Dipole–dipole interaction facilitates anion-rich solvation structures in polymer electrolytes for solid-state lithium metal batteries

Abstract

Polymer electrolytes are vital for safe and high-energy–density lithium metal batteries but face challenges from interfacial instability and Li dendrites. Here, we report a molecular design exploiting dipole–dipole interactions to tailor Li + solvation structures and interfacial chemistry. Incorporating pentafluorophenyl acrylate into the polymer backbone enhances dipole interactions with 1,2-dimethoxyethane solvent, modulating the solvation structure and promoting anion entry into the primary coordination sphere. The anion-rich environment facilitates a durable, LiF-dominated solid electrolyte interphase, effectively suppressing dendrites and improving interfacial stability. The resulting electrolyte enables stable lithium plating/stripping over 2000 hours in symmetric cells and extends Li||LiNi 0.9 Co 0.05 Mn 0.05 O 2 (NCM90) full cell cycling to 1000 cycles at 1.0 C. An anode-free Cu||NCM90 pouch cell delivers a high-energy–density of 579 Wh kg −1 . This study underscores the critical role of dipole-mediated solvation structuring in polymer electrolytes and offers a generalizable approach toward high-performance, energy-dense solid-state batteries.