Stabilizing the Localized O2 n- for Enhanced Cycling Stability in Li-Rich Cathodes.

Abstract

Li-rich layered oxides are regarded as the most promising next-generation cathodes. However, the commercial application of Li-rich cathodes is significantly hindered by the irreversible release of oxygen and severe voltage and capacity decay. Herein, a synergistic modification strategy is proposed that effectively achieves the simultaneous construction of oxygen vacancies, spinel phase structures, and a TiF4 coating. This synergistic interface reconstruction not only synergistically stabilizes the localized O2 n- and reduces the interfacial side reaction, but also constructs a 3D channel for Li+ ion diffusion to enhance rate performance. The modified cathode demonstrates an outstanding discharge capacity of 269.3 mAh g-1 at 0.1 C, with nearly unchanged capacity after 300 cycles at 1 C. Moreover, the capacity retention remains as high as 96% after 200 cycles at both 2 C and 5 C. This work offers valuable new insights into enhancing the comprehensive electrochemical performance of Li-rich layered oxides.