Zwitterionic Matrix with Highly Delocalized Anionic Structure as an Efficient Lithium Ion Conductor

The leakage and volatilization of liquid electrolytes raise potential safety risks in the development of electrochemical energy storage devices with high energy density.Herein,novel solid-state zwitterionic materials containing sulfonyl imide as a highly delocalized anionic structure were synthesized for highly targeted lithium ion conducting matrices.The influences of the molecular structure characteristics on thermal behavior and electrochemical property were investigated comprehensively.Due to the weak Coulomb interaction between the sulfonyl imide moiety and cationic species,the rationally designed zwitterionic electrolytes showed a high conductivity of 0.44 mS cm^(-1).And the obtained high lithium ion transference number of 0.43 is four times higher than that of the widely employed sulfonate analogues.Additionally,excellent cycling stability of the lithium plating/stripping process and super resistance to electrochemical oxidation(up to 5.5 V)were observed.This molecular engineering strategy for lithium ion conductor advances new possibilities for developing solvent-free and non-migrating electrolyte matrix materials for lithium metal batteries.