This article reports flexible PEO-based electrolytes with self-healing and highly stretchable properties for lithium-ion batteries.

This article reports a self-healing composite polymer electrolyte formed via supramolecular networks for high-performance lithium-ion batteries.

The cyclophosphazene-based self-healing polymer electrolytes (CPSHPE) is designed and fabricated via the copolymerization of hexa­(4-ethyl acrylate phenoxy) cyclotriphosphazene (HCP), (2-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)­ureido)­ethyl methacrylate) (UPyMA), and poly­(ethylene glycol) methyl ether methacrylate (PEGMA) under UV irradiation. The cross-linking structure formed by HCP could effectively enhance the mechanical strength of the polymer electrolyte, and the cyclotriphosphazene as the core is able to improve the flame-retardant properties. Benefiting from the phenyl groups in HCP and the cross-linking structure, the CPSHPE shows high thermal stability (up to 300 °C). On the other hand, the supramolecular network fabricated by the dynamic ureido-pyrimidinone (UPy) dimers endows the polymer electrolyte with good self-healing capability and is expected to improve the reliability of polymer lithium batteries. Moreover, the cells were fabricated with LiFePO4 (LFP), CPSHPE, and Li anodes show good reversible specific capacity. The CPSHPE could be a promising candidate as the multifunctional polymer electrolyte to improve the safety performance of lithium metal batteries.

A novel polymer electrolyte with mechanically robust and self‐healing properties was fabricated through a dual‐network structure, crosslinked by quadruple hydrogen bonding and chemical bonding. The dynamic ureido‐pyrimidinone (UPy) dimers were the first network in the polymer matrix. This group endows the polymer electrolyte with good self‐healing capacity and improves the reliability and lifetime of the polymer lithium batteries. The crosslinked polyethylene glycol‐bis‐carbamate dimethacrylate (PEGBCDMA) is the second network and guarantees dimensional stability and good mechanical properties of the polymer electrolyte. The dual‐network self‐healing polymer electrolyte (DN‐SHPE) exhibits improved ionic conductivity versus the polymer electrolyte fabricated by poly(ethylene glycol) diacrylate (PEGDA). It has high thermal stability (up to 350 °C) and excellent interfacial stability with the electrodes. When the DN‐SHPE‐based cells were fabricated with LiFePO4 and Li metal, the resulting cells show good reversible specific capacity and considerable rate capability. Moreover, the pouch cell could maintain electrochemical function even under deformation or folding conditions.