LLZTO crosslinks form a highly stretchable self-healing network for fast healable all-solid lithium metal batteries.

A robust and fast healable composite solid-state electrolyte is developed by using functionalized LLZTO nanoparticles as the dynamic covalent crosslinking points, which exhibits long cycling stability and superior safety in lithium metal batteries even under abuse conditions. [Display omitted] • A novel strategy is proposed by utilizing LLZTO nanoparticles as crosslinking points to form dynamic imine bonds. • The abundant dynamic imine bonds endow the crosslinked network with rapid healing capabilities. • The stability of the battery is demonstrated by the long cycle life of symmetric cells and the abuse resistances of pouch cells. Flexible composite solid electrolytes (CSEs) show great potentials in high-energy all-solid-state lithium metal batteries owing to their easy fabrication, good electrochemical properties, and high safety. However, it remains challenging to achieve good interfacial compatibility between the inorganic fillers and polymer matrix, which affects the lithium-ion transport efficiency and electrochemical performances of CSEs. Herein, a dynamic crosslinked network with Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO) nanoparticles as the cross-linking point is proposed for fabrication of a rapidly self-healing flexible CSE, which is signed as SHENE. The amino groups in the 3-aminopropyltriethoxysilane modified LLZTO behave as the bridge sites to react with the copolymer of 2-hydroxyethyl methacrylate- g -4-formylbenzoic acid and poly (ethylene glycol) methoxy acrylate to form imine bonds, which effectively connect the organic/inorganic interface. Compared to the traditional physical contact, the covalent imine bonds can not only enhance the interaction between the two phases, but also improve the dispersion of the ceramic LLZTO nanoparticles. Additionally, the dynamic reversibility of imine bonds allows for enhanced mechanical strength and self-repairing capabilities of SHENE. Therefore, a Li||Li symmetrical cell assembled with SHENE can stably cycle for 5000 h at 0.05 mA cm −2 and 25 °C. The corresponding Li/SHENE/LiFePO 4 full battery also exhibits good rate performance under various C-rates. Additionally, the Li/SHENE/LFP pouch cell exhibits superior safety under various abuse conditions. Therefore, this work provides new ideas for the uniform dispersion of ceramic nanoparticles in CSEs by the facile design of forming dynamic crosslinked networks. [ABSTRACT FROM AUTHOR]