High‐Capacity LiCoO ₂ Cathodes Beyond 220 mAh G ⁻¹ : Review and Prospect

ABSTRACT Recently, the demand for high‐energy‐density batteries in high‐end consumer electronics has driven the iterative advancement of LiCoO ₂ (LCO) cathodes. For LCO, under conventional charging voltages (≤4.5 V vs. Li/Li ⁺ ), its reversible capacity is only 140–180 mAh g ⁻¹ , far below its theoretical capacity of 274 mAh g ⁻¹ . Increasing the charging voltage (to 4.6 V or even higher) is expected to achieve reversible capacity exceeding 220 mAh g ⁻¹ . However, LCO faces significant issues, including deep phase transitions, lattice O oxidation, severe side reactions, etc., resulting in rapid capacity decay. To solve these issues, a series of breakthroughs were attempted via tuning bulk phase, near‐surface structure, and surface coating aspects, enabling the transition of high‐capacity LCO from lab research toward practical application. This work aims to systematically summarize the intrinsic connections between failure mechanisms and modification strategies, and further refine the design principles for high‐capacity LCO cathodes. By doing so, we provide insights for the next‐generation LCO cathodes, thereby reinforcing the dominance of LCO not only in consumer electronics, but also in emerging fields such as drones and solid‐state batteries.