PhD (M/F) Materials Sciences – Solution Chemistry – Li-ion all-solid-state batteries - Electrolytes

Job Description

Thesis Subject

Thesis Subject
Title: Aqueous synthesis of new lithium oxythiobimetallates Li8-(n+m)M1n+1-yM2m+yS4-xOx (M1, M2 = P, Sb, Mo, W) - Towards sulfur-based ionic conductors, stable in humid conditions.

Context and objectives
Faced with the growing demand for energy, the development of mobile electricity, and the need to limit the consumption of fossil fuels, optimising the use of renewable energies and designing reliable and sustainable energy storage systems is obviousness. Currently, in terms of energy storage, lithium-ion battery technology covers most of the market needs (vehicles, mobiles, laptops, etc.). However, these storage systems require improvements such as increased safety and energy density. These aspects can be enhanced by replacing the liquid electrolyte with a solid component (1), making so-called “all-solid-state batteries” seen as the next-generation electrochemical energy storage technology. However, their development remains dependent on the design of solid ionic conductors with ionic conductivities of around 10-3 S/cm, which are close to those of liquid electrolytes (10-2 S/cm) (1).
Several families of solid electrolytes are being considered due to the difficulty of simultaneously meeting the required performance criteria (energy density, power, safety, interface stability, lifespan, cost, environmental impact, etc.) (2). Sulfur-based solid electrolytes are particularly interesting due to their superior ionic conductivity (10-3 S/cm) and their mechanical properties, which are suitable for cold assembly of the various components that make up the storage device (3). However, there are disadvantages, such as their low chemical stability with respect to humidity, which can lead to their degradation with the possible formation of toxic gases, such as hydrogen sulfide (H2S), and their reactivity with metallic lithium. In order to by-pass these drawbacks, a partial substitution of sulfur (S) with oxygen (O) is achieved. This aspect has been reported in the literature on thiophosphate electrolyte components such as Li3PS4 and Na3PS4 (5,6).
The topic of the thesis is to investigate and synthesis Li-based solid electrolytes such as Li-based thiometallates Li8-nMn+S4 (M = Sb, W, Mo) and oxithiometallates Li8-(n+m)M1n+M2m+S4-xOx (M1,M2 = P, Sb, W, Mo) in order to address the challenge of developing new lithium-ion-conducting phases that could represent promising solid electrolytes for all-solid-state batteries. The main objective will be preparing these phases using solution chemistry, which is a synthesis route that allows specific chemical compositions to be designed and the microstructure of the materials thus prepared to be controlled and adjusted. This method also offers mass production of the materials. Comprehensive physicochemical and electrochemical characterizations of all materials will be carried out to establish clear structure/property relationships for the developed compounds. In parallel, an investigation of electrode materials will also be conducted in order to design cells exhibiting interesting performance (interface compatibility, cycling, lifespan, etc.).

References
(1) Janek, J.; Zeier, W. G. A Solid Future for Battery Development. Nat. Energy 2016, 1 (9), 1–4.
(2) Manthiram, A.; Yu, X.; Wang, S. Lithium Battery Chemistries Enabled by Solid-State Electrolytes. Nat. Rev. Mater. 2017, 2 (4), 1–16.
(3) Wang, C.; Adair, K.; Sun, X. All-Solid-State Lithium Metal Batteries with Sulfide Electrolytes: Understanding Interfacial Ion and Electron Transport. Acc. Mater. Res. 2022, 3 (1), 21–32.
(4) Liu, Z.; Fu, W.; Payzant, E. A.; Yu, X.; Wu, Z.; Dudney, N. J.; Kiggans, J.; Hong, K.; Rondinone, A. J.; Liang, C. Anomalous High Ionic Conductivity of Nanoporous β-Li3PS4. J. Am. Chem. Soc. 2013, 135 (3), 975–978.
(5) Neveu, A.; Pelé, V.; Jordy, C.; Pralong, V. Exploration of Li–P–S–O Composition for Solid-State Electrolyte Materials Discovery. J. Power Sources 2020, 467, 228250.
(6) Kmiec, S.; Krupp, K.; Ruoff, E.; Manthiram, A. Effects of Oxide Precursors on the Structure and Properties of Na3PS4–xOx Glassy Solid Electrolytes. Chem. Mater. 2024.

Candidate profile
The candidate must have a MASTER 2 or Engineer degree in chemistry, electrochemistry or materials science.

Expected skills
Knowledge of energy storage and battery materials is required. We are looking for a serious and highly motivated candidate. The successful applicant should demonstrate the ability to work in a collaborative environment, as the project will be supervised jointly by two partners (Paris, Amiens).

Desired additional skills
An interest in solution chemistry and crystal chemistry will be advantageous. Prior experience in electrochemistry (e.g., battery assembly, cycling, impedance spectroscopy) or skills in NMR spectroscopy, and/or X-ray diffraction techniques would be a plus.

Your Work Environment

The Laboratoire de Réactivité et de Chimie des Solides (LRCS), a dynamic joint research unit between the CNRS and the Université de Picardie Jules Verne, is located in Amiens. More than 130 people of 25 different nationalities work mainly on electrochemical energy storage technologies (batteries), solar energy conversion (photovoltaics) and hydrogen storage.
The Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP) is recognized in the field of Material Sciences for the elaboration of functional inorganic and hybrid materials, and the evaluation of their physico-chemical properties at multiple scales. The lab brings together all facets of material chemistry with a strong coupling between synthesis methods and processing of materials. These materials target applications with a strong societal impact in the fields of energy, health, and environment.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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