Holistic Inside‐Out Reconfiguration of Ni‐Rich Cathodes via a Thermally Self‐Driven Strategy for Exceptional Chemomechanical Stability

ABSTRACT

Ni‐rich layered oxides (LiNi _x Co _y Mn _{1− x − y} O ₂ , x ≥ 0.8) are indispensable for high‐energy‐density lithium‐ion batteries, yet they suffer from severe chemomechanical degradation driven by the synergy of internal microcracking and interfacial parasitic side reactions. Existing strategies inherently suffer from decoupled regulation of mechanical and chemical instabilities that fail to address these issues holistically. Here, we develop an inside‐out structural reconfiguration strategy driven by the thermal decomposition of nitrates, concurrently tailoring the core, bulk, and surface of NCM811 in a single calcination step. This reconstruction generates a stress‐buffering central pore architecture that effectively homogenizes anisotropic lattice strain and suppresses crack nucleation. Concurrently, the regulated Nd ³⁺ diffusion forms a coherent Nd ₄ [LiNi]O ₈ (NLNO) perovskite phase within the bulk lattice, creating a pinning effect that stabilizes the layered framework and enhances charge transport. Furthermore, excess Nd‐species evolve into a conformal NLNO surface coating, acting as a physical barrier and oxygen reservoir to resist electrolyte attack and oxygen evolution. The modified cathode delivers an exceptional capacity retention (95.7% after 200 cycles at 4.5 V) and exceptional rate capability (157.1 mAh g ⁻¹ at 5 C). Even under stringent conditions (4.6 V or 45°C), a superior retention of 87.8% is maintained after 200 cycles, demonstrating remarkable chemomechanical robustness.