Wet chemical synthesis of divided sulfides towards All solid state lithium batteries electrolytes

Nowadays, solid electrolytes are considered to be the key to the development of next generation batteries. Polymers and inorganics are two types of lithium conducting solid electrolytes which have been widely studied but their performances are still limited. A promising route to reach efficient electrolytes is to use inorganic nanoparticles.
Among the different inorganic materials available, the sulfur family (Li7P3S11, Li6PS5X with X= Cl, Br, I) exhibits high ionic conductivities. However, such materials are mostly obtained by solid state synthesis resulting in aggregated micrometric particles. Moreover, although some wet chemical synthesis were recently reported, the capability to control the size, the morphology and to prevent the aggregation has not been exploited yet.
The aim of this PhD project is to develop a synthesis method allowing the control of the particles size, morphology and aggregation to yield finely divided sulfur compounds. The idea is to adapt well-known oxide nanoparticles preparation methods to the wet chemical synthesis of sulfide phases. Various levers such as the reaction temperature, the nature of the solvent and the reagents as well as the addition of stabilizing agents will be explored. After physicochemical characterization, the ionic conductivity of the resulting sulfur particles will be measured and the most promising materials will be used to obtain electrolytes. The influence of the nanoparticles size and morphology will be studied. The best electrolytes will be tested in assembled coin cells.

Keywords: Wet chemical synthesis, solid electrolyte, sulfides, nanomaterials, lithium batteries

• Academic supervisor    Dr UZIO Denis, IFPEN
• Doctoral School    ED206, https://www.edchimie-lyon.fr/
• IFPEN supervisor    Dr GARNERO Cyril, cyril.garnero@ifpen.fr 
• PhD location    IFP Energies nouvelles, Lyon, France Pays 
• Duration and start date    3 years, starting December 2021
• Employer    IFP Energies nouvelles, Lyon, France
• Academic requirements    University Master degree: Materials Sciences, Chemistry
• Language requirements    Fluency in French or English, willingness to learn French
• Other requirements    Materials wet chemical synthesis, inert atmosphere handlings would be appreciated, knowledge in sulphur chemistry