Self-healing composite polymer electrolyte formed via supramolecular networks for high-performance lithium-ion batteries

Abstract

A novel supramolecular network-reinforced and self-healing composite polymer electrolyte (SHCPE) is designed and fabricated via the incorporation of ureido-pyrimidinone (UPy)-functionalized SiO₂ (SiO₂–UPy) into the polymer matrix containing UPy units. The bonded UPy groups on SiO₂ could form supramolecular networks with the polymer via the interactions of quadruple hydrogen bonding. Benefitting from the supramolecular interactions, the fillers of SiO₂–UPy are able to uniformly disperse and reduce the agglomeration. As a result, the interphase between SiO₂ and the polymer matrix, which is crucial to provide a fast conduction channel for lithium ions, is increased. Consequently, the SHCPE exhibits an enhanced ionic conductivity of 8.0 × 10⁻⁵ S cm⁻¹ at 30 °C compared with that of the CPE blended with pristine SiO₂. More importantly, the self-healing and mechanical properties of the SHCPE are simultaneously improved due to the increase of physically cross-linked sites in the polymer matrix. Owing to these outstanding properties, the lithium-ion batteries fabricated using the SHCPE exhibit stable cycling performance.