高氯酸锂-乙酰胺新型二元熔盐电解质的谱学研究

Spectroscopic Investigation of New Binary Molten Salt Electrolytes Based on Li ClO_4 with Acetamide

高氯酸锂与乙酰胺在适宜摩尔配比范围内可形成热稳定性良好、电化学性能优良的室温熔盐.从分析LiClO4与乙酰胺形成熔盐的作用机制出发,通过红外、拉曼光谱的谱学分析并应用非局部密度泛函理论方法进行量化计算对二者的相互作用进行了讨论.发现乙酰胺通过Li-O键与LiClO4中的Li+配位而破坏了LiClO4的离子键,形成很大的配位阳离子,削弱了阴阳离子间的库伦作用力;同时Li-O也导致乙酰胺分子间的氢键断裂,因而体系的共熔温度较之纯物质熔点显著降低,部分样品室温下以液体状态稳定存在.

New low-temperature molten salt electrolytes based on LiClO4 and acetamide with proper molar ratio appear as liquid at room temperature through they are composed of two solids and have excellent thermal stability and electrochemical properties. The mechanism of action has been studied by FT-IR spectroscopy, FT-Raman spectroscopy and quantum chemistry calculation with nonlocal DFT. The results indicated that acetamide can coordinate with Li+ cation in the LiClO4-acetamide system through Li-O bonding. A big coordinate cation was formed and the coulombic force was weakened. Meanwhile, Li - O can also lead to the breakage of hydrogen bonding between acetamide molecules, resulting in the decrease of the co-molten temperature of the system compared with that of pure salt. A part of samples of this molten salt could exist stably in liquid state at room temperature.