The proposed thesis aims at securing the innovation in the development of new generations of Na-ion battery technologies in the quest of optimized overall performances of this promising battery technology (see eg. N. Tapia-Ruiz et al paper_https://doi.org/10.1088/2515-7655/ac01ef and other recent review papers in the field). The thesis work will focus on the identification and the scientific-sound assessment of sustainability challenges (mainly in terms of safety and to some extent in terms of environmental impact) of this emerging technology. Indeed, a deeper insight on these aspects is justified according to the experience gained on Li-ion technology (and relating field failures and fire/explosions incidents still observed currently whatever the LIB applications), Further examination of safety and sustainability issues of advanced Na-ion technologies is also needed to anticipate the reinforced mandatory requirements in the field  that will arise by application of the new battery (EU) Regulation that is currently in final stage of discussion at EC level and  that will likely enter into force end of 2022/beginning of 2023.

The thesis plan will comprise:

a) A preliminary examination of the currently emerging Na-ion technology and related gaps of knowledge as well as announced next generations of batteries relying on the NA-ion chemistry, in terms of assessment of safety challenges and their importance versus Li-ion technology:
-  from detailed examination of recent scientific literature 
- and preliminary knowledge gained by the supervising team on early stage Na-ion technology (from key component level to cell level).

b) An experimental evaluation (mainly) of some safety and environmental aspects relying on the use of existing analytic devices (thermal analysis equipment…) existing in both labs as well as fire and ecotoxicity testing equipment (eg FPA ISO 12136, tube furnace, OECD biodegradability or ecotoxicity nench scale testing labs) available at INERIS: at this stage also, testing may include component and prototype cell samples thanks to the collaboration of a key industrial actor in the field (TIAMAT).

Phase a) will ideally end up by the publication of a first overview of these challenges as a review paper in a journal with high impact factor as well as testing plan proposal

Phase b) will first concentrate on complementing existing information on current Na-ion technology (eg comparing electrolyte stability and fire behavior vs Li-ion technology) and then contribute to advance the production of key data relating to the assessment of safe and sustainable development Na-ion cells of second generation (eg characterizing new key components for improved active materials, new electrolytes or new additives). Safety assessments by other tools (if relevant) may also be envisaged.