Molecular Engineering of Elastomeric Electrolytes with Enhanced Mechanical Robustness for Lithium Metal Batteries

The mechanical robustness of polymer electrolytes is a critical factor for achieving stable lithium metal battery operation, as repeated lithium plating and stripping induce continuous mechanical deformation that can lead to irreversible deformation, crack formation, interfacial delamination, and cycling instability. Here, we present a molecular engineering strategy to selectively enhance the mechanical robustness of acrylate-based elastomeric electrolytes by controlling polymer chain rotational dynamics within the polymer network. Through molecular design that regulates internal chain mobility while preserving electrochemically active functionalities, the designed electrolyte exhibits substantially improved resistance against structural and interfacial failure without compromising ionic conductivity and electrochemical stability. This strategy effectively stabilizes the electrolyte structure and electrode interface during repeated electrochemical cycling, demonstrating a molecular-level design approach for durable elastomeric electrolytes for long-term stable lithium metal batteries.