P2‐type layered oxides are promising cathode materials for sodium‐ion batteries (SIBs) owing to their high theoretical capacity and low cost. However, their practical application is severely hindered by rapid capacity degradation caused by irreversible layered structure collapse during repeated Na + intercalation/deintercalation between transition metal–oxygen (TM‐O) layers. In this work, Ca 2+ incorporation into the Na layer is reported as an effective strategy to stabilize the layered framework and enhance the electrochemical performance of P2‐Na 0.7 Li 0.2 Mn 0.6 Fe 0.2 O 2 (NLMFO). The introduced Ca 2+ ions act as interlayer pillars, stabilizing the structure integrity, expanding interlayer spacing to facilitate fast Na + diffusion, and generating oxygen vacancies to improve both electronic and ionic conductivity. As a result, the optimized Ca‐doped material Na 0.67 Ca 0.03 Li 0.2 Mn 0.6 Fe 0.2 O 2 (NCLMFO‐2) exhibits excellent cycling stability (86.22% capacity retention after 100 cycles at 0.5 C) and superior rate capability (105.39 mAh g −1 at 5 C and 75.23 mAh g −1 even at 10 C). This study demonstrates that Ca 2+ doping is a highly effective strategy to simultaneously stabilize structure and enhance kinetics, providing valuable insight into the rational design of high‐performance layered oxide cathode for advanced sodium ion batteries.
Zhou et al. (2026) studied this question.