Nonflammable LiTFSI-Ethylene Carbonate/1,2-Dimethoxyethane Electrolyte for High-Safety Li-ion Batteries

Developing a nonflammable electrolyte is an efficient strategy to eliminate fire hazards and improve battery safety. Electrolytes containing nonflammable phosphate solvents enhance battery safety to a certain extent, but their compatibility with electrodes remains an obstacle. Here, a nonflammable electrolyte based on carbonate solvent is designed to resolve this dilemma while guaranteeing battery performance. We demonstrate that a nonflammable electrolyte employing the popular film-forming solvent ethylene carbonate (EC) and 1,2-dimethoxyethane (DME) with 2.3 mol kg −1 lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) has excellent thermal stability owing to the unique solution molecule structure. What’s more, the nonflammable electrolyte possesses excellent compatibility with both LiNi 0.6 Co 0.2 Mn 0.2 O 2 and graphite electrode. The initial specific capacity and capacity retention rate of graphite/LiNi 0.6 Co 0.2 Mn 0.2 O 2 punch cells employing this electrolyte are 169.3 mAh g −1 and 98.7% (after 50 cycles), respectively, which are comparable to those of cells employing traditional carbonate electrolytes. Besides, short-circuit test of the pouch cell suggests that the release of gases accompanied by decomposition of electrolyte under abuse conditions is effectively suppressed. All of these results show a promising prospect of this nonflammable electrolyte for application in high-safety Li-ion batteries.