Defect-Rich g-C<sub>3</sub>N<sub>4</sub> Nanosheets Catalyze PEO-Based Electrolytes to Create Fluorine-Rich Interfaces for High-Rate All-Solid-State Lithium-Metal Batteries.

Zhou, Xuan; Xu, Guobao; Huang, Ke; Yan, Zhihao; Hu, Huan; Li, Xue; Wang, Gang; Jiang, Wenjuan et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Although poly(ethylene oxide) (PEO) based electrolytes have attracted significant interest in all-solid-state lithium-metal batteries, the inferior ionic conductivity and poor interfacial incompatibility with lithium-metal have limited their practical application. Herein, nitrogen-defect-abundant g-C<sub>3</sub>N<sub>4</sub> (V<sub>N</sub>-CN) nanosheets are introduced into PEO to form composite solid electrolytes (V<sub>N</sub>-CN-PEO). The rich defects act as "electron traps" that effectively weaken Li<sup>+</sup> coordination with the anions and facilitate the decomposition of lithium salt, thus forming a LiF-rich interface with the Li anode. Therefore, the V<sub>N</sub>-CN-PEO exhibits reduced interfacial resistance with electrodes, improved Li<sup>+</sup> conductivity, and high mechanical strength. As a result, the Li symmetrical cells exhibit ultralong plating/stripping cycling for 3600 h at 0.1 mA cm<sup>-2</sup>. The Li/V<sub>N</sub>-CN-PEO/LiFePO<sub>4</sub> cells deliver a capacity retention of 90% after 300 cycles at 0.2 C under 30 °C. Even the pouch cells show 81% capacity retention after 300 cycles at 0.1 C under 60 °C.