Oxygen redox pathway reconstruction via ZrO polarized layer and transition metal vacancies: a dynamic confinement...

Transition metal layered oxides have emerged as a prominent class of cathode materials for sodium-ion batteries. However, their cycling stability remains a critical limitation impeding further development. Recent studies confirm that lithium incorporation effectively improves the long-term cycling performance of these materials. However, constrained by the inferior initial capacity and rate capability it induces, this approach has never achieved practical and widespread application. Hence, a novel P2-Na_0.67Li_0.1Ni_0.23Mn_0.62Zr_0.05O₂ cathode material is proposed. The structural stability of the cathode material is significantly improved through the formation of a surface ZrO polarized layer that effectively suppresses lattice oxygen loss. Simultaneously, the transition metal vacancy concentration was modulated through controlled Zr⁴⁺ doping levels, enabling enhanced initial capacity via optimized cationic/anionic redox participation. The in situ/ex situ characterization of the system demonstrated that it achieved dynamic confinement of anionic redox activity during the entire charge-discharge process, thereby enabling reconstruction of the oxygen reaction pathways. The modified samples exhibited enhanced electrochemical performance with 152.3 mAh g^-1 at initial cycling and 99.1 mAh g^-1 at 10C. This work presents a novel strategy for transition metal layer optimization and dynamic confinement of lattice oxygen activity, while providing new insights for the development of layered oxide cathode for high-performance SIBs.