Self-healing polyurethane-based polymer electrolyte with high strength for all-solid-state lithium metal batteries

Polyethylene oxide, as one of the most common polymers, has been extensively studied for solid-state polymer electrolytes. However, its poor mechanical properties and low ionic conductivity severely limit its application. Herein, a series of double dynamic self-healing polyurethane polymer electrolyte (PUSPE-X) with hydrogen bonds and dynamic urea bonds was prepared by a simple polycondensation reaction. The constructed network exhibits excellent mechanical properties, strong self-healing and good shape memory properties. Benefiting from the oxygens in the PEG segment and the nitrogen atom in the imide (–NH–) group simultaneously act as electron donor to form coordination bonds with lithium ions by coulombic interaction, further promoting the anion and cation of the lithium salt to dissociate, the PUSPE-6000 demonstrates good ion conductivity of 0.127 m S cm−1 and satisfactory lithium-ion transference number (tLi+=0.55) at 60 °C. The Li|PUSPE-6000|Li symmetric cell works stable for 1200 h at 0.1 mA cm−2 and the LFP|PUSPE-6000|Li cell also achieves excellent cycling stability. The flexible battery based on PUSPE-6000 can continue to work under a variety of harsh conditions, which expand the choice for the all solid-state electrolyte in the flexible wearable electronic device.