TiO2 nanotubes (as in Fig. 1) were prepared by hydrothermal treatment of TiO2 nanoparticles in NaOH aqueous solution, and the TiO2 ion-sieves for lithium selective adsorption were successfully synthesized via a simple solid-state reaction and acid treatment process from the nanomaterials. The TiO2 nanomaterial have been characterized by XRD, TEM, HRTEM, SAED and BET methods, and the lithium ions adsorption property was tested via the adsorption isotherm and selectivity measurement. Results show that the ion-sieves prepared from different polymorphs have a remarkable selective adsorption capacity for lithium ions from brine or sea water (as in Fig. 2).