法拉第效率
二聚体
电解质
材料科学
溶剂化
稀释剂
化学工程
剥离(纤维)
无机化学
化学
溶剂
核化学
有机化学
物理化学
电极
复合材料
工程类
作者
Liang Hu,Jiaojiao Deng,Yuxiao Lin,Qinghua Liang,Bingcheng Ge,Qingsong Weng,Yu Bai,Yunsong Li,Yonghong Deng,Guohua Chen,Xiaoliang Yu
标识
DOI:10.1002/adma.202312161
摘要
Abstract The reversible and durable operation of sodium metal batteries at low temperatures (LT) is essential for cold‐climate applications but is plagued by dendritic Na plating and unstable solid‐electrolyte interphase (SEI). Current Coulombic efficiencies of sodium plating/stripping at LT fall far below 99.9%, representing a significant performance gap yet to be filled. Here, the solvation structure of the conventional 1 m NaPF 6 in diglyme electrolyte by facile cyclic ether (1,3‐dioxolane, DOL) dilution is efficiently reconfigured. DOL diluents help shield the Na + ‐PF 6 − Coulombic interaction and intermolecular forces of diglyme, leading to anomalously high Na + ‐ion conductivity. Besides, DOL participates in the solvation sheath and weakens the chelation of Na + by diglyme for facilitated desolvation. More importantly, it promotes concentrated electron cloud distribution around PF 6 − in the solvates and promotes their preferential decomposition. A desired inorganic‐rich SEI is generated with compositional uniformity, high ionic conductivity, and high Young's modulus. Consequently, a record‐high Coulombic efficiency over 99.9% is achieved at an ultralow temperature of −55 °C, and a 1 Ah capacity pouch cell of initial anode‐free sodium metal battery retains 95% of the first discharge capacity over 100 cycles at −25 °C. This study thus provides new insights for formulating electrolytes toward increased Na reversibility at LT.
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