Thermal runaway of Lithium-ion batteries employing LiN(SO2F)2-based concentrated electrolytes

Abstract

Concentrated electrolytes usually demonstrate good electrochemical performance and thermal stability, and are also supposed to be promising when it comes to improving the safety of lithium-ion batteries due to their low flammability. Here, we show that LiN(SO2F)2-based concentrated electrolytes are incapable of solving the safety issues of lithium-ion batteries. To illustrate, a mechanism based on battery material and characterizations reveals that the tremendous heat in lithium-ion batteries is released due to the reaction between the lithiated graphite and LiN(SO2F)2 triggered thermal runaway of batteries, even if the concentrated electrolyte is non-flammable or low-flammable. Generally, the flammability of an electrolyte represents its behaviors when oxidized by oxygen, while it is the electrolyte reduction that triggers the chain of exothermic reactions in a battery. Thus, this study lights the way to a deeper understanding of the thermal runaway mechanism in batteries as well as the design philosophy of electrolytes for safer lithium-ion batteries.

PEO based polymer-ceramic hybrid solid electrolytes: a review

“…Lithium ion batteries (LIBs) are widely used in phones, computers and other mobile devices owing to their high specific energy, good capability, good cycle performance and environmentally friendly property [1][2][3]. Although traditional carbonate based liquid electrolytes have high ionic conductivity under normal temperature, the organic solvent contained has the potential danger of leakage and combustion, which may cause severe safety issues.…”

Non‐Flammable Liquid and Quasi‐Solid Electrolytes toward Highly‐Safe Alkali Metal‐Based Batteries

“…According to the recent study, although the electrolytes are non‐flammable (i.e., possessing high resistance against oxidation by oxygen), their exothermic reduction reactions (e.g., the reduction of thermally stable lithium salts (e.g., LiFSI) by lithiated anodes) also trigger thermal runaway. [ 144 ] Therefore, synergistically improving the incombustibility of both electrodes and electrolytes, and simultaneously developing of highly‐sensitive detection methods (e.g., introducing microcalorimetry or optical fiber Bragg grating sensors [ 145 ] ) to operando monitor the battery thermal state should be the future development focus concerning battery safety.…”

Uncovering hydrogen anion triggered thermal runaway mechanism of a high-energy LiNi0.5Co0.2Mn0.3O2/graphite pouch cell

“…Conventionally, the thermal runaway mechanism of LIBs is demonstrated to be associated with a series of exothermic chain reactions, including decomposition of solid electrolyte interface (SEI) layer, anode/electrolyte reactions, self-decomposition of electrolyte, and cathode/electrolyte reactions, etc. [21][22][23][24][25] However, very recently, Prof. M. Ouyang et al revealed that the oxygen released from nickel-manganesecobalt (NMC) cathode will be consumed by the lithiated anode with great heat generation, triggering the thermal runaway of LIBs. 10 Differently, by analyzing the released gas, N. E. Galushkin et al propose that the powerful exothermic reaction from recombination of atomic hydrogen accumulated at anode graphite will contribute to the initiation of thermal runaway of LIBs.…”

“…But, both LiTFSI and LiFSI easily cause corrosion of Al current collector at high voltages exceeding 4 V. [33][34][35][36] Formulating high cost concentrated electrolyte will effectively prohibit LiFSI-induced Al corrosion, but, the LIB still undergoes thermal runaway due to the strong heat-releasing reaction between LiFSI salt and lithiated graphite. 23 Another economic way to suppress Al corrosion is to formulate blended-salt electrolytes by mixing LiTFSI or LiFSI with lithium di uoro(oxalate) borate (LiDFOB) or lithium bis(oxalato)borate (LiBOB). 9,28,36−43 Recently, blended-salt electrolytes showing synergistic effects have achieved great progress in the burgeoning eld of next-generation lithium batteries.…”