High Performance Li||NMC622 Battery Enabled by Multi-Functional Electrolyte Additive Chemistry

Nickel-rich cathode LiNi_0.6Mn_0.2Co_0.2O₂ (NMC622) is considered a viable cathode candidate for lithium metal batteries because of its high specific capacity and inexpensive cost. However, it is susceptible to rapid capacity fading because of the poor interface stability. In this study, we presented a tri-functional electrolyte additive strategy for stabilizing electrode/electrolyte interfaces through forming robust LiF-rich cathode electrolyte interphase (CEI) on NMC622 cathode and solid electrolyte interphase (SEI) on Li anode as well as scavenging HF to prevent electrodes from corrosion with 4-(trifluoromethyl) benzoic anhydride (FMBA) as the additive. Li||NMC622 with such additive could stably operate up to 300 cycles with a retention of 78 % (140 mA h g^-1) at 0.75 C. Moreover, symmetric Li||Li cell with FMBA could sustain >950 h plating/stripping with narrow overpotential at 0.5 mA cm^-2.