Construction of Cation-Conducting and Anion-Capture Solid Electrolyte Interphase for Highly Stable Sodium Metal Batteries.

Yi, Boqian; Wei, Zhixuan; Xia, Yangyang; Yao, Shiyu; Jiang, Heng; Sun, Ge; Chen, Nan; Zeng, Yi et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Sodium metal batteries are promising for grid-scale storage but suffer from dendrite growth due to anion-induced cation mobility limitations. To address this, we designed an artificial solid-electrolyte interphase (SEI) by grafting a fast Na<sup>+</sup> ion conductor, Na<sub>5</sub>GdSi<sub>4</sub>O<sub>12</sub>, with oxygen vacancies (NGSO-Vo), onto a glass fiber (GF) separator. This unique structure combines fast Na<sup>+</sup> conduction (8.55 mS cm<sup>-1</sup>) with anion immobilization, achieving a high Na<sup>+</sup> transference number (0.9) in a conventional NaClO<sub>4</sub>/PC electrolyte. The NGSO-Vo-modified GF exhibits exceptional mechanical stability, effectively suppressing dendrite growth. As a result, Na||Na symmetric cells achieve an ultrahigh current density (30 mA cm<sup>-2</sup>) and long-term cycling (1500 h at 20 mA cm<sup>-2</sup>). Moreover, Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>F<sub>3</sub>||Na pouch cells with high mass loading (24 mg cm<sup>-2</sup>) demonstrate a record stability (4000 h). This work presents a simple yet universal strategy to enhance Na-metal battery durability, paving the way for practical energy storage applications.