Polyacrylonitrile hybrid membrane coated with aluminum hydroxide for separating lithium

In this study, we developed a method for fabricating an aluminum hydroxide coated polyacrylonitrile (PAN) nanofiber for separating lithium from aqueous solutions. Lithium was collected on lithium aluminum layered double hydroxide (LDH) produced from an aluminum metal layer on a PAN membrane. The aluminum metal layer on the PAN membrane was prepared by controlling the deposition rate and time of thermal evaporation to produce a uniform metal coating. The PAN@LiAl₂-LDH membranes adsorbed 2.2 μg Li/cm² on the 40-nm thick aluminum metal layer coated PAN membrane, and lithium was then desorbed in deionized water at 90 °C. A new method for manufacturing free standing LiAl₂-LDH nanofiber membranes was developed by removing the PAN nanofibers from PAN@LiAl₂-LDH to improve the thermal stability. We measured kinetic data for lithium intercalation and deintercalation as 0.44 μg Li/min and 0.55 μg Li/min, respectively, thereby suggesting that the proposed method is more efficient for separating lithium compared with other hybrid membranes.