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

Abstract 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 an elaborate electrophilic electrolyte is proposed that effectively stabilizes the surface lattice oxygen of the LLO cathode, facilitates the formation of dense and fast‐ion‐transport electrode‐electrolyte interphases, and prevents Li‐dendrites on the anode. The nucleophilic reaction mechanism driven by the 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, the 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.