瑞士联邦材料科学与技术研究所Ruben-Simon Kü课团队报道了离子液体在盐包水电解质中的水热效应。 相关研究成果发表在2021年3月31日出版的国际知名学术期刊《德国应用化学》。

盐包水电解质已成功地将水电解质的电化学稳定性窗口扩展到2V以上。通过用经典有机溶剂或离子液体部分取代水，可进一步提高稳定性。

该文中，研究人员研究了由LiTFSI、水和咪唑离子液体组成的三元电解质。研究发现，在离子液体存在条件下，LiTFSI在水中的溶解度从21mol/kg急速增加到60mol/kg。用拉曼光谱和核磁共振谱研究了溶液的结构，发现离子液体的水热效应导致了LiTFSI溶解度的提高。三元电解液的还原稳定性增强，使得水性锂离子电池能够在基于商业相关Li4Ti5O12和LiNi0.8Mn0.1Co0.1O2电极材料的活性材料水平上稳定循环，能量密度为150 Wh/kg。

附：英文原文

Title: The hydrotropic effect of ionic liquids in water‐in‐salt electrolytes

Author: Maximilian Becker, Daniel Rentsch, David Reber, Abdessalem Aribia, Corsin Battaglia, Ruben-Simon Kü

Issue&Volume: 2021-03-31

Abstract: Water‐in‐salt electrolytes have successfully expanded the electrochemical stability window of aqueous electrolytes beyond 2 V. Further improvements in stability can be achieved by partially substituting water with either classical organic solvents or ionic liquids. Here, we study ternary electrolytes composed of LiTFSI, water, and imidazolium ionic liquids. We find that the LiTFSI solubility strongly increases from 21 mol/kg in water to up to 60 mol/kg in the presence of ionic liquid. The solution structure is investigated with Raman and NMR spectroscopy and the enhanced LiTFSI solubility is found to originate from a hydrotropic effect of the ionic liquids. The increased reductive stability of the ternary electrolytes enables stable cycling of an aqueous lithium‐ion battery with an energy density of 150 Wh/kg on the active material level based on commercially relevant Li4Ti5O12 and LiNi0.8Mn0.1Co0.1O2 electrode materials.

DOI: 10.1002/anie.202103375

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202103375