Synergistic Dual-Additive Electrolyte Enables Practical Lithium-Metal Batteries

A rechargeable Li metal anode coupled with a high-voltage cathode is a promising approach to high-energy-density batteries exceeding 300  Wh kg^-1 . Reported here is an advanced dual-additive electrolyte containing a unique solvation structure and it comprises a tris(pentafluorophenyl)borane additive and LiNO₃ in a carbonate-based electrolyte. This system generates a robust outer Li₂ O solid electrolyte interface and F- and B-containing conformal cathode electrolyte interphase. The resulting stable ion transport kinetics enables excellent cycling of Li/LiNi_0.8 Mn_0.1 Co_0.1 O₂ for 140 cycles with 80 % capacity retention under highly challenging conditions (≈295.1 Wh kg^-1 at cell-level). The electrolyte also exhibits high cycling stability for a 4.6 V LiCoO₂ (160 cycles with 89.8 % capacity retention) cathode and 4.95 V LiNi_0.5 Mn_1.5 O₄ cathode.