T#2‐Li0.69CoO2: A Durable, High‐Capacity, High‐Rate Cathode Material for Lithium‐Ion Batteries

Abstract Efficient utilization of resources is crucial for the sustainable development of the lithium‐ion battery industry. Although the traditional R m space group LiCoO 2 can provide a current advanced discharge capacity of 215–220 mAh g⁻¹ at an upper cut‐off voltage of 4.6 V (relative to Li⁺/Li), it still falls far short of its theoretical specific capacity of 273 mAh g⁻¹, and exhibits structural instability and labile oxygen loss, leading to rapid capacity degradation. T # 2‐Li 0.69 CoO 2 is synthesized with Cmca space group and Li─O tetrahedral coordination. Owing to the unique Li─O tetrahedral coordination structure and the dominant cobalt oxidation under high voltage, T # 2‐Li 0.69 CoO 2 delivers an ultra‐high specific capacity of 258 mAh g −1 , close to the theoretical capacity, in liquid electrolyte batteries and 253 mAh g −1 in solid state batteries, overcoming the structural instability of layered oxide cathodes during charging and discharging processes. This study broadens the possibilities of creating high energy‐density cathodes for next‐generation Li‐ion batteries.