Zeolite/ionic liquid composites as semi-solid electrolytes for Li or Na ion batteries

IFP Energies nouvelles (IFPEN) est un acteur majeur de la recherche et de la formation dans les domaines de l’énergie, du transport et de l’environnement. De la recherche à l’industrie, l’innovation technologique est au cœur de son action, articulée autour de quatre priorités stratégiques : Mobilité Durable, Energies Nouvelles, Climat / Environnement / Economie circulaire et Hydrocarbures Responsables.

Dans le cadre de la mission d’intérêt général confiée par les pouvoirs publics, IFPEN concentre ses efforts sur :

l’apport de solutions aux défis sociétaux de l’énergie et du climat, en favorisant la transition vers une mobilité durable et l’émergence d’un mix énergétique plus diversifié ;
la création de richesse et d’emplois, en soutenant l’activité économique française et européenne et la compétitivité des filières industrielles associées.

Partie intégrante d’IFPEN, l’école d’ingénieurs IFP School prépare les générations futures à relever ces défis.

Zeolite/ionic liquid composites as semi-solid electrolytes for Li or Na ion batteries

In Gen4 Li-batteries, liquid electrolytes (which cause safety hazards due to their flammability and volatility) will be replaced by solid state electrolytes. Current state-of-the-art solid electrolytes are based on thiophosphates, but they suffer from low chemical stability and are also not truly safe (their decomposition can produce H₂S). Oxides would be a lot more stable also having a high ionic conductivity, but they suffer form different challenges, including brittleness, interfacial compatibility issues with electrodes, and manufacturing difficulties.

Achieving a dense oxide phase indeed requires high-pressure and high-temperature sintering, which poses concerns for scalability. Therefore, semi-solid electrolytes have been explored, i.e. mixtures of polymers with ionic liquids.

The shortcoming of these systems is the low contribution of Li⁺ to the overall ionic conduction (low Li transference number). To remediate this, the proposed project aims to develop ionic-liquid-based electrolytes but immobilizing the anion of the ionic liquid, by encapsulation in a porous host material. Zeolites are very attractive candidate for this purpose, since their extraframework cations can contribute to the ionic conduction.

The master project will explore the potential of zeolite/ionic liquid composites as single-ion Li (or Na) conductors and study the transport mechanisms in these systems.

DESCRIPTION

The project tasks include the preparation of the composite materials, their physico-chemical characterization (XRD, TGA, NMR, etc.) and the evaluation of their electrochemical behavior (ionic conductivity, electrochemical stability window).

Specific experimentation will be designed to study the transport behavior in these systems, in order to evaluate the contribution of the two components, zeolite and ionic liquid, to the overall conductivity.