A B/F/N-contained additive: Synchronous regulation of bilateral electrode-electrolyte interphases and elimination of HF enables high-voltage and high-temperature lithium metal batteries

The development of high-voltage lithium metal batteries is constrained by the instability of the electrode-electrolyte interphase (EEI). This study proposes a novel multifunctional additive,3-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)-5-(trifluoromethyl)pyridine (TDBTFP), which helps to restructure the Li⁺ solvation structure, so as to reduce the Li⁺ desolvation energy barrier and improve Li⁺ transport kinetics. The introduction of TDBTFP enables the construction of a solid electrolyte interphase (SEI) enriched with LiF, LiB_xO_y and Li₃N on the Li anode, thereby suppressing dendrite growth. Simultaneously, a cathode electrolyte interphase (CEI) with a gradient composition is formed on the NCM811. The CEI structure features LiF residing predominantly in the inner layer and Li₃N/LiB_xO_y concentrated mainly in the outer layer, which collectively enhances Li⁺ conductivity and inhibits phase transition and transition metals dissolution for the NCM811. Furthermore, TDBTFP acts as an efficient HF scavenger. Consequently, Li||NCM811 battery with TDBTFP-contained electrolyte delivers a high initial discharge capacity of 214.4 mAh g^-1 and retains 88.8 % of its initial capacity after 200 cycles at a high cut-off voltage of 4.6 V, along with 86.5 % retention at 4.7 V and 72.3 % at 60 °C after 200 cycles of its initial capacity respectively.