Self-Healing Polymer Electrolytes Formed via Dual-Networks: A New Strategy for Flexible 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.