A self-healing poly(ionic liquid) block copolymer electrolyte enabled by synergetic dual ion-dipole interactions

Currently, there is a growing demand for self-healing solid polymer electrolytes (SPEs) with high performance for next-generation flexible electronics. Herein, self-healing SPEs (PIBCPEs) have been fabricated by doping poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) in poly(ionic liquid) (PIL) block copolymers. The imidazole cations of the PIL blocks and the oxygen atoms in the poly(ethylene oxide) (PEO) blocks and the -CF3 dipoles in PVDF-HFP formed dual ion–dipole interactions, which not only endowed PIBCPEs with outstanding self-healing capability, but also facilitated lithium ion transport. Molecular dynamics (MD) simulation results exhibited rapid transport of lithium ions in the continuous phase formed by microphase separation. In addition, the electrostatic attraction of the imidazole cations to TFSI- increased lithium ion transference number. PIBCPEs also possessed excellent thermal stability, electrochemical oxidation stability, and good interfacial stability. Based on these advantages, the assembled LiFePO4/PIBCPE_27/Li cell exhibited a high discharge capacity at 0.5 C with capacity retention of 97.1 % after 250 cycles. Importantly, PIBCPEs could restore its ionic conductivity and cycling performance of cell after self-healing, showing a broad potential for applications in flexible and secure wearable device.