Synergistic design of O2/O3 composite Li-rich cathodes: A novel strategy for high-performance Li-ion batteries

Due to their unique anion and cation redox mechanisms, Li-rich Mn-based layered oxide cathodes are considered extremely promising candidates for next-generation high-performance Li-ion batteries. However, their practical applications are limited by capacity degradation, voltage degradation, and poor rate performance. In this work, an O2/O3 composite Li-rich cathode was constructed by integrating nanoscale O3 particles on the surface of O2 microspheres. By combining the inherent excellent voltage retention of the O2-type structure with the nanostructured O3 rate advantage, the O2/O3 composite cathodes exhibit excellent specific capacity, cycling stability, and rate performance. Thanks to the synergistic effect of O2 and O3, the obtained composite cathode has a high discharge specific capacity of 298.06 mAh g^-1 at 0.1C. It maintains 85.34% capacity retention after 100 cycles at 0.5C and still delivers a discharge specific capacity of 144.64 mAh g^-1 at 5C. Based on experiments and theoretical calculations, the potential impact of the O2/O3 interface on electrochemical performance is elucidated. The built-in electric field at the two-phase interface plays a crucial role in structural stability. The O2/O3 composite cathode developed in this study holds potential to advance the development of high-performance Li-ion batteries.