Investigation of Ethylene Carbonate Free Electrolyte for L_4Ti_5O_(12) Vs LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2 Multi-Layer Pouch Cells

摘要

Lithium titanate (L_4Ti_5O_(12) or LTO) is a sought-after alternative in conjunction with high voltage capable cathodes to the graphite anode in lithium ion batteries for electric vehicle and stationary storage applications. LTO offers improved abuse tolerance due to elimination of lithium dendrite formation when compared to graphite, the zero-strain property which enables operation at high rates, wide operating temperature range, and long cycle life. The limitations of LTO include a low specific capacity that of which is half the capacity of graphite anode, significant gas generation, and a high working potential (1.55V vs Li~0/Li~+). LTO pairing with various Li[Ni_xMn_yCo_(1-xy)]O_2 (NMC) materials appears interesting as it may offer improvements to the low specific capacity of the LTO material, when compared to cathode materials such as LMO or LCO~2 without the complexities and numerous challenges still associated with spinel cathode materials. Herein we report on an electrolyte optimization study for the LiNi_(0.6)Mn_(0.2)Co_(0.2)O_2 (NCM622)//LTO electrode couple using multi-layer pouch cells, which focuses on ethylene carbonate (EC) free formulations, with the aim of reducing the amount of gas formed by the LTO anodes.