Reduction Products of Vinylene Carbonate and Fluoroethylene Carbonate

Lithium ion batteries play an important role as energy storage devices in consumer electronics and electric vehicles, thanks to their high energy density, high efficiency and long life. Mixtures of organic carbonates are usually employed as electrolyte solvents in these batteries. Electrolyte reacts reductively with the anode and forms a passivation layer (SEI) during initial charging cycles. SEI layer plays a crucial role in the performance of a lithium-ion battery1 and small amount of additives are generally employed to improve the characteristics of the SEI. Understanding the reduction products of effective electrolyte additives would facilitate us to design better additives to improve the performance of lithium ion battery. Vinylene carbonate and fluoroethylene carbonate are excellent additives. They improve the initial irreversible capacity and high temperature performance of the lithium-ion battery, when added to the electrolyte.2 , 3 Theoretical study on reduction of these additives indicates, they may yield very similar SEI.4 Lithium naphthalenide, a popular one-electron reducing agent, is shown to reduce the electrolyte similar to lithiated graphite anode.5 The same compound is utilized to reduce Vinylene carbonate & fluoroethylene carbonate. The products were analyzed with GCMS, NMR & FTIR and the results will be discussed. Acknowledgement The authors gratefully acknowledge funding from Department of Energy Office of Basic Energy Sciences EPSCoR Implementation award (DE-SC0007074). References (1) R Fong, U von Sacken, J. D. 2009, 137 (7), 3–7. (2) Aurbach, D.; Gamolsky, K.; Markovsky, B.; Gofer, Y.; Schmidt, M.; Heider, U. Electrochim. Acta 2002, 47 (9), 1423–1439. (3) McMillan, R.; Slegr, H.; Shu, Z. .; Wang, W. J. Power Sources 1999, 81-82, 20–26. (4) Hoz, J. D. La; Balbuena, P. Phys. Chem. Chem. Phys. 2014, 1–18. (5) Nie, M.; Chalasani, D.; Abraham, D. P.; Chen, Y.; Bose, A.; Lucht, B. L. J. Phys. Chem. C 2013, 117 (3), 1257–1267.