A Glycerol Triacetate based Flame Retardant High-Temperature Electrolyte for The Lithium-Ion Battery

Rechargeable batteries that can operate at elevated temperatures (&gt;70 °C) with high energy density are long-awaited for industrial applications including mining, grid stabilization, naval, aerospace, and medical devices¹. However, the safety, cycle life, energy density and cost of the available high-temperature battery technologies remain an obstacle primarily owing to the limited electrolyte options available². Here, we demonstrated a flame-retardant electrolyte that can enable stable battery cycling at 100 °C by incorporating triacetin into the electrolyte system. Triacetin has excellent chemical stability with lithium metal and conventional cathode materials can effectively reduce parasitic reactions and promises a good battery performance at elevated temperatures. Our findings reveal that Li-metal half-cells can be made that have high energy density, high coulombic efficiency, and good cycle life with triacetin-based electrolytes and three different cathode chemistries. The high-temperature failure mechanism of different cathode chemistries was also investigated and compared. Moreover, the nail penetration test in a commercial-scale pouch battery using triacetin-based electrolyte system demonstrated suppressed heat generation when the cell was damaged and excellent safety when using the triacetin-based electrolyte. These results demonstrated a new low-cost high-temperature flame-retardant electrolyte candidate which holds significant importance in developing a more robust electrolyte system for high-temperature secondary battery applications.<br/><br/><br/><br/>[1] Chen, T.; Jin, Z.; Liu, Y.; Zhang, X.; Wu, H.; Li, M.; Feng, W. W.; Zhang, Q.; Wang, C. <i>Angewandte Chemie - International Edition</i> <b>2022</b>, <i>61</i> (35).<br/>[2] Ren, D.; Feng, X.; Liu, L.; Hsu, H.; Lu, L.; Wang, L.; He, X.; Ouyang, M. <i>Energy Storage Mater</i> <b>2021</b>, <i>34</i>.