Researcher: Design- development of high power, high energy Na-ion batteries through interphase engineering (M/F)

Li-ion batteries (LIBs), one of the major advancement in the history of technology, has reached its current state of maturation solely after tuning the electrode- electrolyte interface, which is most important in governing the life and safety of a battery and least understood yet within the field. A similar thrive is essential for sodium ion batteries (NIBs), which are currently on endeavor to take a share from LIB market, due to their low cost, sustainability and almost same engineering that can be used for both LIB and NIB assemblies. Significant achievements were made and the Na-ion cells based on polyanionic Na3V2(PO4)2F3- hard carbon chemistry are under commercialization thanks to the interphase engineering by electrolyte optimization. Now, the next step is to move for cheaper and high energy electrode materials without compromising the power capabilities. In such case, more deep understanding on the materials level as well interface is required as the conductivity in the bulk electrolyte, interphase as well as Na-ion diffusion in the electrode plays a huge role in deciding the power rate capability as well as the cell life. This is what the researcher will explore by modifying the positive/ negative electrode and studying the interface chemistry by operando and ex-situ techniques.

The study will focus on high energy electrode materials together with different electrolyte formulations based on new additives and co-solvents as well as new chemistries such as highly concentrated electrolyte and locally concentrated electrolytes. The interface chemistry and its stability will be followed by RRDE, cyclic voltammetry (both on oxidation, reduction), galvanostatic cycling and change in resistance upon cycling. Pressure changes and gaseous product evolutions during interface formation and upon cycling will be followed by pressure analyses and mass spectrometry.

Majority of the work will be carried out in Chimie du solide et énergie at Collège de France, Paris. Few travels to other laboratories in RS2E network is expected based on the requirement.