Producing battery grade lithium carbonate from salt-lake brine via bipolar membrane carbon dioxide mineralization

Producing battery-grade Li2CO3 product from salt-lake brine is a critical issue for meeting the growing demand of the lithium-ion battery industry. Traditional procedures include Na2CO3 precipitation and multi-stage crystallization for refining, resulting in significant lithium loss and undesired lithium product quality. Herein, we first proposed a bipolar membrane CO2 mineralization technique for directly producing battery-grade Li2CO3 from lake brine that enriches alkali metals (Na+, K+). Results indicate the process can successfully separate Li+ from contaminants and present a selectivity above 900 for Li+ through the CO2 mineralization reaction, while prevent electro-oxidating Cl- to Cl2 pollution. The obtained Li2CO3 production purity is above 99.75% with lithium recovery rate of 86%. Carbon dioxide was captured in the form of Li2CO3, with a capacity of 595 g of CO2 for1 kg of Li2CO3. The technology provides a sustainable and cost-effective path for producing battery-grade Li2CO3 from the lake brine.