Li<sup>+</sup> Selectivity of Carboxylate Graphene Nanopores Inspired by Electric Field and Nanoconfinement
Yingying Li, Xing-Yi Yue, Gen Huang, Mei Wang, Qingwen Zhang, Chunchang Wang, Haibo Yi, Shuangyin Wang
Abstract
Abstract The regulation of the ion selectivity by electric field and ion association on the Li + selectivity of carboxyl functionalized graphene nanopores are investigated by molecular dynamics simulation. Carboxylate graphene nanopores of sub‐2 nm exhibit excellent Li + selectivity under the electric field of 1.0 V nm −1 . The results show that ion association inspired by electric field may be a key factor affecting ion selectivity of sub‐2 nm nanopores. The ion association of Mg 2+ and Cl − can be promoted obviously near the nanopores under the electric field of 1.0 V nm −1 . The migrating of Mg 2+ can be retarded by stable clusters of Mg 2+ and Cl − formed near nanopores. The degree of association of Li + with Cl − is relatively low and the disassociation of the Li + cluster is easier so that Li + can more easily pass through the nanopores. These results gain insight into the effect of ion association inspired by electric field and nanoconfinement of graphene nanopore on Mg 2+ /Li + separation, and provide helpful information for the application of nanoporous materials in extraction of Li + ion from salt‐lake brine.