Postdoctoral research engineer- Investigation of lithium-ion cells via electrochemical impedance spectroscopy and 3D numerical modeling M/F

Land

Frankreich

Ort

91 - Essonne

Ort des Arbeitsplatzes

PALAISEAU-ROUTE DE SACLAY(FRA)

Domain

Research Innovation&Developpt

Art des Auftrags

Unbefristeter Vertrag

Erfahrung

Mindestens 6 Jahre

Profil der Bewerberin/des Bewerbers

• Strong background in experimental chemistry-physics, preferentially in the field of electrochemistry, especially applied to lithium-ion batteries.
• Background in numerical modeling or a previous experience with numerical simulation would be greatly appreciated.

More information

• One-year postdoc position, starting date between June/September 2024.
• Located in the Institut de Chimie Moléculaire et des Matériaux d’Orsay (ICMMO), at Paris-Saclay University, Orsay, France.
• Salary is calculated from profile & experience. Up to 50 k€ gross/year.

Aktivitäten

The Institut de Chimie Moléculaire et des Matériaux d’Orsay (ICMMO) of Paris-Saclay University is looking for a one-year postdoc researcher to work on this project.

As a Postdoctoral Research Engineer specialized in your field, you are expected to:

• Conduct the following experimental work in first step:
• Fabricate LIB electrodes from graphite powder mixed with binder particles. For that purpose a classical liquid-media methodology will be used: powders mixing, ink preparation, coating/drying on metallic foil, calendering... Different electrode compositions, mass loadings, and thicknesses will be targeted.- Assemble the fabricated electrodes into symmetric cells, using different electrolytes.
• Carry out EIS experiments on the symmetric cells, and test the overall impedance at different temperatures.
• Finally, high-resolution 3D images of the graphite electrodes will be acquired using a FIB-SEM equipment.

You are also required to interpret EIS results as follows:

• At first, the EIS spectra (Nyquist plots) will be interpreted using classical techniques (i.e., electrical equivalent circuits), in terms of ionic and solid-phase resistances (including contact resistance at the collector interface), and pseudo-capacitance at the solid-electrolyte interface. Classical effects such as temperature and electrolyte concentration will be investigated first, for the purpose of validating the experimental methodology. Furthermore, the impact of electrode mass loading, thickness and composition will be quantified and analyzed. Particular attention will be paid to the tortuosity parameter.
• In a second step, a proprietary software tool from TotalEnergies will be used to construct a 3D numerical model of the symmetric cell and compute its impedance response. Numerical results will be compared to the EIS data, using an iterative procedure to adjust the uncertain model parameters (such as graphite surface coverage by binder), and performing a sensitivity study to verify their impact. The interpretation of the experimental results will be guided by their confrontation with simulation results, to better understand the impact of binder weight fraction, electrode porosity, and possibly additional microstructure parameters (e.g., particle size distribution), on the measured EIS spectra.

Kontext & Umgebung

Lithium-ion batteries (LIB) are the primary energy storage technology for modern portable electronic devices and for electric vehicles. They can also provide stationary storage for renewable energies and for grid frequency regulation. LIBs are likely to remain a dominant technology for the foreseeable future, with an enormous increase in demand. In this context, there is a strong incentive for battery manufacturers to accelerate the design of LIBs with enhanced performance, safety, and recyclability. R&D efforts are thus pursued in different areas, such as novel LIB materials and fabrication processes. The development of high-fidelity performance models is another important research field, with the potential to shorten and reduce the cost of LIB design cycles.

To address this challenge, TotalEnergies and its affiliate SAFT are investigating a novel multiscale strategy aiming to predict accurately the initial and ageing performances of LIBs under various utilization scenarios. This strategy relies on microscale continuum models, where LIB electrodes are represented by their 3D microstructures. It requires a large amount of experimental characterization for model construction and validation, involving various material property measurements, electrochemical analysis, high-resolution imaging (e.g., FIB-SEM and X-ray tomography), post-mortem studies, as well as in-operando investigations of battery cycling. Electrical impedance spectroscopy (EIS) is a classical approach for battery electrode characterization. Actually, EIS is one of the most practical in situ analysis techniques, which can discriminate electrochemical processes by their time constant. In that sense, EIS is particularly interesting since it is a non-destructive investigation method, giving access to several electrochemical parameters of major interest in the battery field (charge transfer, passivation film, adsorption, corrosion, ionic diffusion, tortuosity...).

TotalEnergies is a global multi-energy company engaged in the production and supply of various forms of energy: oil and biofuels, natural gas and green gases, renewables, and electricity. Its 105,000 employees are committed to providing increasingly affordable, clean, reliable, and accessible energy to a wide audience. Present in over 130 countries, TotalEnergies places sustainability at the core of its projects and operations to contribute to the well-being of communities.