温州大学侴术雷团队报道了高性能钠金属电池弱配位稀释剂调制溶剂化化学。相关研究成果发表在2024年3月15日出版的《德国应用化学》。

稀释剂已被广泛用于克服高浓度电解质的高粘度和缓慢动力学的缺点，但通常不会改变原始的溶剂化结构。

该文应用弱配位稀释剂六氟异丙基甲基醚（HFME）来调节Na⁺与二甘醇和阴离子的配位，形成稀释剂参与的溶剂合物。这种独特的溶剂化结构通过构建坚固的富含无机物的电极电解质界面，促进阴离子和稀释剂的加速分解。

此外，HFME的引入降低了Na⁺的脱溶能，提高了离子导电性，增强了抗氧化剂，提高了电解质的安全性。结果，组装的Na||Na对称电池实现了超过1800小时的稳定循环。Na||P’2-Na_0.67MnO₂电池在350次循环后，提供了87.3%的高容量保持率和99.7%的高平均库仑效率。

该项工作为高级电解质工程提供了对溶剂化化学的宝贵见解。

附：英文原文

Title: Weakly Coordinating Diluent Modulated Solvation Chemistry for High-Performance Sodium Metal Batteries

Author: Jiaxin Li, Simi Sui, Xunzhu Zhou, Kaixiang Lei, Qian Yang, Shenxu Chu, Lin Li, Yuqing Zhao, Mengjia Gu, Shulei Chou, Shijian Zheng

Issue&Volume: 2024-03-15

Abstract: Diluents have been extensively employed to overcome the disadvantages of high viscosity and sluggish kinetics of high-concentration electrolytes, but generally do not change the pristine solvation structure. Herein, a weakly coordinating diluent, hexafluoroisopropyl methyl ether (HFME), is applied to regulate the coordination of Na+ with diglyme and anion and form a diluent-participated solvate. This unique solvation structure promotes the accelerated decomposition of anions and diluents, with the construction of robust inorganic-rich electrode-electrolyte interphases. In addition, the introduction of HFME reduces the desolvation energy of Na+, improves ionic conductivity, strengthens the antioxidant, and enhances the safety of the electrolyte. As a result, the assembled Na||Na symmetric cell achieves a stable cycle of over 1800 h. The cell of Na||P’2-Na0.67MnO2 delivers a high capacity retention of 87.3% with a high average Coulombic efficiency of 99.7% after 350 cycles. This work provides valuable insights into solvation chemistry for advanced electrolyte engineering.

DOI: 10.1002/anie.202400406

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202400406