Potential-Gated Polymer Integrates Reversible Ion Transport and Storage for solid-state Batteries.

Xu, Ruogu; Xu, Shengjun; Zhang, Xiaoyin; Wang, Yujie; Yu, Tong; Xiao, Ru; Bai, Shuo; Sun, Zhenhua et al. · Adv Mater · 2026

basic_science · Level V

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Abstract

The development of practical solid-state batteries is hindered by their high interfacial resistance and sluggish diffusion properties, primarily due to the heterogeneous interfaces between the solid electrolyte and the electrode. Here, an all-in-one polymer electrode-electrolyte material (P(EO<sub>2</sub>-S<sub>3</sub>)) is presented, which covalently integrates ethylene oxide groups for Li<sup>+</sup> transport and trisulfide linkages for redox-active sites. This material exhibits favorable ionic conductivity as a solid electrolyte, while its reversible redox activity activates below 2.5 V versus Li⁺/Li, delivering a high reversible capacity of 491.7 mAh g<sup>-1</sup>. Leveraging P(EO<sub>2</sub>-S<sub>3</sub>) as both cathode and electrolyte, integrated cells (P(EO<sub>2</sub>-S<sub>3</sub>)@CP|P(EO<sub>2</sub>-S<sub>3</sub>)|Li) exhibit accelerated electrochemical kinetics while maintaining cycling stability in flexible devices over 20 000 bending cycles. As a redox-active catholyte of LiFePO<sub>4</sub>, P(EO<sub>2</sub>-S<sub>3</sub>) increases the capacity of the composite cathode to 358.3 mAh g<sup>-1</sup> based on LiFePO<sub>4</sub> mass, achieving an electrode energy density of 585.9 Wh kg<sup>-1</sup>. This work establishes a new paradigm for multifunctional polymers that integrates ion transport and storage, offering a versatile platform for flexible, high-energy solid-state batteries.