Physchem.cz

Electrolytes and interphases in Post Li batteries

Large research efforts are devoted to the Li-ion battery technology, which is now mature and plays a major role in the field of portable electronics and electromobility. Aside from controversial debates on lithium and other critical raw materials supply, the development of new battery chemistries is appealing, especially in large scale stationary applications for which cost is a critical aspect. Interesting alternatives are to use sodium, calcium or magnesium instead of lithium. Current efforts on these alternative technologies are mostly devoted to the search of new electrode materials, while studies dealing with the electrolyte are much scarcer.

Electrolytes (combination of salt, solvent and additives) play a crucial role in the battery performances. Among other important requirements, the electrolyte must ensure fast mobility of electroactive species (cations) from one electrode to the other, it must wet properly the separators and the electrodes, it should remain stable in contact with fully charged electrodes (large electrochemical stability window) or lead to the formation of stable interphase preventing continuous electrolyte decomposition.

In this seminar, I will introduce the main selection criteria for electrolyte components and show comparative studies of various post-Li electrolyte formulations and their physico-chemical properties (viscosity, ionic conductivity, electrochemical and thermal stabilities). Results will be discussed together with cation solvation trends and investigations on the electrode/electrolyte interface and its impact on the performance of Na, Ca and Mg based cells. Finally, the reliability of electrochemical setups to test new electrode and electrolytes for post-Li battery will also be discussed.