Development of ionic liquid electrolyte with anion receptor as an additive for lithium metal battery

Abstract

As the electric vehicle market grows rapidly, it is necessary to develop next-generation batteries that exceed the energy density limit of existing lithium-ion batteries. Among them, a lithium metal battery using a lithium metal having a high theoretical capacity, a low reduction potential, and a low density as an anode is being actively researched because it can realize higher energy density than conventional lithium ion batteries. However, the low coulombic efficiency due to the continuous reaction between lithium metal and the electrolyte and the safety problem caused by the growth of lithium dendrites have not yet been solved. Therefore, for the commercialization of lithium metal batteries, it is necessary to develop intrinsically nonflammable electrolyte system. In this study, by adding the anion receptor TTFEB to the pyrrolidinium-based ionic liquid, the ion conductivity of lithium ion was improved, and stable passivation film was induced, and the driving current density could be raised more than four times. Although there are still difficulties in cell operation at high current density, the significance of this study is to develop an ionic liquid electrolyte system using anion receptors to pioneer the field of battery introduction technology that guarantees safety.