Self-Healing Single-Ion Conducting Polymer Electrolyte Formed via Supramolecular Networks for Lithium Metal Batteries

Polymer electrolytes (PEs) have been intensively researched in lithium metal batteries (LMBs) due to their good chemical stability, well compatibility with lithium metal electrodes, and high safety. Nevertheless, the typical PEs are dual-ion conductors, which usually suffer from the concentration polarization and cracks. Here, the self-healing single-ion conducting polymer electrolytes (SIPEs) are fabricated to reduce concentration polarization, leading to the suppression of the formation of lithium dendrites and healing of the cracks. The SIPEs are synthesized via reversible addition–fragmentation chain transfer copolymerization of lithium 4-styrenesulfonyl(phenylsulfonyl)imide, 2-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)ethyl methacrylate, and poly(ethylene glycol) methyl ether methacrylate in the absence of additional lithium salts. The obtained PEs (SIPE-5) show a good thermal stability up to 278.4 °C, comparatively high ionic conductivity up to 1.40 × 10–5 S cm–1 at 60 °C, high lithium-ion transference number (tLi+ = 0.89), and good compatibility with the lithium metal anode. The symmetric Li/Li cell remains an extremely stable and low overpotential without short circuiting over the 2800 h cycle at a current density of 0.05 mA cm–2. The Li/LiFePO4 coin cell also exhibits good cycling stability and superior rate performance. Therefore, the synthesized SIPEs possess the potential of the application in LMBs.