A Dual‐Crosslinking Design for Resilient Lithium‐Ion Conductors

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/LiFePO4 cell with this resilient electrolyte can operate at room temperature with a high cathode capacity of 152 mAh g−1 for 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. For solid polymer electrolytes there is typically a tradeoff between mechanical and electrochemical performance. An elastic Li‐ion conductor with dual covalent and dynamic hydrogen bonding crosslinks is synthesized to provide high mechanical resilience without sacrificing the ionic conductivity. A solid‐state full cell with this resilient electrolyte can maintain operation even after being subjected to intense mechanical impact testing.