Suppressing planar gliding and cation migration in O3-type layered oxide cathode for long-life and wide-temperature sodium-ion batteries

Sodium layered oxides stand out as one of the most promising cathodes for sodium-ion batteries due to their high energy density, elemental abundance, and scalability. However, their practical applications are restricted by interplanar gliding, cation migration, and the formation of intragranular microcracks, which collectively lead to rapid structural degradation and capacity loss. Herein, we rationally design an ultrastable O3-type Na 0.94 Ca 0.03 Ni 1/3 Fe 1/3 Mn 1/3 O 2 cathode, in which Ca 2+ cations act as pillars within the NaO 2 slabs, suppressing the irreversible phase transitions and Na/TM cation migration commonly observed in layered oxides. Multiscale in situ and ex situ techniques, combined with post-mortem analysis, reveal that the Ca-pillared pinning effect not only effectively suppresses the interplanar gliding and stress accumulation within the crystal phase but also restrains Na/TM cation migration and surface reconstruction in near-surface regions. Benefiting from the combined effects of structural stabilization, the Ca-pillared cathode exhibits a superior cycling stability, retaining 81.6% of its capacity after 1000 cycles at 2 C within the voltage range of 2.0–4.0 V, along with significantly enhanced wide-temperature (−40–80 °C) performance. This work highlights another critical role of Ca pillars in suppressing cation migration and surface structural degradation beyond preventing adverse interplanar gliding, offering valuable insights for designing long-life and wide-temperature layered oxide cathodes.