什么是“离子液体”？

离子液体是一类结构可设计，性能多样化的一类新型物质统称，应用领域广泛，用作：催化剂、吸收剂、萃取剂、阻燃剂、抗静电剂、导电助剂、润滑剂、杀菌剂，涉及领域：化工、医药、材料、半导体、生物、芯片、航天、显示、环保、通讯、润滑等... 目前已见报道的离子液体根据分子结构和物化性质可分化四代。第一代离子液体主要的组分是作为阳离子的二烷基咪唑六氟磷酸盐/烷基吡啶六氟磷酸盐和作为阴离子的金属卤化物，他们是理想的电化学溶剂，然而对空气和水非常敏感。第二代离子液体由铵盐等作为常用的阳离子，而六氟磷酸盐等作为阴离子，从而可在空气和水中稳定。第三代离子液体则包括了氨基酸和胆碱等天然离子或者是具有生物活性的离子。而第四代则最早出现在2018年，他们与其他分子液体混合后或者溶解后可展现出独特的性能。 图1离子液体中典型的阳离子和阴离子

Room-temperature ionic liquids are, as the name suggests, salts that exist in liquid states at room temperature. RTILs are of great interest to a variety of fields because they exhibit unique physical and thermodynamic properties, such as negligble vapor pressure, high thermal stability, high electrochemical stability, and low flammability. Moreover, ionic liquids exhibit high conductivity and a wide electrochemical window, which means that they are neither easily oxidized nor reduced, hence they are excellent candidates for efficient and green electrolytes in batteries. Due to the various potential applications RTILs promise, computer simulations of RTILs have widely propagated, and various combinations of different cations and anions have been designed and tested to further increase our knowledge in this field. Please note: this tutorial uses the general Amber force field (GAFF) force field to create an initial (not a “refined”) force field. Some aspects of the simulation results are not in as good agreement with experiment as the results presented in the papers listed above. This is a good object lesson: GAFF can get you started, and can provide results of reasonable accuracy. Depending on your needs, this may be enough. But it is often desirable to treat the GAFF results as a starting point for further refinement; the latter is usually system-specific, and is not covered in this tutorial.