Chemically Cross-Linked Gel Polymer Electrolytes for Highly Safe Lithium-Ion Batteries with Good Cycling Stability

Abstract

Liquid electrolytes used in lithium-ion batteries have many drawbacks such as high flammability, high reactivity toward electrode materials and solvent leakage. To overcome these problems, most recent research has focused on synthesis and characterization of highly conductive gel polymer electrolytes containing large number of organic solvents in the polymer matrix. However, there are still many hurdles to overcome before they can be applied to lithium-ion batteries. Since a large amount of organic solvent is required to achieve high ionic conductivity, battery safety is not significantly enhanced. In this study, we synthesized chemically cross-linked gel polymer electrolyte containing small amounts of organic solvents. The chemically cross-linked gel polymer electrolyte enhanced thermal safety of battery due to the effective trapping ability of organic solvents in the polymer matrix. The resulting gel polymer electrolyte was applied to lithium-ion cells composed of graphite anode and LiNi0.6Co0.2Mn0.2O2 cathode. We investigated their electrochemical performance, thermal stability, and solvent leakage behavior.