High-Safety Electrolytes for Lithium-Ion Batteries : Is non-flammability of electrolyte overrated in the overall safety performance of lithium ion batteries?

Technical Report · Thu Sep 01 04:00:00 EDT 2022

DOI:https://doi.org/10.2172/2202958· OSTI ID:2202958

Xu, Wu ^[1]; Jia, Hao ^[1]; Zhong, Lirong ^[1]; Cao, Xia ^[1]

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1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

It has been widely considered that the flammability of the liquid electrolyte is one of the most influential factors that determine the safety of lithium ion batteries (LIBs). Following this consideration, a completely non-flammable electrolyte was designed and adopted to graphite||LiFePO₄ (Gr||LFP) batteries. Contrary to the conventional understanding, the completely non-flammable electrolyte with phosphorus-containing solvents exhibits inferior safety performance in commercial Gr||LFP batteries, in comparison to the flammable conventional LiPF₆-organocarbonate electrolyte. Mechanistic studies identify the exothermic reactions between the electrolyte (especially the flame retarding phosphate solvent) and the charged electrodes as the “culprit” behind such a counterintuitive phenomenon. The discovery emphasizes the importance of reducing the electrolyte reactivity when designing safe electrolytes, as well as the necessity of evaluating safety performances of electrolyte on a battery level.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO); USDOE Office of Science (SC), Biological and Environmental Research (BER)
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 2202958
• Report Number(s): PNNL--33366
• Country of Publication: United States
• Language: English

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