Tailoring Cathode Interphase Chemistry for High‐Voltage Li‐ion Batteries

Abstract To unlock the potential of cyclability and energy density of Lithium‐ion batteries (LIBs), cathode interphase engineering is pivotal. However, a comprehensive methodology for rational cathode interphase design remains elusive. In this study, we propose a unified framework for designing robust cathode interphases by elucidating the role of heavy transition metal (TM)‐oxygen (O) hybridization [quantified by the energy gap between TM 3d and O 2p orbitals (Δ δ )] and the chemical bonding strength [measured by the integrals of crystal orbital Hamilton population (ICOHP)] at the cathode surface. A large Δ δ , coupled with a low ICOHP value, is identified as critical for forming an effective and stable cathode interphase. Guided by this principle, N ‐fluorobis(phenylsulfonyl)amine (NFA) additive with high Δ δ [0.432 eV for LiCoO 2 (LCO) and 0.350 eV for LiNiO 2 ] and low ICOHP values (−1.461 eV for Co‐N and −0.377 eV for O‐Li) is stood out, which effectively passivates aggressive high‐voltage cathodes. This strategy enables superior battery cyclic performance, with 4.55 V graphite||LCO pouch cells achieving over 357 cycles and 4.6 V graphite||LiNi 0.8 Mn 0.1 Co 0.1 O 2 pouch cells exceeding 400 cycles in carbonate electrolytes with simple formulations. The proposed cathode interphase design framework offers a promising pathway toward high‐voltage LIBs with ultralong lifespans.