Mitigating Internal Gliding of a High-Voltage O3-Type Cathode via Na-Site Doping with High Ionic Potential Cations

High-voltage O3-type cathodes promise higher energy densities for sodium-ion batteries but suffer from severe lattice strain, interlayer gliding, and structural degradation during cycling. Here, we report that Te⁴⁺ doping into the Na 3a sites of NaNi_0.35Fe_0.2Mn_0.3Cu_0.05Ti_0.1O₂ markedly improves its high-voltage cycling stability. Te⁴⁺ doping suppresses stress accumulation, interlayer gliding, and intragranular cracking, thereby enhancing structural reversibility and electrochemical performance. Extending this strategy, Ca²⁺, Y³⁺, and Sm³⁺ with similarly high ionic potentials preferentially occupy Na 3a sites, all exhibiting reduced lattice degradation and improved durability, confirming a universal "pinning effect". Notably, Ca²⁺ doping enables kilogram-scale production, and the assembled 18650 cylindrical cell retains 89.9% capacity after 500 cycles. Mechanistically, strong ion-oxygen interactions stiffen the Na layer lattice, stabilizing the framework during Na (de)intercalation and suppressing (003) gliding. This work establishes high ionic potential Na-site doping as a broadly applicable design principle for durable high-voltage O3 cathodes.