Enhancing the Chemical Stability of Layered Oxides via P─O Bonds Coupling Lattice Oxygen Reactions

Abstract

ABSTRACT Oxygen reductive (OR) reactions at elevated voltages hold immense promise for advancing high‐energy‐density cathode development. Nevertheless, despite substantial research efforts, irreversible lattice oxygen desorption and accelerated structural degradation during cycling remain challenges. To address these issues, we propose a dual‐pronged strategy: incorporating long‐chain P─O bonds (P 2 O 7 4− ) to couple oxygen reactions while simultaneously constructing ordered‐disordered nanodomains. Further studies indicate that under high‐voltage conditions, the coupling between implanted P─O bonds and lattice oxygen manifests as a more reversible OR reaction and a reduction in oxygen escape. Simultaneously, these enhanced ordered–disordered nanodomains promote synchronous and uniform structural evolution, effectively suppressing P─O phase structural evolution (manifested as reduced lattice parameter deviation in P‐type regions and rapid P3‐OP2 biphasic reactions) while forming a highly stable local TMO 2 octahedral environment. Furthermore, density functional theory (DFT) analysis and soft X‐ray absorption spectroscopy (XAS) confirmed that P─O bond incorporation significantly mitigated irreversible oxygen depletion and transition metal (TM) migration, thereby extending the chemical stability of layered oxides. As a result, the high‐voltage cycle stability has been significantly enhanced, achieving a 30% improvement in capacity retention after 400 cycles at 1C (1C = 140 mAh g −1 ). This work has opened up new avenues for enhancing the performance of sodium‐ion battery cathodes.