Self-healing poly(ionic liquid)-type electrolytes based on multiple dynamic interactions for lithium batteries

Self-healing polymer electrolytes are in high demand for enhancing the cycle stability and reliability of flexible and wearable electronics. Herein, a healable, nonflammable poly(ionic liquids) (PIL) electrolyte is fabricated. It is based on an imidazolium-type PIL copolymer that contains cross-linkers with a disulfide bond and hydrogen bond (SSH), ionic liquid, and lithium salt. The prepared SSH-PIL electrolytes display high ionic conductivity and outstanding self-healing capacity due to multiple dynamic interactions. The optimized SSH-PIL2 electrolyte films exhibit superior ionic conductivity (exceeding 10 –4 S cm −1 at 30 °C), a wide electrochemical stability window (5.2 V vs. Li/Li + ), and a high lithium-ion transference number (0.43). The assembled LiFePO 4 /SSH-PIL2/Li cell delivers a specific discharge capacity of 153.3 mAh g −1 at 0.1 C, and a capacity retention of 93.3% after 100 cycles. More significantly, the SSH-PIL2 electrolyte can quickly repair mechanical damage (within 20 min at 60 °C). The healing efficiency in terms of mechanical properties and specific discharge capacity is as high as 94.6% and 98.0%, respectively. This work presents a promising approach for developing reliable and safe electronic devices.