Ion bridging enables high-voltage polyether electrolytes for quasi-solid-state batteries.

Hou, Tianyi; Wang, Donghai; Jiang, Bowen; Liu, Yi; Kong, Jia; He, Yanbing; Huang, Yunhui; Xu, Henghui · Nat Commun · 2025

basic_science · Level V

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Abstract

Polyether electrolytes have been widely recognized for their favorable compatibility with lithium-metal, yet they are hampered by intrinsically low oxidation thresholds, limiting their potential for realizing high-energy Li-metal batteries. Here, we report a general approach involving the bridge joints between non-lithium metal ions and ethereal oxygen, which significantly enhances the oxidation stability of various polyether electrolyte systems. To demonstrate the feasibility of the ion-bridging strategy, a Zn<sup>2+</sup> ion-bridged polyether electrolyte (Zn-IBPE) with an extending electrochemical stability window of over 5 V is prepared, which enables good cyclability in 4.5 V Li||LiCoO<sub>2</sub> batteries. Ampere-hour-level quasi-solid-state batteries of SiO-graphite||LiNi<sub>0.8</sub>Mn<sub>0.1</sub>Co<sub>0.1</sub>O<sub>2</sub> (10 Ah, N/P ratio of 1.12, 303 Wh kg<sup>-1</sup> at 0.1 C based on the total weight of the pouch cells) and 60 μm-Li||LiNi<sub>0.9</sub>Mn<sub>0.05</sub>Co<sub>0.05</sub>O<sub>2</sub> (18 Ah, N/P ratio of 2.5, 452 Wh kg<sup>-1</sup> at 0.33 C based on the total weight of the pouch cells) pouch cells with Zn-IBPE present elevated electrochemical performance, benefiting from adequate interfacial stability. Nail penetration tests evidence high battery safety enabled by Zn-IBPE in 4 Ah graphite||LiNi<sub>0.8</sub>Mn<sub>0.1</sub>Co<sub>0.1</sub>O<sub>2</sub> pouch cells without combustion or smoke. This work offers a pathway for designing high-voltage polymer electrolytes and a general solution for achieving high-performance quasi-solid-state batteries.