Ethyl acetate (EA) shows low viscosity for its relative permittivity. Monofluorinated organic solvents
exert the polar effect on the various properties. We have investigated the effect of position
isomerism on the physical and electrochemical properties of two monofluorinated carboxylates:
2-fluoroethyl acetate (2FEA) and ethyl fluoroacetate (EFA). Relative permittivity of 2FEA was lower
than that of EFA, whereas viscosity of 2FEA was higher. Electrolytic conductivity of a LiPF6 solution
in 2FEA was lower than that in EFA, but higher than that in EA at high temperatures. The use
of 2FEA as a co-solvent improved cycling efficiency and suppressed fading of discharge capacity of
a Li|LiCoO2 coin cell at high cycle numbers.
References
[1]
Riddick, J.A., Bunger, W.B. and Sakano, T.K. (1986) Organic Solvents: Physical Properties and Methods of Purification. 4th Edition, Wiley-Interscience, New York.
[2]
Yamaki, J. (2002) Advances in Lithium-Ion Batteries. In: van Schalkwijk, W.A. and Scrosati, B., Eds., Liquid Electro-Lytes, Chap. 5, Kluwer Academic/Plenum Publishers, New York, 155-183.
[3]
Aurbach, D. and Schechter, A. (2004) Lithium Batteries, Science and Technology. In: Nazri, G.-A. and Pistoia, G., Eds., Advanced Liquid Electrolyte Solutions, Chap. 18, Kluwer Academic Publishers, Boston, 530-573.
[4]
Ue, M. (2000) Richiumu-Ion Niji-Denchi, Zairyo To Oyo. 2nd Edition. In: Yoshio, M. and Kozawa, A., Eds., Yukidenkaieki No Yoekikagaku, Chap. 6, Nikkan Kogyo Shimbun Ltd., Tokyo, 83-98. (In Japanese)
[5]
Takehara, M., Tsukimori, N., Nanbu, N., Ue, M. and Sasaki, Y. (2003) Physical and Electrolytic Properties of Fluoroethyl Methyl Carbonate. Electrochemistry, 71, 1201-1204.
[6]
Nanbu, N., Takehara, M., Watanabe, S., Ue, M. and Sasaki, Y. (2007) Polar Effect of Successive Fluorination of Dimethyl Carbonate on Physical Properties. Bulletin of the Chemical Society of Japan, 80, 1302-1306. http://dx.doi.org/10.1246/bcsj.80.1302
[7]
Tsukimori, N., Nanbu, N., Takehara, M., Ue, M. and Sasaki, Y. (2008) Electrolytic Properties of Ethyl Fluoroethyl Carbonate and Its Application to Lithium Battery. Chemistry Letters, 37, 368-369. http://dx.doi.org/10.1246/cl.2008.368
[8]
Nanbu, N., Takimoto, K., Suzuki, K., Ohtake, M., Hagiyama, K., Takehara, M., Ue, M. and Sasaki, Y. (2008) Temperature Dependence of Physical Constants of Monofluororinated Propylene Carbonate as Highly Polar Liquid. Chemistry Letters, 37, 476-477. http://dx.doi.org/10.1246/cl.2008.476
[9]
Nanbu, N., Takimoto, K., Takehara, M., Ue, M. and Sasaki, Y. (2008) Electrochemical Properties of Fluoropropylene Carbonate and Its Application to Lithium-Ion Batteries. Electrochemistry Communications, 10, 783-786. http://dx.doi.org/10.1016/j.elecom.2008.02.031
[10]
Nanbu, N., Watanabe, S., Takehara, M., Ue, M. and Sasaki, Y. (2009) Electrolytic Characteristics of Fluoromethyl Methyl Carbonate for Lithium Rechargeable Batteries. Journal of Electroanalytical Chemistry, 625, 7-15. http://dx.doi.org/10.1016/j.jelechem.2008.09.022
[11]
Nambu, N., Nachi, T., Takehara, M., Ue, M. and Sasaki, Y. (2012) Structural Isomerism Effect on Physical and Electrochemical Properties of Monofluorinated Linear Carbonates. Electrochemistry, 80, 771-773. http://dx.doi.org/10.5796/electrochemistry.80.771
[12]
Nanbu, N., Suzuki, Y., Ohtsuki, K., Meguro, T., Takehara, M., Ue, M. and Sasaki, Y. (2010) Physical and Electrochemical Properties of Monofluorinated Ethyl Acetates for Lithium Rechargeable Batteries. Electrochemistry, 78, 446- 449. http://dx.doi.org/10.5796/electrochemistry.78.446
[13]
Nambu, N., Ohtsuki, K., Mutsuga, H., Suzuki, Y., Takehara, M., Ue, M. and Sasaki, Y. (2012) Use of Monofluorinated Ethyl Propionates as Solvents for Lithium Secondary Batteries. Electrochemistry, 80, 746-748. http://dx.doi.org/10.5796/electrochemistry.80.746
[14]
Nakajima, T., Dan, K., Koh, M., Ino, T. and Shimizu, T. (2001) Effect of Addition of Fluoroethers to Organic Solvents for Lithium Ion Secondary Batteries. Journal of Fluorine Chemistry, 111, 167-174. http://dx.doi.org/10.1016/S0022-1139(01)00449-3
[15]
Yamaki, J., Yamazaki, I., Egashira, M. and Okada, S. (2001) Thermal Studies of Fluorinated Ester as a Novel Candidate for Electrolyte Solvent of Lithium Metal Anode Rechargeable Cells. Journal of Power Sources, 102, 288-293. http://dx.doi.org/10.1016/S0378-7753(01)00805-9
[16]
Sato, K., Yamazaki, I., Okada, S. and Yamaki, J. (2002) Mixed Solvent Electrolytes Containing Fluorinated Carboxylic Acid Esters to Improve the Thermal Stability of Lithium Metal Anode Cells. Solid State Ionics, 148, 463-466. http://dx.doi.org/10.1016/S0167-2738(02)00088-7
[17]
Ihara, M., Hang, B.T., Sato, K., Egashira, M., Okada, S. and Yamaki, J. (2003) Properties of Carbon Anodes and Thermal Stability in LiPF6/Methyl Difluoroacetate Electrolyte. Journal of the Electrochemical Society, 150, A1476- A1483. http://dx.doi.org/10.1149/1.1614269
[18]
Kawamura, T., Tanaka, T., Egashira, M., Watanabe, I., Okada, S. and Yamaki, J. (2005) Methyl Difluoroacetate Inhibits Corrosion of Aluminum Cathode Current Collector for Lithium Ion Cells. Electrochemical Solid-State Letters, 8, A459-A463. http://dx.doi.org/10.1149/1.1993367
[19]
Koch, V.R. and Brummer, S.B. (1978) The Effect of Desiccants on the Cycling Efficiency of The Lithium Electrode in Propylene Carbonate-Based Electrolytes. Electrochimica Acta, 23, 55-62. http://dx.doi.org/10.1016/0013-4686(78)87033-9
[20]
Uneyama, K. (2006) Organofluorine Chemistry. Blackwell Publishing, Ltd., Oxford. http://dx.doi.org/10.1002/9780470988589
[21]
Andrade, E.N. da C. (1930) The Viscosity of Liquids. Nature, 125, 309-310. http://dx.doi.org/10.1038/125309b0
[22]
Aurbach, D. and Cohen, Y. (2004) Lithium-Ion Batteries. Solid-Electrolyte Interphase. In: Balbuena, P.B. and Wang, Y., Eds., Identification of Surface Films on Electrodes in Non-aqueous Electrolyte solutions: Spectroscopic, Electronic and Morphological Studies, Chap. 2, Imperial College Press, London, 70-139.
