Accelerated ion transportation in liquid crystalline polymer networks for superior solid-state lithium metal batteries

Abstract

The application of solid polymer electrolyte in high energy density lithium metal batteries is limited by low Li+ mobility, low ionic conductivity and poor cycle stability at room temperature. In the study, the free-standing flexible polymeric electrolytes (PCREs) with semi-interpenetrating-network in the topological nanostructures were fabricated through the in-situ UV-photopolymerization of the liquid crystalline monomers and poly(ethylene glycol) diglycidyl ether. Remarkably, by optimizing the relative proportion of the two liquid crystalline monomers with different methylene chains as connected bridge band between rigid center and terminal acrylate functional groups, the electrochemical properties of the prepared PCREs were successfully improved, which might contributed to the suitable ion transport channels in the porous polymer network structures. The prepared PCRE exhibited increased ion migration number, excellent ionic conductivity and a wide electrochemical window. Through the calculation of density functional theory and molecular dynamics simulation, the difference in the molecular orbital of liquid crystalline polymers and the mechanism of PCREs enhancement tLi+ were well understood. The study may provide new perspectives for the design and fabrication of high-performance polymer electrolyte materials, which will promote the development and practical application of the all-solid lithium metal batteries.