

One of important strategies to improve the ranges of battery electric vehicles is to develop and apply batteries with high energy density. Lithium-rich layered oxide cathode material is one of the most important methods to improve the energy density of batteries. However, there are two bottlenecks in the material: the voltage attenuation of structural transformation and the violent electrolyte decomposition on high voltage. In this study, a spherical Li1.2Mn0.54Co0.13Ni0.13O2 cathode material (LLO) was investigated. The cycle performance of the LLO cathode in various LiBOB electrolytes was compared. The metal dissolution on the positive electrode surface is reduced. Through theoretical calculation and X-ray photoelectron spectroscopy, the preferential combination of LiBOB and oxygen anion was verified, and the possible oxidation process of LiBOB in LLO cathode was speculated. Boron containing CEI film contained some unreacted BOB anion, half BOB structure (1B-O similar structure), alkyl borate, oxalate and lithium fluoride. The results of this study are helpful to understand the electrode / electrolyte interface chemistry of boron containing additives in lithium rich cathode.