Improvement of High Voltage Cycling Performance of Lithium-Ion Cells By Employing a Functional Additive

Abstract

Lithium-ion batteries (LIBs) are being widely used in many applications such as mobile electronic devices, electric vehicles and energy storage systems because of their high energy density and excellent cycle life. As there is always need for increasing the battery capacity, high voltage operating is essential. However, there are several issues in high voltage operation of LIBs; dissolution of transition metal from the active cathode material and oxidative decomposition of liquid electrolyte. Among the strategies for improving the high-voltage cycling performance, an addition of functional additive is one of the most promising methods. Functional additives can form cathode electrolyte interphase (CEI) on the cathode surface during cycling, which suppress the oxidative electrolyte decomposition and the dissolution of transition metal from cathode. In our study, we investigated effective additives for forming the uniform CEI layer and applied them to the LIB composed of graphite anode and NCM cathode. Electrochemical characterization and performance evaluation were performed to examine how these additives could improve the high-voltage cycling performance of LIBs.