A Self-Healing and Nonflammable Cross-Linked Network Polymer Electrolyte with the Combination of Hydrogen Bonds and Dynamic Disulfide Bonds for Lithium Metal Batteries

The self-healing solid polymer electrolytes (SHSPEs) can spontaneously eliminate mechanical damages or micro-cracks generated during the assembly or operation of lithium-ion batteries (LIBs), significantly improving cycling performance and extending service life of LIBs. Here, we report a novel cross-linked network SHSPE (PDDP) containing hydrogen bonds and dynamic disulfide bonds with excellent self-healing properties and non-flammability. The combination of hydrogen bonding between urea groups and the metathesis reaction of dynamic disulfide bonds endows PDDP with rapid self-healing capacity at 28 °C without external stimulation. Furthermore, the addition of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide (EMIMTFSI) improves the ionic conductivity (1.13 × 10⁻⁴ S cm⁻¹ at 28 °C) and non-flammability of PDDP. The assembled Li/PDDP/LiFePO₄ cell exhibits excellent cycling performance with a discharge capacity of 137 mA h g⁻¹ after 300 cycles at 0.2 C. More importantly, the self-healed PDDP can recover almost the same ionic conductivity and cycling performance as the original PDDP.