Safety Enhancement of Rechargeable Lithium Battery By Using Quasi-Solid-State Electrolyte Based on Thiol-Ene Click Chemistry

Abstract

Lithium-ion batteries (LIBs) have been dominant power sources for various applications such as mobile electronic devices, electric vehicles and energy storage systems. However, liquid electrolyte currently used in LIBs has critical drawbacks such as high flammability and leakage problem. In this regard, various electrolyte systems have been studied to replace liquid electrolyte for enhancing the battery safety while maintaining the battery performance. Among them, the chemically cross-linked gel polymer electrolytes can enhance the thermal safety of LIBs by encapsulating organic solvent in the polymer matrix. However, they usually contain a large amount of organic solvents to achieve high ionic conductivity, and side reactions may occur during the cross-linking reaction. To overcome these problems, quasi-solid-state electrolytes are synthesized through thiol-ene click reaction, since the click reaction avoids side reactions and drives fast cross-linking under mild reaction conditions. The quasi-solid-state electrolyte was applied to the lithium-ion cell composed of graphite anode and LiNi0.6Co0.2Mn0.2O2 cathode. The cell employing quasi-solid-state electrolyte exhibited the enhanced safety compared with the liquid electrolyte-based cell and better cycling performance than all-solid-state lithium batteries at ambient temperature. Our result demonstrate that the quasi-solid-state polymer electrolytes are very promising electrolytes for achieving high performance and enhancing battery safety.