POSS hybrid poly(ionic liquid) ionogel solid electrolyte for flexible lithium batteries

Traditional lithium-ion batteries based on liquid electrolytes cannot adapt to the increasing and various highly flexible requirements. In this work, a confinement-driven strategy has been developed to confine the ionic liquids in a polyhedral oligomeric silsesquioxanes (POSS) and poly(ethylene glycol) diacrylate (PEGDA) hybrid crosslinked poly(ionic liquid)s ionogel (POSS-CPIL-n), which endows this novel electrolyte superior flame retardancy and dramatically flexibility. The POSS-CPIL-n ionogel renders exceptional flexibility (bend, fold and twist) and desired mechanical properties (2.5 MPa). Advantageous for high dissociation of lithium salt, high ionic conductivity (2.5 mS cm- 1 at 25 degrees C) and considerable lithium ion mobility (0.51) are provided. Thanks to the flexibility of ionogel electrolyte together with excellent thermal and electrochemical stability, the LiFePO4||Li cell based on POSS-CPIL-n exhibits significant rate performance and cycling stability, the capacity of the cell can reach to 100 mAh g-1 at 4 C and maintain a substantial discharge capacity of 160.5 mAh g-1 after 200 cycles at 0.2C. Furthermore, the soft-package assembled with POSS-CPIL-n can successfully charge a cell phone and continue to supply power stably even when the battery is exposed to the air, which indicates that POSS-CPIL-n has a promising potential application in high safety flexible electronic devices.

Automated summary

A novel polymer poly(ionic liquid)s ionogel with excellent flexibility and flame retardancy has been developed in this study. The ionogel shows high ionic conductivity and lithium ion mobility, leading to significant rate performance and cycling stability in batteries. It has potential applications in high safety flexible electronic devices.