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 LiNO 3 in a carbonate‐based electrolyte. This system generates a robust outer Li 2 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 O 2 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 LiCoO 2 (160 cycles with 89.8 % capacity retention) cathode and 4.95 V LiNi 0.5 Mn 1.5 O 4 cathode.