Lithium batteries are in full development for the electric vehicle and portable application and the CEA has just launched a vast research program with a large car manufacturer. These batteries are made up of two positive and negative electrodes and an electrolyte. The electrolyte is currently a mixture of lithium salt, of ethylene carbonate and a co-solvent to decrease the viscosity of the mixture and thus to ensure a good ionic conductivity. For stability and safety reasons, it is interesting to replace these solvents by ionic liquids which present a strong electrochemical stability and a negligible vapour tension.

The understanding of the ionic conductivity in these electrolytes is closely related to the diversity of the dissolved species and the complexity of the elementary transport mechanisms. It thus appears crucial to understand the transport mechanisms as well as the rheological properties of these new systems by taking into account the individual behaviour of the various components of these electrolytes (cation, anion, solvent) as well as their respective interactions. It thus appears crucial to understand the mechanisms of transport as well as the rheological properties of these new systems in the range of temperature under consideration for application.

This subject is predominantly experimental. This study will enable the candidate to tackle a promising subject and to acquire tranverse competences . This work will enable to run experiment in large facilities (ESRF/ILL/LLB).