A critical barrier to overcome in the development of solid‐state electrolytes for lithium batteries is the trade‐off between sacrificing ionic conductivity for enhancement of mechanical stiffness. Here, a physically cross‐linked, polymer‐supported gel electrolyte consisting of a lithium salt/ionic liquid solution featuring a fully zwitterionic (ZI) copolymer network is introduced for rechargeable lithium‐based batteries. The ZI scaffold is synthesized using a 3:1 molar ratio of 2‐methacryloyloxyethyl phosphorylcholine and sulfobetaine vinylimidazole, and the total polymer content is varied between 1.1 and 12.5 wt%. Room‐temperature ionic conductivity values comparable to the base liquid electrolyte (≈1 mS cm−1) are achieved in ZI copolymer‐supported gels that display compressive elastic moduli as large as 14.3 MPa due to ZI dipole–dipole cross‐links. Spectroscopic characterization suggests a change in the Li+coordination shell upon addition of the zwitterions, indicative of strong Li+···ZI group interactions. Li+transference number measurements reveal an increase in Li+conductivity within a ZI gel electrolyte (
Solid‐state electrolyte materials are attractive options for meeting the safety and performance needs of advanced lithium‐based rechargeable battery technologies because of their improved mechanical and thermal stability compared to liquid electrolytes. However, there is typically a tradeoff between mechanical and electrochemical performance. Here an elastic Li‐ion conductor with dual covalent and dynamic hydrogen bonding crosslinks is described to provide high mechanical resilience without sacrificing the room‐temperature ionic conductivity. A solid‐state lithium‐metal/LiFePO4cell with this resilient electrolyte can operate at room temperature with a high cathode capacity of 152 mAh g−1for 300 cycles and can maintain operation even after being subjected to intense mechanical impact testing. This new dual crosslinking design provides robust mechanical properties while maintaining ionic conductivity similar to state‐of‐the‐art polymer‐based electrolytes. This approach opens a route toward stable, high‐performance operation of solid‐state batteries even under extreme abuse.
more » « less- NSF-PAR ID:
- 10074837
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 30
- Issue:
- 43
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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