Advanced Low-Flammable Electrolytes for Stable Operation of High-Voltage Lithium-Ion Batteries.

Despite being an effective flame retardant, trimethyl phosphate (TMPa ) is generally considered as an unqualified solvent for fabricating electrolytes used in graphite (Gr)-based lithium-ion batteries as it readily leads to Gr exfoliation and cell failure. In this work, by adopting the unique solvation structure of localized high-concentration electrolyte (LHCE) to TMPa and tuning the composition of the solvation sheaths via electrolyte additives, excellent electrochemical performance can be achieved with TMPa -based electrolytes in Gr∥LiNi0.8 Mn0.1 Co0.1 O2 cells. After 500 charge/discharge cycles within the voltage range of 2.5-4.4 V, the batteries containing the TMPa -based LHCE with a proper additive can achieve a capacity retention of 85.4 %, being significantly higher than cells using a LiPF6 -organocarbonates baseline electrolyte (75.2 %). Meanwhile, due to the flame retarding effect of TMPa , TMPa -based LHCEs exhibit significantly reduced flammability compared with the conventional LiPF6 -organocarbonates electrolyte.