Additive regulating Li+ solvation structure to construct dual LiF−rich electrode electrolyte interphases for sustaining 4.6 V Li||LiCoO2 batteries

Abstract

The battery energy density can be improved by raising the operating voltage, however, which may lead to rapid capacity decay due to the continuous electrolyte decomposition and the thickening of electrode electrolyte interphases. To address these challenges, we proposed tripropyl phosphate (TPP) as an additive−regulating Li+ solvation structure to construct a stable LiF–rich electrode carbonate−based electrolyte interphases for sustaining 4.6 V Li||LiCoO2 batteries. This optimized interphases could help reduce the resistance and achieve better rate performance and cycling stability. As expected, the Li||LiCoO2 battery retained 79.4 % capacity after 100 cycles at 0.5 C, while the Li||Li symmetric cell also kept a stable plating/stripping process over 450 h at the current density of 1.0 mA/cm2 with a deposited amount of 0.5 mAh/cm2.