High-Voltage Resistant Ionic Liquids for Lithium-Ion Batteries

• Published in: ACS applied materials & interfaces Vol. 12; no. 1; pp. 591 - 600
• Main Authors: Qi, Haojun, Ren, Yongyuan, Guo, Siyu, Wang, Yuyue, Li, Shujin, Hu, Yin, Yan, Feng
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 08-01-2020
• Subjects: ionic liquids; high voltage resistant; substitutions; lithium-ion battery; electron-donating
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.9b16786

With the growing demand for high energy and high power density rechargeable lithium-ion batteries, increasing research is focused on improving the output voltage of these batteries. Herein, a series of pyrrolidinium and piperidinium cations with various N-substituents (including cyanomethyl, benzyl, butyl, hexyl, and octyl groups) were synthesized and investigated with respect to their electrochemical stability under high voltages. The influence of substitutions at the N-position of pyrrolidinium and piperidinium cations on their high-voltage resistance was studied by both theoretical and experimental approaches. The voltage resistance was enhanced as the electron-donating ability of the substitutes increased. Furthermore, 1-hexyl-1-methylpyrrolidinium bis­(trifluoromethylsulfonyl) imide ([C6Py]­[TFSI]) exhibited the highest decomposition voltage at approximately 5.12 V and showed promising potential in a lithium-ion battery.