(上海交通大學(xué) 化學(xué)化工學(xué)院，上海 200240)
摘 要: 采用循環(huán)伏安、恒電流充放電、X射線衍射、掃描電鏡技術(shù)研究含有三氟甲基磺酸鎂的1−乙基−3−甲基咪唑四氟硼酸鹽、1−丁基−3−甲基咪唑四氟硼酸鹽、1−丁基−2，3−二甲基咪唑四氟硼酸鹽、1−丁基−2,3−二甲基咪唑鎓雙三氟甲基磺酰亞胺鹽4種離子液體中鎂的沉積與溶出行為以及沉積物的組成和形貌。結(jié)果表明：在咪唑陽離子基團中增加1−位碳上烷基鏈的長度和在2−位碳上引入甲基可以提高咪唑陽離子的還原穩(wěn)定性，拓寬電解液還原電位窗口到−1 V (vs Mg RE)；同時采用TFSI−陰離子可使電解液陽極氧化電位拓寬到3.1 V (vs Mg RE)以上；適量添加有機溶劑THF可增加Mg2+的還原−氧化峰電流，降低峰電位差，提高可逆性。
關(guān)鍵字: 離子液體；鎂；沉積−溶出；可逆性
（School of Chemistry and Chemical Technology, Shanghai Jiaotong University, Shanghai 200240）
Abstract:The deposition-dissolution performance of magnesium in four imidazolium-based ionic liquids, 1-ethyl-3- methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, 1-butyl-2,3-dimethylimidazolium bis((trifluoromethyl)sulfonyl)imide containing Mg(CF3SO3)2 used as the electrolytes was studied by cyclic voltammogramms and constant current discharge-charge techniques. X-ray diffraction and scanning electron microscope measurements were conducted to characterize the components and morphologies of deposits. The results show that the cathodic satiability of imidazolium cations can be improved by increasing the length of alkyls at the first position and introducing methyl group at the second position of the imidazolium cations, and the cathodic limit of the electrolytes can be widen to −1 V (vs Mg RE). The anodic limit of the electrolyte with TFSI− anion can reach to 3.1 V (vs Mg RE). After adding appreciate amount of THF organic solvent, the peak currents and reversibility of Mg2+ reduction-oxidation can be improved.
Key words: ionic liquids; magnesium; deposition−dissolution; reversibility
