Future Environmental Performance of Lithium from Brines Shaped by Energy and Reagent Decarbonization and Technology Optimization.

The rapid expansion of battery-grade lithium carbonate (Li2CO3) production from brines raises increasing concerns about future environmental impacts, which must be assessed in alignment with project commissioning timelines. Here, we assess the life cycle climate change and water scarcity impacts for 24 operating and announced brine-based Li2CO3 projects, accounting for future technology optimization and economy-wide decarbonization across the energy and chemical reagent sectors. These developments could reduce climate change impacts of individual projects by 26-89% by 2035. Substantial project-level mitigation does not necessarily translate into lower impact intensity in the Li2CO3 supply mix of these projects, which depends on the success of planned production capacity. Technology optimization and economy-wide decarbonization can only offset the higher impacts from announced projects, while achieving meaningful cuts requires a transition to electrified heating. This shift, combined with more resource-intensive direct lithium extraction (DLE) technologies, may exacerbate water scarcity impacts beyond production sites. Building a sustainable lithium supply chain demands early mitigation to counterbalance higher impacts of upcoming projects, heat decarbonization as an immediate rather than long-term goal, accelerated decarbonization of soda ash and lime industries, and a supply chain-wide approach to water management.