Preventing thermal runaway of high-nickel Li-ion battery through nonflammable carbonates-based electrolyte formulation

Abstract

The safety of lithium-ion batteries (LIBs) is essential for the secured safety of consumers, whose demand is therefore never-ending. The risk of LIBs thermal runaway (TR) and fire is one of the concerns that hinders the market expansion of high nickel LIB-powered electric vehicles and e-mobilities. A primary cause of TR is the significant flammability of traditional organic liquid electrolyte that includes highly flammable linear carbonate solvent. Replacing traditional flammable liquid electrolyte with a well-formulated nonflammable liquid one, along with construction of both a thermally durable solid electrolyte interphase (SEI) on anode and cathode electrolyte interphase (CEI) on cathode, is a promising first step in mitigating TR issue. Herein, we demonstrate for the first time that the nonflammable fluorinated carbonates and standard lithium salt concentration (1.0 M)-based liquid electrolyte formulation with promoted Li⁺ transference number enables the prevention of TR of industrial 800 mAh graphite//LiNi_0.8Co_0.1Mn_0.1O₂(NCM811) pouch cell and outstanding 600 cycles performance at 1 C delivering 81 % capacity retention, without Li dendrites. Nonflammable electrolyte-derived robust SEI and CEI layers contribute to the prevention of TR and metal-dissolution from cathode. The formulation technology of nonflammable liquid electrolytes offers new opportunities to solve the safety issues associated with LIBs, holding promise for next-phase energy storage solutions.