Self‐Healing and Flexible Ionic Gel Polymer Electrolyte Based on Reversible Bond for High‐Performance Lithium Metal Batteries

Abstract

The low ionic conductivity, poor interface contact, and low safety of the electrolytes are the main problems in the practical application in flexible lithium metal batteries. A new type of chemical crosslinked ionic gel polymer electrolyte (IGPE) with good self‐healing ability and excellent electrochemical properties is designed based on polyoxyethylenebis(amine), and 1,3,5‐benzenetricarboxaldehyde in the presence of ionic liquid through a one‐step reaction. The interaction between ionic liquid and polymer with the ether oxygen atom of EO chains improves the stability of IGPE and the crystallinity decreased significantly due to the incorporation of ionic liquid. The IGPEs show good self‐healing, film flexibility, and high ionic conductivity even at −25 °C. They also possess high thermal stability, wide electrochemical stability window, and good interfacial compatibility. The Li/IGPE‐50/LiFeO4 battery with IGPE‐50 as an electrolyte is studied and the high discharge capacity of 154.8 mAh g−1 is obtained at 0.1 C with 99.6% of coulombic efficiency, and remains 132.8 mAh g−1 on the 50th cycle. Ionic liquid combined with polymers based on dynamic reversible bonds can optimize the electrochemical performance of IGPEs, and improve its safety and stability, which is very useful for flexible lithium metal batteries.