In a complex and rapidly evolving technological, socio-economic and geopolitical landscape that is focused on a global “sustainable energy transition,” increased electromobility based on lithium batteries is often stated as a key objective. However, unbeknownst to the public, policy makers and most researchers alike, lithium in its enriched isotopic forms (6Li and 7Li) holds tremendous added value beyond its use in batteries. This is especially true in both present and future nuclear technologies. For those countries with large lithium reserves that are being prospected for rapid lithium exploitation in order to fuel the growing global electromobility sector, it is important to be aware of these added value uses when considering plans for expanding lithium extraction (plans that also hold negative environmental externalities, such as prodigious water use and contamination). Argentina – which has an established nuclear energy and research sector, as well as a current administration that seems committed to rapidly depleting the national lithium reserves – serves as a strong and dynamic case study for the importance of crafting long-term, science-based and sustainable policies around the exploitation and isotopic separation of lithium. Argentina owns almost a third of the lithium reserves in South America which, together with those of Chile and Bolivia, represent more than half of the world’s lithium availability. Battery-grade lithium carbonate (Li2CO3) is produced from the Puna brines in the Andes of Northwestern Argentina – it is exported and only a small fraction remains in Argentina as royalties (around 3%) and the declared profits of the mining companies.  This article analyzes the use of lithium isotopes (6Li and 7Li) in fission and fusion nuclear reactors and in nuclear technology devices, such as scintillation plates, neutron detectors and shields. These uses of lithium in nuclear technologies have the potential to add value to Argentina’s limited lithium reserves...