  By 2035, the need for battery-grade lithium is expected to quadruple. About
half of this lithium is currently sourced from brines and must be converted
from a chloride into lithium carbonate (Li2CO3) through a process called
softening. Conventional softening methods using sodium or potassium salts
contribute to carbon emissions during reagent mining and battery manufacturing,
exacerbating global warming. This study introduces an alternative approach
using carbon dioxide (CO2(g)) as the carbonating reagent in the lithium
softening process, offering a carbon capture solution. We employed an active
learning-driven high-throughput method to rapidly capture CO2(g) and convert it
to lithium carbonate. The model was simplified by focusing on the elemental
concentrations of C, Li, and N for practical measurement and tracking, avoiding
the complexities of ion speciation equilibria. This approach led to an
optimized lithium carbonate process that capitalizes on CO2(g) capture and
improves the battery metal supply chain's carbon efficiency.
