Low-cost and stable Li_1.5Al_0.3Ti_1.7Si_0.2P_2.8O₁₂ glass–ceramics for lithium extraction from seawater

Rapid development of electronic and grid storage technologies based on lithium-ion batteries are leading to tight supply of lithium resources in the future. Extracting lithium from seawater can completely solve the problem of lithium resource shortage. An electro-deposition method based on a lithium superionic conductive solid-state electrolyte, Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP), has been reported to obtain metallic lithium from seawater. However, expensive LAGP increases the cost of lithium extraction, while Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) with relatively lower prices cannot meet the stable requirements. Herein, a low-cost, stable glass–ceramics, Li_1.5Al_0.3Ti_1.7Si_0.2P_2.8O₁₂ (LATSP), has been prepared for lithium extraction from seawater. The LATSP glass–ceramics show good selectivity towards Li⁺ and exhibit a high ionic conductivity of 3.98 × 10⁻⁴ S cm⁻¹ at 22 °C. After soaking in simulated seawater, LATSP showed much better stability than LATP, comparable to LAGP. The resultant LATSP glass–ceramics was successfully employed in a seawater lithium extraction device, with a high lithium extraction Coulombic efficiency of 94.0%. Moreover, the LATSP exhibits an ionic conductivity of 2.80 × 10⁻⁴ S cm⁻¹ and maintains a complete structure after 45 h of lithium extraction. This work presents an effective and practical Li-ion conducting membrane for lithium extraction from seawater.