Stabilizing Oxygen Framework in P3-Type Cathodes for Highly Reversible Sodium-Ion Batteries.

Zhang, Xin-Yu; Wang, Wen-Ye; Wei, Guang-Xu; Yang, Ziheng; Xu, Shao-Wen; Dong, Haojie; Qin, Hao; Hu, Ling-Jiao et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

P3-type layered oxides face challenges of voltage decay and capacity fading, which are primarily caused by the accumulation of oxygen vacancies (OVs) and irreversible oxygen loss during cycling. Herein, a cosubstitution strategy by incorporating Zn<sup>2+</sup> and Ti<sup>4+</sup> into the P3-Na<sub>0.67</sub>Ni<sub>0.25</sub>Mn<sub>0.75</sub>O<sub>2</sub> cathode material is proposed to synergistically stabilize the oxygen framework. The Zn<sup>2+</sup> dopant, with its stable d<sup>10</sup> electronic configuration and valence orbitals that occupy higher energy levels, suppresses anionic overoxidation, while the strong Ti-O bonding anchors the oxygen sublattice, collectively restraining the formation and diffusion of OVs. As a result of the improved oxygen stability, the generation of Mn<sup>3+</sup> and associated Jahn-Teller distortion is significantly reduced, as well. The modified cathode exhibits highly reversible structural evolution and remarkable cycling stability, retaining 90.0% of its capacity after 50 cycles. This work highlights OV management as an effective route to achieve stable P3 cathodes for sodium-ion batteries.