A Lamellar MXene (Ti3C2Tx)/PSS Composite Membrane for Fast and Selective Lithium-Ion Separation

A two-dimensional (2D) laminar membrane with Li+ selective transport channels is obtained by stacking MXene nanosheets with the introduction of poly(sodium 4-styrene sulfonate) (PSS) with active sulfonate sites, which exhibits excellent Li+ selectivity from ionic mixture solutions of Na+, K+, and Mg2+. The Li+ permeation rate through the MXene@PSS composite membrane is as high as 0.08 mol m(-2) h(-1), while the Li+/Mg2+, Li+/Na+, and Li+/K+ selectivities are 28, 15.5, and 12.7, respectively. Combining the simulation and experimental results, we further confirm that the highly selective rapid transport of partially dehydrated Li+ within subnanochannels can be attributed to the precisely controlled interlayer spacing and the relatively weaker ion-terminal (-SO3-) interaction. This study deepens the understanding of ion-selective permeation in confined channels and provides a general membrane design concept.

Automated summary

The study involves the creation of a 2D laminar membrane with Li+ selective transport channels by stacking MXene nanosheets with poly(sodium 4-styrene sulfonate) (PSS) containing active sulfonate sites. This membrane shows excellent Li+ selectivity in ionic mixture solutions and high Li+ permeation rate. The selective and rapid transport of partially dehydrated Li+ within subnanochannels is attributed to precisely controlled interlayer spacing and weaker ion-terminal interaction.