A self-healing composite solid electrolyte with dynamic three-dimensional inorganic/organic hybrid network for...

Composite solid electrolytes (CSEs), which combine the advantages of solid polymer electrolytes and inorganic solid electrolytes, are considered to be promising electrolytes for all-solid-state lithium metal batteries. However, the current CSEs suffer from defects such as poor inorganic/organic interface compatibility, lithium dendrite growth, and easy damage of electrolyte membrane, which hinder the practical application of CSEs. Herein, a CSE (PBHL@LLZTO@DDB) with polyurethane (PBHL) as the polymer matrix and Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) modified by silane coupling agent (DDB) as inorganic fillers (LLZTO@DDB) has been prepared. Disulfide bond exchange reactions between PBHL and LLZTO@DDB enable PBHL@LLZTO@DDB to form a dynamic three-dimensional (3D) inorganic/organic hybrid network, which promotes the uniform dispersion of LLZTO in PBHL@LLZTO@DDB, improves the Li⁺ conductivity (1.24 ± 0.08 × 10^-4 S cm^-1 at 30 ℃), and broadens the electrochemical stability window (5.16 V vs. Li⁺/Li). Moreover, a combination of hydrogen bonds and disulfide bonds endows PBHL@LLZTO@DDB with excellent self-healing properties. As such, both all-solid-state symmetric and full cells exhibit excellent cycle performance at ambient temperature. More importantly, the healed PBHL@LLZTO@DDB can almost completely restore its original electrochemical properties, indicating its application potential in flexible electronic products.