Controlled Cationic Disordering Eliminates Irreversible Anionic Redox for High-Energy-Density Lithium Battery

Lithium-rich layered oxides (LLOs) that can support both cationic and anionic redox chemistry are promising cathode materials, but they often suffer from significant oxygen evolution when first charged to a high voltage, resulting in a large capacity loss and deteriorated durability in subsequent charge-discharge cycles. We reported a simple method to eliminate the irreversible anionic redox in Li1.2Mn0.54Co0.13Ni0.13O2 via low-potential charge-discharge activation (LOWPA), achieving an ultra-high reversible capacity of 322 mAh g-1 (corresponding to 1141 Wh kg-1) as well as improved cycling durability and rate capability. Combined experimental and theoretical investigations reveal that LOWPA enables a delicate control of the order-to-disorder transformation of the transition metal layers of LLOs, leading to a cation-disordered structure that can support reversible oxygen redox up to 4.8 V by forming a stable ozonic ion (O3-). This LOWPA approach is simple and effective, boosting the development of high-energy-density batteries based on the oxygen-redox chemistry.