A novel electrolyte additive for improving the stability of layered oxide cathode material-based lithium-ion batteries under high temperature and voltage conditions

Abstract

In this study, a new electrolyte additive, 3-triethoxysilylpropylsuccinic acid anhydride (TAA), for lithium-ion batteries is reported. The additive is introduced as a novel electrolyte additive to remove water and hydrogen fluoride (HF), as well as enhance the electrochemical performance of layered lithium nickel cobalt manganese oxide (NCM) and lithium cobalt oxide (LiCoO₂) cathodes containing a Li₅FeO₄ additive under higher working voltage conditions. Encouragingly, the protective films could be formed on the cathode and anode surfaces by the electrochemical oxidation or reduction, and the stability of the solid electrolyte interface (CEI) of the cathode and the solid electrolyte interface (SEI) of the anode could be greatly improved. By adding 0.5 wt% of TAA into the electrolyte, the battery exhibited outstanding properties. The thickness swelling decreased from 60% to about 23% after 8 h storage at 85 °C. In addition, the capacity retention of the battery at 45 °C increased 4% by adding TAA after 550 cycles under 4.5 V. Because of its specific function, the additive can be used in high energy density and high voltage lithium-ion battery systems.