Investigation into the Mechanism and Causes of Gassing in Li4Ti5O12 Based/ LiMn2O4 Li-Ion Battery Systems

Abstract

Li4Ti5O12 (LTO) as an anode material for lithium ion batteries has garnered attention as a possible alternative to graphite anodes in the hybrid and electric vehicle auto industry due to its increased safety properties, high rate capabilities, and exceptional cycling stability. The main concern arises in that cells using LTO anodes produce gas especially at elevated temperatures leading to swelling and hampered performance. Many mechanisms have been proposed as possible sources of the gas evolution such as breakdown of electrolyte salts, water, and LTO surface reactions, but no direct cause or solution has been agreed upon. In the open literature, efforts have been made to combat this with either coating on LTO materials2,4 or electrolyte technology without a full understanding of how the material behaves in the cell. In this work, we take the investigation further to pinpoint the causes and mechanisms of the gas evolution in LTO based cells through gas analysis, electrochemical performance, and surface analysis in multilayer pouch cells and full cell coin cells. These results will be discussed in detail with the intention of shedding light on the gas evolution issue with the hope of leading to optimized solutions to resolve the gassing issue. References Y. He, B. Li, M. Liu, C. Zhang, W. Lv, C. Yang, J. Li, H. Du, B. Zhang, Q. Yang, J. Kim, F. Kang, Sci. Rep. 2, 913 (2012).L. Wang, K. Nakura, M. Imazaki, N. Kakizaki, K. Ariyoshi, and T. Ohzuku, J. Electrochem. Soc., 159, A1710 (2012).J. Liu, P. Bian, J. Li, W. Ji, H. Hao, A. Yu, J. Pow. Sour., 286 (2015)W. Li, X. Li, M. Chen, Z. Xie, J. Zhang, S. Dong, M. Qu, Elect. Acta., 139 (2014)J. Gao, B.Gong, Q. Zhang, G. Wang, Y. Dai, W. Fan, Ionics, 21 (2015)J. Liu, P. Bian, J. Li, W. Ji, H. Hao, A. Yu, J. Pow. Sour., 286 (2015)