Electrochemical lithium capture using titanate materials: mechanistic insights and proposed advances
摘要
The rising demand for lithium in energy storage technologies requires the development of sustainable and selective recovery methods from unconventional, earth-abundant brine resources. Moving beyond traditional lithium mining and pH-swing-driven ion exchange, electrochemical pathways offer a promising, environmentally friendly alternative for lithium capture. In this perspective, we explore the potential of H2TiO3 (HTO) ion-sieve materials, widely known for their pH-driven lithium selectivity, in a membrane-free, single-cell electrochemical system. This approach leverages an applied voltage bias (−1.2 V vs. Ag/AgCl) to enhance lithium concentration at the electrode surface, driving the H⁺-Li⁺ exchange without external pH adjustment. Under these conditions, lithium adsorption capacity reached 9.61 ± 0.2 mg/g, over six times higher than in the physisorption control. The system also demonstrated superior lithium selectivity over competing cations in complex brine, with separation factors of 32.41 for Li+/Na+, 43.5 for Li+/K+ and 7.6 for Li+/Mg2+. By eliminating the need for chemical pH swings and enabling electricity-driven lithium enrichment at the electrode interface, this approach highlights the potential of electrochemical pathways for sustainable, selective lithium recovery from complex brine feedstocks. Future directions for advancing material design, selectivity mechanisms, and process-level optimization are discussed to guide further research in this emerging field.