Ionic liquid electrolytes for lithium batteries: Synthesis, electrochemical, and cytotoxicity studies

• Published in: Journal of power sources Vol. 234; pp. 277 - 284
• Main Authors: Madria, Ninu, Arunkumar, T.A., Nair, Nanditha G., Vadapalli, Avinash, Huang, Yue-Wern, Jones, Simon C., Reddy, V. Prakash
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.07.2013; Elsevier
• Subjects: Applied sciences; Cytotoxicity; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical stability; Exact sciences and technology; Imidazolium; Lithium batteries; Nonaqueous electrolytes; Pyrrolidinium; Nonaqueous electrolytes; Imidazolium; Lithium batteries; Cytotoxicity; Pyrrolidinium; Electrochemical stability; Organic cation; Alkaline storage battery; Secondary cell; Ionic liquid; Lithium battery; Electrolyte; Chemical synthesis; Non aqueous solvent
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.02.002

We have synthesized and determined the electrochemical and thermal stabilities of a series of 1-methyl-3-alkoxyalkyl and 1-methyl-3-fluoroalkyl imidazolium and the corresponding pyrrolidinium-based ionic liquids and estimated the cytotoxicities of representative ionic liquids. The pyrrolidinium-TFSI based ionic liquids have wide electrochemical stability (>5.7–6.2V vs. Li/Li+) but show limited thermal stabilities and lithium cell discharge characteristics, as compared to those that are imidazolium-based (4.8–5.1V vs. Li/Li+). The fluoroalkyl-derived ionic liquids typically have superior thermal stability (Td>350°C) as compared to the alkoxyalkyl-substituted analogues. In all these cases, TFSI− anion-based ionic liquids are thermally and electrochemically more stable than the BF4− anion-based analogues. We have also shown that the imidazolium-based ionic liquids are relatively nontoxic and their EC50 values are comparable to their corresponding lithium salts. ► Ionic liquids are evaluated as potential electrolytes for Li/CFx primary batteries. ► High discharge capacities and wide electrochemical windows are demonstrated. ► The studied ionic liquid electrolytes are relatively nontoxic to human health.