Fabrication of single-ion conducting polymer-coated separators and their application in nonaqueous Li-O2 batteries

Nonaqueous lithium-oxygen (Li-O2) batteries have attracted increasing attention as potential candidates for next-generation batteries due to their significantly high theoretical energy densities. However, they are still in their infancy due to numerous problems. In this study, a cross-linked single-ion conducting polymer network with a highly delocalized anionic group was coated onto a thin commercial polyethylene membrane separator via a facile UV polymerization method. The resulting polymer coating improves the electrolyte wettability and suppresses the diffusion of anionic species across the separator. The effect of the polymer modification of the separator on the electrochemical properties of nonaqueous Li-O2 cells was investigated. A facile modification method for a commercial polyethylene membrane separator using a cross-linked single-ion conducting polymer network with a highly delocalized anionic group was developed. A cross-linker, poly(ethylene glycol) diacrylate, and a delocalized anionic monomer, lithium (4-styrenesulfonyl)(trifluoromethanesulfonyl)imide, were used to modify the surface of the polyethylene separator via UV-initiated polymerization. The resulting polymer coating improves the electrolyte wettability and suppresses the diffusion of anionic species across the separator. The effect of the polymer modification of the separator on the electrochemical properties of nonaqueous Li-O2 cells was investigated.