4-fluorophenylboronic anhydride as an impurity-scavenging agent and two-sided interface modifier for high-performance lithium ion batteries

Abstract

In this work, an electrolyte optimization strategy is proposed for simultaneously stabilizing the two-sided interfaces in the LiNi0.5Co0.3Mn0.2O2 (NCM)/Si-C batteries by employing a multifunctional additive, 4-fluorophenylboronic anhydride (TFTB). It is revealed that the TFTB is capable of scavenging the trace amount of moisture and HF acidic species in the electrolyte by strongly coordinating with them, meanwhile, possesses preferential reduction/oxidation sequence in contrast to conventional carbonate solvents. Profited from these synergistic effects from the additive, favorable interface chemistry can be simultaneously built on both Si-C anode and NCM cathode accompanied by greatly suppressed electrolyte degradation, which not only well accommodates the volume change of the Si-C anode during cycling, but also effectively protects the NCM cathode from structural destruction. Consequently, the addition of the TFTB endows the NCM/Si-C full cell with improved reversible capacity and cycle performance.