EC‐Less Electrolytes for High‐Safety and Long‐Life Nickel‐Rich Lithium‐Ion Batteries

Abstract High‐nickel lithium‐ion batteries are known for their high energy density, but face severe safety challenges. The initial heat and gas accumulation originate from the highly reductive lithiated anode at the anode‐electrolyte interface within the cell, which finally triggers the intensive exothermic reactions. Herein, an ethylene carbonate‐less (EC‐less) electrolyte endowed with a bianionic coordination solvation structure is designed, which significantly enhances the thermal stability of LiNi0.8Co0.1Mn0.1O2|graphite (NCM811|Gr) pouch cells by mediating anode‐electrolyte interfacial reactions. This bianionic structured EC‐less electrolyte demonstrates superior reductive stability against the highly reactive lithiated anode, as evidenced by its elevated lowest unoccupied molecular orbital (LUMO) energy level. Material‐level thermal analysis confirms that EC‐less electrolyte markedly manipulates the electrolyte reduction reactions, achieving a 29.7% reduction in heat release (−225.5 J g −1 ) relative to conventional electrolyte (−320.8 J g −1 ). Further validation using 1 Ah NCM811|Gr pouch cells demonstrates that EC‐less electrolyte enables the cell to maintain thermal inertness at 180 °C for 40 min, whereas a conventional cell experiences intensive thermal runaway at 160 °C. Furthermore, EC‐less electrolyte facilitates the formation of an inorganic‐rich interphase, and the pouch cell exhibits excellent electrochemical performance. This research highlights the potential of interfacial reaction engineering for safer high‐nickel lithium batteries.