Ion transport structure using two-dimensional nanomaterial having defects, method for preparing same and lithium extraction apparatus comprising same

Abstract

The present invention relates to an ion transport structure using a two-dimensional nanomaterial having defects, a method for preparing same, and a lithium extraction apparatus comprising same. According to the present invention, by using a structure in which nanoflakes covering defects are grown on a two-dimensional nanomaterial membrane with the defects, unidirectional transport of cations is possible and an ion channel with a controlled size can be formed. Therefore, the ion transport structure of the present invention has excellent ion transport properties and selectivity, and thus can be usefully applied to various fields that require selective transport of ions. In particular, when a lithium ion transport structure is prepared according to the present invention and applied to a separator of a lithium extraction device, high-purity lithium can be efficiently extracted.

1 . An ion transport structure, comprising a membrane made of a two-dimensional nanomaterial having defects; and nanoflakes which are located on one surface of the membrane and formed to cover the defects, and
 having a primary ion channel formed by the defects, and a secondary ion channel formed by an interlayer gap between the membrane and the nanoflake.   
     
     
         2 . The ion transport structure of  claim 1 , wherein the membrane and the nanoflake, each independently, consist of nanomaterials selected from the group consisting of graphene, transition metal dichalcogenides (TMD), hexagonal boron nitride (hBN), and halide perovskite. 
     
     
         3 . The ion transport structure of  claim 1 , wherein the defects comprise at least one selected from vacancies and grain boundaries. 
     
     
         4 . The ion transport structure of  claim 1 , wherein the defects carry a negative charge. 
     
     
         5 . The ion transport structure of  claim 1 , wherein the membrane has a multilayer structure comprising 2 to 20 layers of two-dimensional nanomaterials. 
     
     
         6 . The ion transport structure of  claim 1 , wherein the primary ion channel has a size of 1 to 100 nm. 
     
     
         7 . The ion transport structure of  claim 1 , wherein the secondary ion channel has a size of 0.2 to 1 nm. 
     
     
         8 . The ion transport structure of  claim 1 , wherein the ion is a lithium ion. 
     
     
         9 . A method for preparing an ion transport structure, comprising
 a step of depositing a first nanomaterial on a substrate to form a membrane made of a two-dimensional nanomaterial having defects; and   a step of depositing a second nanomaterial on the membrane to form nanoflakes over the defects.   
     
     
         10 . The method of  claim 9 , wherein the deposition of the first nanomaterial and the deposition of the second nanomaterial are performed by chemical vapor deposition (CVD). 
     
     
         11 . The method of  claim 9 , wherein the deposition of the first nanomaterial is performed at a temperature of 800 to 1,200° C., and the deposition of the second nanomaterial is performed at a temperature of 500 to 900° C. 
     
     
         12 . A lithium extraction apparatus, comprising
 an anodic cell comprising an anode and a lithium ion-containing solution;   a cathodic cell comprising a cathode and an acidic solution; and   the ion transport structure according to  claim 1 , interposed between the anodic cell and the cathodic cell.   
     
     
         13 . The lithium extraction apparatus of  claim 12 , wherein the solution level of the acidic solution in the cathodic cell is lower than the solution level of the lithium ion-containing solution in the anodic cell. 
     
     
         14 . The lithium extraction apparatus of  claim 12 , wherein the lithium ion-containing solution comprises seawater or brine. 
     
     
         15 . The lithium extraction apparatus of  claim 12 , wherein the acidic solution comprises at least one acid selected from the group consisting of hydrochloric acid (HCl), sulfuric acid (H 2 SO 4 ), nitric acid (HNO 3 ), and phosphoric acid (H 2 PO 4 ).