Highly stable cation-exchange membranes for lithium recovery from acidic lithium ore leachate

Electrodialysis technology is widely deployed in the field of separation due to its simplicity of operation and sustainability, where ion-exchange membranes are the most critical components in this process. Traditional cation-exchange membranes are typically suitable for mild conditions and often suffer from issues such as poor stability and susceptibility. In this study, we design a novel cation-exchange membrane featuring a rigid backbone with sulfonic acid groups as side chains and fluorine-containing region. The resultant membrane exhibits high thermal stability, acid resistance, and oxidation resistance, without degradation of functional groups and decline in mechanical strength after treatment in 1 ​mol ​L⁻¹ HCl solution at 60 ​°C for over 1000 ​h. Moreover, its oxidation resistance in Fenton reagent at 80 ​°C surpasses that of commercial membranes. The Li⁺ recovery ratio from acidic leach liquors of lithium ores can reach ∼99.6 ​% via the electrodialysis process, demonstrating the membrane as a candidate for lithium extraction in aggressive industrial scenarios.