Influence of crucible material on the thermal stability analysis of ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

Recently, ionic liquid [Bmim][NTf2] was found to be used as an electrolyte for planar thin film supercapacitors. In such applications, the thermal stability in air atmosphere is a critical characteristic that should be thoroughly evaluated. Moreover, the materials of crucibles used for assessing the thermal stability of ionic liquids are very diverse in the literature. In fact, to date, there is a lack of studies in the literature regarding the effect of crucible materials on the TGA/DSC results of ionic liquids. In this study, the influence of crucible materials on TGA/DSC analyses of ionic liquid [Bmim][NTf2] in air atmosphere is investigated. The results show that TGA curves obtained with alumina, platinum, and aluminum crucibles are different. A non-uniform black residue was observed in the center of the aluminum crucible, and it is believed that another reaction between the ionic liquid [Bmim][NTf2] with the aluminum crucible exists, rather than the original decomposition reaction being catalyzed by the aluminum crucible. In the DSC analysis, the heat effect obtained in the platinum crucible is much higher than that obtained in the alumina or aluminum crucible. When using a platinum crucible, the decomposition reaction occurs at a lower temperature, and the reaction rate is faster at the same temperature than the crucible with the other two materials. Therefore, it is recommended that when using the TGA/DSC method to evaluate the thermal stability of ionic liquids [Bmim][NTf2] in air atmosphere, the material effect of the container in actual application should be carefully considered.