<p>In this study, the flash points and ionic conductivity of three ternary electrolyte solvents (ethylene carbonate (EC); diethyl carbonate (DEC); and dimethyl carbonate (DMC)) were investigated in lithium-ion batteries. The flash points of the solvent mixtures were experimentally measured and compared with predictions using Raoult’s law and multiple regression analysis. These results indicate that EC increases flash point temperature and ionic conductivity owing to its high dielectric constant and boiling point. In contrast, DMC has a lower flash point because of its low boiling point and high reactivity. The coefficient of determination (<i>R</i>²) and mean absolute error (MAE) suggest that Raoult’s law better predicts overall trends in flash points. Simultaneously, multiple regression analysis provided higher accuracy for specific mixture compositions. Additionally, the ionic conductivities of the ternary electrolyte mixtures were analyzed, demonstrating that DMC maintained high conductivity through polar conformers despite its low dielectric constant. The optimal mixture ratio of EC: DEC: DMC at 7:2:1 achieved a balance with a high flash point (55.5&#xa0;°C) and high ionic conductivity (9.0 mS cm⁻¹), enhancing battery safety and ionic conductivity. This study highlights the critical role of solvent composition in optimizing lithium-ion battery electrolytes for improved safety and ionic conductivity.</p> Graphical Abstract <p></p>