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

Despite being an effective flame retardant, trimethyl phosphate (TMP _a ) 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 TMP _a and tuning the composition of the solvation sheaths via electrolyte additives, excellent electrochemical performance can be achieved with TMP _a -based electrolytes in Gr∥LiNi _0.8 Mn _0.1 Co _0.1 O ₂ cells. After 500 charge/discharge cycles within the voltage range of 2.5-4.4 V, the batteries containing the TMP _a -based LHCE with a proper additive can achieve a capacity retention of 85.4 %, being significantly higher than cells using a LiPF ₆ -organocarbonates baseline electrolyte (75.2 %). Meanwhile, due to the flame retarding effect of TMP _a , TMP _a -based LHCEs exhibit significantly reduced flammability compared with the conventional LiPF ₆ -organocarbonates electrolyte.
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