Thermal hazard evaluation and risk assessment of 1-allyl-3-methylimidazole nitrate ionic liquid

Imidazole ionic liquids (ILs) have broad application prospects in batteries and other fields. Researching the thermal decomposition features of ILs holds paramount importance for the application in battery electrolyte. 1-allyl-3-methylimidazole nitrate ionic liquid (IL) as a new functional IL, and its related thermal decomposition properties are unknown. In this paper, the thermal decomposition peculiarities of 1-allyl-3-methylimidazole nitrate IL were systematically analyzed by thermogravimetric analyzer, differential scanning calorimetry, and accelerating rate calorimeter techniques, and the relevant thermodynamic parameters and thermal decomposition models were derived. In addition, 1-allyl-3-methylimidazole nitrate IL possesses strong thermal runaway characteristics and the risk of thermal runaway is also evaluated. The main gaseous products formed by the pyrolysis of 1-allyl-3-methylimidazole nitrate IL was detected and analyzed by thermogravimetry-Fourier transform infrared spectroscopy and thermogravimetric-photoionization mass spectrometry techniques. The results showed that flammable gas, toxic gas, and asphyxiating gas are formed during the pyrolysis of 1-allyl-3-methylimidazole nitrate IL. This study lays a theoretical foundation for the safe application and the formulation of corresponding safety protection measures of 1-allyl-3-methylimidazole nitrate IL.