(Invited) Insight into Interfacial Processes between Lithium-Rich Layered Oxide Cathode and High-Voltage Electrolyte

摘要

Lithium-rich layered oxide, xLi_2MnO_3·(1-x)LiMO_2 (M = Mn/Ni/Co), is a promising high-capacity cathode active material for high-energy density rechargeable lithium batteries. While the capacity of lithium-rich layered oxide cathode can increase by increasing the charge cut-off voltage toward 5 V, it t relies on the anodic stability of electrolyte and the interface stability of charged cathode. We have been developing and suggesting fluorinated carbonates as effective high-voltage additives and solvents of new designed electrolytes, which provide a significant improvement in the stability of cathode-electrolyte interface, solid electrolyte interphase (SEI) layer and cycling performance, and longer life span of various high-capacity cathodes, with respect to commercial electrolyte system. Herein, we present our recent progress on the exploration of the limit of anodic stability of fluorinated carbonate-assisted electrolyte toward 5 V level and the capacity of a Li-rich cathode based full-cell, and the enhancement of battery safety. The mechanistic studies utilizing systematic spectroscopic analyses on the correlation among interfacial processes, the SEI formation and stabilization, and performance improvement would be discussed in the meeting.