Vanessa Schenker, Stephan Pfister

Lithium (Li) is essential for decarbonization strategies, such as electric vehicles and renewable energy storage, experiencing the largest growth rates among metals required for low-carbon technologies. To meet this demand, the raw materials sector must increase current capacities and develop new ones at untapped deposits. Understanding life cycle impacts is crucial to avoid severe environmental burden shifts in the future. Although site-specific life cycle inventories exist, they do not allow for a comprehensive global assessment of the Li sector, particularly in capturing technological developments. To address this, our study presents a life cycle inventory model for brines that maintains essential site-specific parameters while providing a global perspective. We define core parameters for site-specific modeling of Li carbonate (Li2CO3) production and develop a systematic approach to addressing data gaps. Our model employs a class-based structure for 30 mapped processes from the literature, and quantifies environmental and technical flows. Overall, we cover 25 sites, representing 300 kilotonnes (90\%) of current Li2CO3 production from brines and an additional 315 kilotonnes of potential future production. One key finding is that sites using direct Li extraction have 6-fold higher climate change impacts than sites using conventional technologies on average while water scarcity impacts are doubled on average. The difference is a result of the larger brine mass required to be treated due to lower Li grades. Furthermore, our model allows the implications for Li-ion battery production to be analysed. Based on our findings, we discuss decarbonization strategies for the Li sector to support a sustainable transition to a low-carbon society.