Boettcher demonstrate that combining acidic and basic oxides as water dissociation catalysts allows for reducing the overpotential induced by the use of bipolar membranes close to zero under practical conditions. Furthermore, they demonstrate that design principles are shared across water dissociation catalysts and wa...
Green hydrogen production using renewables-powered, low-temperature water electrolysers is crucial for rapidly decarbonizing the industrial sector and with it many chemical transformation processes. However, despite decades of research, advances at laboratory scale in terms of catalyst design and insights into underlying processes have not resulted...