Design of Non‐Incendive High‐Voltage Liquid Electrolyte Formulation for Safe Lithium‐Ion Batteries

• Published in: ChemSusChem 2022-02, Vol.15 (4), p.e202102546-n/a
• Main Authors: Kwak, Sehyun, An, Kihun, Tran, Yen Hai Thi, Song, Seung‐Wan
• Format: Article
• Language: English
• Subjects: battery safety; Electric potential; Electric vehicles; Electrolytes; Energy storage; Flammability; high-voltage; Interface stability; Lithium; Lithium-ion batteries; Organic liquids; Product safety; Storage batteries; Thermal runaway; Thermal stability; Voltage
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202102546

Battery safety has an ever‐increasing significance and is required for consumer's safety. The high flammability of traditional organic liquid electrolyte, which consists of ethylene carbonate and highly flammable linear carbonate, is one of the major reasons for thermal runaway and battery fire events. Replacement of flammable liquid electrolyte with non‐incendive one is urgently needed for safe lithium‐ion batteries. A fluorinated linear sulfate paired with 1 m LiPF6 was developed and evaluated as a solvent of non‐incendive liquid electrolyte for a use in high‐voltage (4.4 V) and high‐temperature (45 °C) LiNi0.82Mn0.07Co0.11O2 (NCM811) chemistry‐based lithium‐ion batteries. Non‐incendive liquid electrolyte containing sulfate with two trifluoroethyl groups exhibited superior anodic and thermal stability and promoted cathode–electrolyte and anode‐electrolyte interfacial stability, compared to flammable traditional electrolyte. Non‐incendive electrolyte showed markedly improved 300 cycle performance of an industrial graphite‖NCM811 lithium‐ion pouch cell with a nominal capacity of 730 mAh under harsh conditions, and high safety of 10 V overcharge abuse tolerance, from which safe and high‐performing high‐energy lithium‐ion batteries and battery‐powered electric vehicles and energy storage system are anticipated. We didn't start the fire: A new, non‐incendive liquid electrolyte formulation containing fluorinated linear sulfate and the electrolyte‐derived solid‐electrolyte interphase stabilization yield a safe and high‐performing Li‐ion battery operated under high voltage and temperature, from which safe and longer‐range electric vehicles and energy storage systems are anticipated.