Electrochemical Lithium Extraction from Brines Using Dopant-Tailored Titanate Electrodes, with Co-Recovery of Carbonates, Acids, and Bases

Advances in modular separation technologies are crucial for enabling the co-recovery of multiple high-value products from complex and heterogeneous resources such as produced water. The co-recovery of multiple high-value products serves as a hedge against market volatility associated with producing a single product and lowers the quantity of waste that needs to be disposed. In a significant departure from conventional evaporation and chemical precipitation routes to recover lithium, which are slow, resource- and energy-intensive, selective electrochemical recovery of lithium is realized using a self-supported, dopant-engineered H2Ti3O7 electrode. The binder-free architecture, directly grown on titanium foil via hydrothermal synthesis, ensures strong mechanical stability and rapid ion transport. Li+ capture capacity as high as ∼211 ± 15 mg·g–1 is achieved using Nd-doped H2Ti3O7 at –0.9 V vs Ag/AgCl. The separation of Mg2+ and Ca2+ ions via the formation of Mg(OH)2 and CaCO3 (using CO2) is essential for the subsequent reuse of the brine for the electrochemical co-recovery of 0.2–0.3 M NaOH and HCl. Therefore, this work unlocks advances in comprehensive valorization of brine for the co-recovery of multiple high-value critical and commodity materials essential for energy and environmental security and sustainability.