Improved Low-Temperature Performance of Li-Ion Battery of LiCoO₂//Graphite By Electrolyte Control

For the universal use of electric vehicle and energy storage system applications, Li-ion batteries are required to operate at low temperatures below –10 ○C. Battery performance at low temperatures is however often limited by electrolyte, mainly due to a lowered Li-ion conductivity and a phase change of high melting point component from liquid to solid. In an effort to overcome those drawbacks, researchers have made attempts on electrolyte development mostly by blending several solvents to ternary and quaternary electrolytes,1 and by using functional electrolyte additives.2 Although some improvements were made, challenges for finding new electrolyte component remains and the new electrolyte component has to be practically tested in the Li-ion batteries operated at low temperature. In this presentation, we report a development of new lithium salt as an additive to use in the conventional Li-ion cells of LiCoO2//graphite operated at –20 ○C. Improved low temperature performance by the effects of salt additive and its correlation to surface chemistry would be discussed in the meeting. Acknowledgements This research was supported by the Korean Ministry of Trade, Industry & Energy (A0022-00725 & R0004645). References 1. M. C. Smart, B. V. Ratnakumar, L. D. Whitcanack, K. B. Chin, S. Surampudi, H. Croft, D. Tice, R. Staniewicz, J. Power Sources, 119–121, 349 (2003). 2. L. Liao, X. Chenga, Y. Ma, P. Zuo, W. Fang, G. Yin, Y. Gao, Electrochim. Acta, 87, 466, (2013).