Scientific Events

Electrochemical energy storage is the key enabling component of electric vehicles and solar/wind-based energy technologies. The enhancement of energy stored requires the detailed understanding of ionic transport and electrochemical and electromechanical phenomena on local scales which are not always accessible with classical electrochemical techniques, such as voltammetry. Therefore, local probing of electrochemical and electromechanical behaviors on individual structural elements and heterogeneities, from grains to defects and further to individual atomic and molecular species, are invaluable. In this talk, I want to introduce force-based atomic force microscopies (AFM) to provided novel insights into local electrochemical processes on tens of nanometer and even molecular length under electrochemical control. I will highlight the development and application of in situ/operando force-based AFM methods to gain insight into the local charge storage mechanism in a variety of energy related materials. In the first part of the talk, I will showcase how AFM can be used to investigate the structure and dynamics of the electric double layer (EDL) for electrochemical capacitors. I want to highlight work on room temperature ionic liquids on model graphene electrodes since ionic liquids hold the promise of increasing the electrochemical stability windows for electrochemical capacitors. AFM was used to observe topological defects and show the existence of structural domains parallel to the solid-liquid interface towards a full picture of the double layer structure and their change with applied bias. In the second part of the talk, I want to highlight how AFM-based methods can be used to study ionic transport and local electrochemical reactions in supercapacitors and battery materials. Here, electro-chemo-mechanical coupling is the key to study ion insertion pathways and heterogeneities in local redox reactions. The first is demonstrated for the cation insertion into layered Ti3C2 electrodes based on their change in mechanical stiffness whereas the second is highlighted for proton insertion into WO3 where the relationship between electrochemical current and electrode strain are discussed. [more]

The advent of solid-state batteries has spawned a recent increase in interest in lithium conducting solid electrolytes. However, many open questions remain when trying to optimize electrolytes and understand solid state battery chemistries. In this presentation, we will show how an understanding of the structure-transport properties can help tailor the ionic conductivity. In an exemplary study on superionic lithium metal halides, we show that a cation site-disorder and the local structure of materials is important to study, especially as synthetic influences control materials properties. In a second part of this presentation, we will show the tremendous influence of lattice dynamics on ionic conductors. By introducing a different approach to understanding ionic motion using phonon occupations, we try to explain so far unexplained behaviors of physical ionic transport. Finally, we will show that it is not only important to find fast ionic conductors, but that fast ionic conduction is paramount within solid state battery composites. Measuring the effective ionic transport in cathode composites provides an avenue to explore transport and stability limitations that in turn provide better criteria for solid state battery performance Bio: Wolfgang Zeier received his doctorate in Inorganic Chemistry in 2013 from the University of Mainz. After postdoctoral stays at the University of Southern California, the California Institute of Technology, and Northwestern University, he was appointed group leader at the University of Giessen, within the framework of an Emmy-Noether research group. Since 2020 he holds a professorship for Inorganic Chemistry at the University of Münster. In addition, he heads a department at the Helmholtz-Institute Münster, Ionics in Energy Storage. His research interests encompass the fundamental structure-to-property relationships in solids, with a focus on thermoelectric and ion-conducting materials, as well as solid-solid interfacial chemistry for all-solid-state batteries. [more]

In order to address climate change, we must transition to a low-carbon economy. Many clean primary energy sources, such as solar panels and wind turbines, are being deployed and promise an abundant supply of clean electricity in the near future. The key question becomes how to store, transport and trade this clean energy in a manner that is as convenient as fossil fuels. The Alternative Fuels Laboratory (AFL) at McGill University is actively researching the use of recyclable metal fuels as a key enabling technology for a low-carbon society. Metal fuels, reduced using clean primary energy, have the highest energy density of any chemical fuel and are stable solids, simplifying trade and transport. The chemical energy stored in the metal fuels can be converted to useful thermal or motive power through two main routes: the Dry Cycle, where metal powders/sprays are burned with air, or the Wet Cycle, where metal powders are reacted with water to produce hydrogen and heat as an intermediate step before using the hydrogen as a fuel for various power systems. This talk will overview the concept of metal fuels and the various power system options. It will also touch on the combustion and reaction physics of metal fuels and the propagation of metal flames. Bio: Jeffrey Bergthorson is the Panda Faculty Scholar in Sustainable Engineering and Design, and a Professor in the Department of Mechanical Engineering, at McGill University where he leads the Alternative Fuels Laboratory. He received his B.Sc. in Mechanical Engineering from the University of Manitoba (1999), and his M.Sc. (2000) and Ph.D. (2005) in Aeronautics from the Graduate Aeronautical Laboratories of the California Institute of Technology. Prof. Bergthorson is a Fellow of the Combustion Institute and a Fellow of the American Society of Mechanical Engineers. Prof. Bergthorson’s research interests are in the broad area of the combustion and emissions properties of alternative and sustainable fuels, including biofuels, hydrogen, and the use of metals as recyclable fuels. [more]

In 2020, every major company’s annual report contained the word digitalization, A.I. or industry 4.0. It is easy to perceive these as buzzwords, aimed at investors, but the reality is more complex: companies are expected to transform now, driven by the fear of becoming obsolete. As researchers, this exciting transition creates significant opportunities: huge amounts of data are becoming readily available, while computing power and machine learning (ML) algorithms are more accessible than ever. However, this is also leading to disproportionate hopes and expectations regarding the actual capabilities of such methods, that only a working knowledge of ML combined with technical expertise in your field can rationalize. As R&D engineers, this critical view will be expected from you. Since technical expertise has already been the focus of your professional career, the effort should therefore be put on acquiring a practical knowledge of ML, that is, what problems can be solved and how to solve them? In this talk, some applications of ML to solve industrial issues (predictive modeling, visualization, combination with physical models...) will be discussed. Furthermore, practical aspects, such as data preparation, models implementation and maintenance will be reviewed, with the aim of providing actual insights on the root causes of successes and failures of ML applied to the steelmaking process. [more]

Besides their ubiquitous use in load-bearing structures, metals also possess qualities of energetic materials. Lithium, for example, is a common fuel in batteries, while aluminum is frequently added to solid rocket propellants and used in pyrotechnics. At high temperatures, metal powders can be burned in air in a similar way to hydrocarbon fuels, releasing chemically stored energy as sensible heat. Contrary to hydrocarbon combustion, however, the main reaction products are solid oxide particles that can, in principle, be retrieved from the exhaust fumes. This amenability to oxide sequestration has stimulated the idea of harnessing metal powders as recyclable energy carriers which are burned, retrieved and, subsequently, recharged by a reduction process based on clean primary energy. Conceptually, the metal powders are akin to high-temperature batteries, serving as a means to buffer the large spatial and temporal intermittency associated with renewable energy sources. Motivated by the potential use of metal powders as recyclable fuels, we qualitatively discuss the physical and chemical processes involved in the combustion of a single metal particle and of metal dusts, respectively. Subsequently, a population balance model for predicting the size distribution of the oxide smoke precipitating in the vicinity of a single burning aluminum particle is presented. Here, we specifically focus on the kinetic rates that control the phase transitions and smoke dynamics, integrating recently developed detailed kinetics for gas phase and heterogeneous surface reactions. The population balance equation governing the oxide size distribution is solved with the aid of a tailored adaptive grid method. An alternative, potentially more economical solution approach we propose is based on an embedded reduced order representation of the particle size distribution that is informed by a training step. The accuracy and convergence properties of this method are investigated for a simplified test case involving particle growth and dispersion in a laminar plane jet. In the final part of the seminar, the physical description, from an Eulerian viewpoint, of metal powders is discussed with a particular emphasis on the ramifications of carrier flow turbulence. In order to account for the small-scale interactions between dispersed particles and the ambient gas phase, the population balance equation governing the metal powder or oxide smoke is integrated into a probabilistic description that naturally accounts for the variability among independent realizations of a turbulent, particle-laden flow. Owing to the high dimensionality of the resulting transport equations, a stochastic solution approach based on Eulerian stochastic fields is proposed for which we show preliminary accuracy and convergence analyses.

The extraction and processing of resources are directly linked to 50% of all human-induced climate impacts and 90% of biodiversity losses (Bruno Oberle et al., 2019). Promoting resource efficiency is therefore recognised worldwide as a solution approach to counteract this rapid development. The circular economy (CE) approach brings new dynamism to the discussion of the well-known concept of resource efficiency (van Ewijk, 2018; Weizsäcker et al., 1997). Both approaches aim to reduce resource use and thus prevent tremendous environmental impacts. For example, the CE is thought to be crucial for reaching climate neutrality by 2050 as well as decoupling of economic growth and resource use (European Commission, 2020). Studies estimate that eco-design, waste prevention and reuse may result in up to EUR 600 billions of savings for businesses in Europe (Kalmykova et al., 2018). The metal industry is of high importance in this discussion as metal production is responsible for 8% of the global energy expenditure (UNEP 2013). Steel production alone is responsible for a quarter of all industrial GHG emissions (Allwood et al., 2011; Ito et al., 2020). However, the metal industry and especially the steel industry can look back on a long history of recycling as a core principle of the CE resulting in great resource savings. Nevertheless, there are major doubts as to whether future steel production can be covered entirely by secondary material. This is due to the dependency of the recycling infrastructure on primary metallurgy, the limits of recycling and the low degree of circularity of steel (Haas et al., 2015; Pauliuk, Wang, et al., 2013; Steger et al., 2018; Xylia et al., 2018). In the presentation, the challenges of resource use in general as well as the possible strategies of the Circular Economy are presented and their applicability for the field of metals, in particular steel, is discussed. To illustrate this, project examples will be presented in which, on the one hand, the CE strategies of re-purposing/re-manufacturing and, on the other hand, a technical approach of sorting by specific type for recyling will be illustrated. [more]

Natural materials are multifunctional. Consider the simple shell of a gastropod: it evolved to achieve balance during locomotion, protection against predation and dehydration, storage of mineral, anchoring structure for muscles… And what is fascinating is that all this is realised using 95% of calcium carbonate. As a comparison, the engineered equivalent of a mollusc shell would be chalk, a material with very low functionalities… The key difference between natural and most engineered materials is the intricate microstructures in which the building blocks (calcium carbonate in our example) are arranged. Developing the tools to translate these microstructures into engineered materials would allow us to better understand microstructure-properties relationships. Ultimately, this could create new sets of materials with unique combinations of properties.In this seminar, I will present the latest progress from our group on the fabrication of bioinspired microstructures for engineering and discuss the potential of those materials. [more]