PhD (M/F) Materials sciences - Li-ion Batteries - Electrochemistry - Solid-State Chemistry

Job Description

Thesis Subject

Title
New strategies based on insertion oxides for high-power Li-ion battery negative electrodes

Context and objectives
The rapid development of electric mobility and stationary energy storage requires lithium-ion batteries capable of sustaining very high charge/discharge rates while maintaining excellent lifetime performance and a high level of safety. Graphite-based negative electrodes, although industrially dominant, suffer from kinetic limitations and safety concerns related to lithium plating during fast charging. Niobium-based Wadsley–Roth structured oxides (WROs) are promising candidates due to their open crystallographic framework enabling fast lithium diffusion. However, these materials present two major drawbacks. First, long-term repetition of electrochemical processes may induce structural fatigue (local distortions, accumulation of mechanical stresses), progressively degrading capacity retention. Second, their instability below 1 V practically limits the accessible storage capacity, although their theoretical capacity is very high. This PhD project aims to go beyond conventional approaches based solely on chemical composition optimization of WROs by exploring new electrode strategies to simultaneously improve mechanical stability, energy density, and fast-charging performance.
Two original and complementary research directions will be investigated:
- Composite electrodes: the central hypothesis is that combining two electrochemically active materials operating alternately may provide a “mechanical relaxation window” for the WRO phase, by temporarily reducing its lithium insertion and therefore limiting accumulated stresses. Several insertion oxides will be considered, and optimizing the electrode formulation (mixing ratios, material morphology) will be crucial to maximize synergistic effects in terms of electrochemical performance.
- Thick electrodes: the objective is to produce highly densified self-standing electrodes using Spark Plasma Sintering (SPS) in order to increase volumetric energy density, while assessing the impact of electrode architecture (thickness, density, gradients) on ionic transport, polarization, and mechanical stability.

Methodology and working environment
The project will rely on close collaboration between ICGM and LRCS, within the French framework on electrochemical energy storage (RS2E). The PhD candidate will be enrolled in the Doctoral School of Balard Chemical Sciences, affiliated with the University of Montpellier. A large part of the work will be conducted at ICGM, and regular (potentially extended) research stays will be organized at LRCS depending on the project direction. Material synthesis and composite electrode formulation will mainly be performed at ICGM. The development of SPS protocols for thick electrodes will be carried out at LRCS. Electrochemical testing will be possible in both laboratories, including power capability tests, long-term cycling, and fast-charging protocols. A strong emphasis will be placed on operando X-ray diffraction, and synchrotron experiments may be performed, notably at ALBA (Spain).

Candidate profile
Applicants must hold a Master's degree (MSc) or equivalent in inorganic materials science, solid-state chemistry, or electrochemistry applied to batteries.

Expected skills
Strong interest in battery materials and structural characterization, experimental autonomy and scientific rigor, ability to work in a collaborative environment, and adaptability due to the two-site nature of the project.

Desired additional skills
Electrochemistry (cell assembly, electrochemical testing, electrochemical impedance spectroscopy, etc.), solid-state synthesis, X-ray diffraction / structural analysis, and data processing (Python, Matlab, etc.).

Your Work Environment

The project will rely on close collaboration between ICGM and LRCS, within the French framework on electrochemical energy storage (RS2E). The PhD candidate will be enrolled in the Doctoral School of Balard Chemical Sciences, affiliated with the University of Montpellier. A large part of the work will be conducted at ICGM, and regular (potentially extended) research stays will be organized at LRCS depending on the project direction. Material synthesis and composite electrode formulation will mainly be performed at ICGM. The development of SPS protocols for thick electrodes will be carried out at LRCS. Electrochemical testing will be possible in both laboratories, including power capability tests, long-term cycling, and fast-charging protocols. A strong emphasis will be placed on operando X-ray diffraction, and synchrotron experiments may be performed, notably at ALBA (Spain).

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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