Enhancing the High-Voltage Cycling Stability of Nickel-Rich Oxide Cathode Using Functional Electrolyte

Abstract

Increasing needs of electric vehicles and grid-based energy storage systems for the reduction of carbon dioxide gases require higher energy density lithium (Li)-ion batteries than commercial batteries. The energy density of Li-ion batteries can increase by increasing the specific capacity of cathode material, which can increase by raising the charge cut-off voltage. Among various cathode materials, nickel-rich layered oxides of Li(Ni1 –x –y Co x Mn y )O2 (NCM, 1–x–y ≥ 0.5) are promising high-capacity cathode materials for high-energy density Li-ion batteries because of higher capacity and lower cost than nickel-lean oxides. However, the limited anodic instability of the conventional carbonate-based organic electrolytes at the voltage higher than 4.2 V versus Li/Li+ and instability of cathode-electrolyte interface at highly charged state makes high-voltage charge of nickel-rich oxide cathode difficult. In order to mitigate the electrolyte and interface issues, we have been developing new functional electrolytes that provides high anodic stability above 4.3 V and highly stable cathode-electrolyte interface. High-voltage electrochemical and interfacial reaction studies and their correlation to cycling performance would be discussed in the meeting. Acknowledgements: This research was supported by Ministry of Trade, Industry & Energy (R0004645) and Creative Human Resource Development Consortium for Fusion Technology of Functional Chemical/Bio Materials of BK Plus program by Ministry of Education of Korea.