Boosting the performances of lithium metal batteries through in-situ construction of dual-network self-healing gel polymer electrolytes

Abstract

As an alternative to conventional liquid electrolytes, self-healing gel polymer electrolytes (SHGPEs) can effectively increase the safety performance and lifetime of lithium metal batteries (LMBs). However, the poor mechanical properties and unfavorable ionic conductivity limit its further use. Herein, based on a simple in situ polymerization strategy, a novel dual-network structure self-healing gel polymer electrolyte (DN-SHGPE) with mechanical strength and self-healing properties is designed and prepared. The brush copolymer PEG-UPy contains a large amount of dynamic urethane-pyrimidine (UPy) dimer, acting as the first network, which gives GPE great self-healing ability and increases the safety and cycle lifetime of lithium batteries. The second network is cross-linked polyethylene glycol diacrylate (PEGDA), which ensures the dimensional stability and mechanical qualities of GPE. In comparison to the unmodified polymer electrolyte PEG-UPy, DN-SHGPE exhibits better ionic conductivity, excellent mechanical property, and good thermal stability, as well as good interaction stability with Li metal anode. When assembled with LiFePO4 and lithium metal electrodes, the resultant cells show a high reversible specific capacity and good rate capability.