Efficient lithium extraction via electrodialysis using acid-processed lithium-adsorbing lithium lanthanum titanate

Increasing demands of lithium (Li) for lithium-ion batteries (LIBs) call for efficient Li extraction methods from natural resources and used LIBs. In this study, we efficiently extract Li from a Li-containing solution via electrodialysis using a fast ion conductor, lithium lanthanum titanate (LLT, Li0.29La0.57TiO3), as a separation membrane. Here, the LLT surface was modified by immersing in a strong acid solution such as hydrochloric acid to adsorb Li ions. For a mixed alkaline solution of lithium hydroxide, sodium hydroxide, and potassium hydroxide with a 0.1-M concentration, the maximum extraction speed of Li reached 3.5 mg/h when 5 V voltage was applied to the ionic conductor membrane with an area of 16 cm2. With the Li-adsorbing LLT, 40 mg of Li was extracted after 72 h from an aqueous solution in which Li was eluted by immersing black powder of used LIBs in water. The result indicates that high alkalinity may play a key role to achieve fast extraction.