Formulating Electrophilic Electrolyte for In‐Situ Stabilization of 4.8 V Li‐Rich Batteries with 100% Initial Coulombic Efficiency

Lithium-rich layered oxide (LLO) cathodes are expected to overcome the energy density limitations, but their applicability is hindered by low initial Coulombic efficiency (ICE) and unstable electrode-electrolyte interphases with sluggish kinetics. Here we propose an elaborate electrophilic electrolyte that effectively stabilizes surface lattice oxygen of LLO cathode, facilitates the formation of dense and fast-ion-transport electrode-electrolyte interphases, and prevents Li-dendrites on anode. The nucleophilic reaction mechanism driven by our electrolyte enables LLO to exhibit a reversible capacity of 310 mAh g-1 with a record ICE of 100%, as well as impressive 3C fast-charging stability, remarkably superior to that in the basic electrolyte. Using this engineered electrolyte, our assembled 4.5 Ah-class pouch cell of graphite||LLO displays high energy density and remarkable reversibility during cycling, demonstrating wide applicability. This work provides valuable insights and pragmatic strategies in electrolyte chemical engineering for advancing high-energy density and fast-charging batteries.