Beyond Physical Protection Paradigm: Surface-bonded Molecular Integration for Durable High-voltage LiCoO2.

High-voltage LiCoO2 (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 Co3+ 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.