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

Shuang, Zong-Yao; Zhao, Chen-Zi; Huang, Xue-Yan; Gao, Yu-Chen; Xu, Pan; Fu, Fang; Oh, Young; Kong, Wei-Jin et al. · Sci Adv · 2026

basic_science · Level V

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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<sup>+</sup> 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<sub>0.9</sub>Co<sub>0.05</sub>Mn<sub>0.05</sub>O<sub>2</sub> (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<sup>-1</sup>. 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.