Effect of 1-butyl-1-methylpyrrolidinium hexafluorophosphate as a flame-retarding additive on the cycling performance and thermal properties of lithium-ion batteries

► 1-Butyl-1-methylpyrrolidinium hexafluorophosphate was used as a flame-retarding additive. ► An addition of BMP-PF6 suppressed the flammability and improved the thermal stability. ► The optimum BMP-PF6 content in the electrolyte was found to be 10 wt.%.