Precursor Engineering for Kinetically Controlled Synthesis of Crack‐Resistant LiCoO ₂ Cathodes

ABSTRACT Intragranular cracking within primary particles is a critical but poorly understood degradation mechanism that severely limits the long‐term stability of layered cathode materials for lithium‐ion batteries. Conventional synthesis methods often produce polycrystalline primary particles with internal grain boundaries that act as stress concentration sites, leading to mechanical failure. Herein, using LiCoO 2 ​ (LCO) as a model system, we introduce a novel precursor engineering strategy to suppress intragranular cracking by controlling the crystallinity of the primary particles. By transforming a conventional Co(OH) 2 ​ precursor into an anion‐exchanged Co 2 ​N 0.67 ​ nitride, we successfully modulated the solid‐state reaction kinetics for LCO synthesis. This nitride‐mediated pathway induced a slower, more controlled reaction, promoting the growth of ‘true single‐crystal’ primary particles devoid of internal grain boundaries. As a result, the engineered LCO exhibited enhanced long‐term cycling stability and rate capability, which is attributed to the effective mitigation of mechanical stress and microcrack formation. This work establishes precursor engineering as a powerful and scalable design principle for developing mechanically robust, high‐energy layered cathodes for next‐generation energy storage applications.