All-solid-state Li-ion batteries: advanced characterization to unravel solid electrolyte/cathode interfaces

In the ever-growing context of electrification in the automotive sector, the lithium-ion battery is currently the market’s dominant technology. Nevertheless, the energy density of current batteries, and therefore the range of electric vehicles, remains low compared to that of internal combustion vehicles. The risks associated with the thermal runaway of batteries also pose a barrier to their use in electric vehicles.
IFPEN is currently conducting research in the field of solid electrolytes, particularly polymer-based ones, to increase the energy density and safety of Li-ion batteries. However, the solid electrolytes developed today, whether organic, inorganic, or composite-based, are incompatible with “high-potential” cathode materials. This incompatibility appears to be linked, among other factors, to degradation phenomena occurring at the interface between the two materials. Despite numerous studies on the subject, these phenomena, which are responsible for performance degradation, are still poorly understood.
The first objective of the PhD will be to determine the relevant characterization methods to gather information at the interfaces (electron microscopies; infrared, photoemission, X-rays absorption spectroscopies…). It will also be necessary to develop appropriate sample preparation methods to access the interfaces while ensuring their integrity. In a second phase, cells with different types of solid electrolytes will be fabricated and subjected to cycling and electrochemical tests to highlight performance degradation. Finally, the interfaces created in each configuration will be characterized using the developed protocols. The ultimate goal of this multidisciplinary PhD is to achieve a comprehensive description of the degradation mechanisms at the interfaces and propose remediation solutions.

Keywords: Li-ion batteries, electrochemistry, materials characterization, electron microscopies 

• Academic supervisor    Dr Virgile ROUCHON, IFPEN, ORCID : https://orcid.org/0000-0001-8520-1378
• Doctoral School    ED034 EDML, Université Lyon 1, Claude Bernard
• IFPEN supervisor    Dr Julie POULIZAC, ORCID : https://orcid.org/0000-0003-4229-2841
• PhD location    IFPEN, Lyon, France
• Duration and start date    3 years, starting in the fourth quarter 2026 (Novembre 2)
• Employer    IFPEN
• Academic requirements    University Master degree in Chemistry, Analytical Chemistry, Material Science, Electrochemistry   
• Language requirements    English level B2 (CEFR), French level A2 (CECR)    
• Other requirements    Electrochemistry, materials chemistry, basic knowledge in materials characterization would be appreciated, 

To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.