Beyond Physical Protection Paradigm: Surface‐bonded Molecular Integration for Durable High‐voltage LiCoO 2

ABSTRACT High‐voltage LiCoO 2 (LCO) is promising for high‐energy lithium metal batteries, yet raising charge cut‐off voltage above 4.5 V is essential to fully unlocking its high‐specific‐energy potential. However, deep delithiation triggers irreversible phase transitions and detrimental interfacial side reactions that originate from intrinsically vulnerable LCO surface. Herein, we propose the surface‐bonded molecular integration (SMI) paradigm to reconstruct LCO surface through multi‐site interactions, endowing it with exceptional electrochemical activity and structural robustness. A rational optimization scheme identifies mono‐lithiated creatinol phosphate (CPLi) as the optimal molecule. Driven by Lewis acid‐base interactions, CPLi precisely anchors onto coordinatively unsaturated Co 3+ sites through phosphate O and guanidine N, forming a chemically bonded, structurally dense interfacial integration featuring Co−O−P and Co−N linkages. Unique spatial configuration and modulated electronic structure of surface‐bonded CPLi ensure rapid Li + transport and desirable cathode electrolyte interphase. Consequently, Li||LCO‐CPLi cells deliver outstanding durability and reversibility at 4.6 V, retaining 84.5% capacity after 1000 cycles (2 C), with 85.6% capacity recovery upon switching back to 0.2 C following 2000 cycles (2 C). Encouragingly, ∼100 mAh g −1 is sustained after 2800 cycles (2 C) and 2500 cycles (10 C), underscoring superior cycling longevity. Collectively, SMI‐paradigm provides fresh insights for advanced interfacial engineering of high‐voltage cathodes.