中国科学院苏州纳米技术与纳米仿生研究所吴晓东团队，揭示了氟碳酸乙烯增强高性能室温钠硫电池的多功能机理。相关研究成果发表在2024年11月25日出版的国际学术期刊《德国应用化学》。

室温钠硫（RT-Na-S）电池在大规模储能技术中引起了越来越多的关注，但严重的穿梭效应和界面副反应限制了其实际应用。尽管氟代碳酸乙烯酯（FEC）已被广泛用作电解质添加剂或共溶剂，以促进RT-Na-S电池中电极-电解质界面的优化，但其关键影响和机制尚不清楚。

该文中，研究人员深入揭示了使用FEC作为唯一电解质溶剂形成阴极电解质界面（CEI）的两步过程。结果表明，FEC参与了快速亲核反应和阴极上的电化学分解，可以有效地原位构建由富含NaF的双层组成的独特的“巧克力饼干”形状的CEI。这种CEI消除了穿梭效应，并确保了硫的固-固转化。

除了在Na阳极上形成稳定的富F固体电解质界面（SEI）外，RT Na-S电池还具有令人印象深刻的性能（在0.5C下1000次循环后为456 mAh g^-1），库仑效率几乎为100%。这大大简化了电解质设计，并为FEC在实际Na-S电池中的应用提供了宝贵的见解。

附：英文原文

Title: Unraveling the Multifunctional Mechanism of Fluoroethylene Carbonate in Enhancing High-Performance Room-Temperature Sodium-Sulfur Batteries

Author: shixiao weng, Yang Liu, Suwan Lu, Jingjing Xu, Jiangyan Xue, Haifeng Tu, Zhicheng Wang, Lingwnag Liu, Yiwen Gao, Guochao Sun, Hong Li, Xiaodong Wu

Issue&Volume: 2024-11-25

Abstract: Room-temperature sodium-sulfur (RT Na-S) batteries has attracted growing attentions in large-scale energy storage technology, while the serious shuttle effect and interface side reaction limit its practical application. Despite fluoroethylene carbonate (FEC) has been widely used as an electrolyte additive or co-solvent to facilitate the optimization of electrode-electrolyte interphase in RT Na-S batteries, its crucial influence and mechanism have not been clearly understood. Herein, we deeply reveal the two-steps cathode-electrolyte interphase (CEI) formation by using FEC as the exclusive electrolyte solvent. The results demonstrate that FEC participates in both rapid nucleophilic reaction and electrochemical decomposition on cathode, which can effectively in situ construct a unique "chocolate-cookie" shaped CEI consisted of NaF-rich double layers. This CEI eliminates the shuttle effect and ensures the solid-solid conversion of sulfur. Along with the stable F-rich solid-electrolyte interphase (SEI) formed on the Na anode, the RT Na-S battery delivers an impressive performance (456 mAh g-1 after 1000 cycles at 0.5 C) with almost 100% Coulombic efficiency. This significantly simplifies electrolyte design and provides valuable insights into the application of FEC in practical Na-S batteries

DOI: 10.1002/anie.202421602

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202421602