Strain Mitigation and Dispersion Induced by Jahn–Teller Distortion for Enhanced Cycling Performance in Sodium Layered Oxides

P2‐type Fe/Mn‐based layered transition metal oxides (LTMOs) are promising cathode materials for sodium ion batteries. The P2‐P′2 transition, associated with Jahn–Teller (J–T) distortion, occurs at low discharge voltages. This transformation is considered the main cause of structural degradation in P2‐type materials, and most efforts aim to suppress it. However, in this process, the accompanying redistribution of lattice strain is often overlooked. The effect of the interaction between this distortion and lattice strain on the electrochemical performance has not been fully elucidated. Herein, P2‐Na 0.67 Fe 0.175 Al 0.025 Mn 0.7 Ti 0.1 O 2 (NFAMT) was synthesized by co‐doping of Al and Ti at the transition‐metal sites of P2‐Na 0.67 Fe 0.2 Mn 0.8 O 2 (NFM‐28). Upon the first discharge to 2.0 V, a pronounced P′2 phase associated with J–T distortion emerges in NFAMT. Compared with pristine NFMAT, this distortion effectively mitigates and disperses lattice strain, promoting the release of internal stress and thereby improving the cycling performance. Cycled at 1 C, NFAMT delivers an initial discharge capacity of 94.4 mAh g −1 , with a capacity retention rate of 93.2% after 300 cycles, significantly outperforming NFM‐28 (89.7 mAh g −1 , 57.6% retention). This work provides an in‐depth understanding of the interaction between distortion and lattice strain and sheds new light on the development of LTMOs.