Room temperature molten salts as lithium battery electrolyte

• Published in: Electrochimica acta 2004-10, Vol.49 (26), p.4583-4588
• Main Authors: Garcia, Béatrice, Lavallée, Serge, Perron, Gérald, Michot, Christophe, Armand, Michel
• Format: Article
• Language: English
• Subjects: Applied sciences; Bis-(trifluoromethanesulfonyl)-imide; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrolyte; Ethyl-methyl-imidazolium; Exact sciences and technology; Ionic liquids; Lithium battery
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2004.04.041

In the present study, are reported investigations obtained with the room temperature molten salt (RTMS) ethyl-methyl-imidazolium bis-(trifluoromethanesulfonyl)-imide (EMI-TFSI) in order to use it as solvent in lithium battery. The thermal stability, viscosity, conductivity and electrochemical properties are presented. A solution of 1m lithium bis-(trifluoromethanesulfonyl)-imide (LiTFSI) in EMI-TFSI has been used to test the electrolyte in a battery with LiCoO 2 and Li 4Ti 5O 12 as respectively cathode and anode materials. Cycling and power measurements have been obtained. The results have been compared with those obtained with a molten salt formulated with a different anion, BF 4 − and with a conventional liquid organic solvent EC/DMC containing LiTFSI. The 1m LiTFSI/EMI-TFSI electrolyte provides the best cycling performance: a capacity up to 106 mAh g −1 is still delivered after 200 cycles, with 1 C rate at 25 °C.