Boosting the Sodium‐Ion Storage Performance of Prussian Blue Analogs by Crystalline Regulation

Abstract In the development of practical sodium‐ion batteries, electrochemical performance and cost efficiency of the electrode materials are vital considerations. Prussian blue analogs (PBAs) have emerged as promising cathode materials due to their affordability, high theoretical capacity, and cycling stability. However, low crystallinity can negatively impact their performance. This study introduces a straightforward “chelating agent‐assisted” method for producing highly crystalline PBAs. The resulting cathode boasts excellent characteristics, including a high capacity of 150 mAh g −1 , an initial Coulombic efficiency of 87.2 %, a long cycling lifespan of 1000 cycles, and superior rate performance. Furthermore, the study shows that the low structure distortion and high sodium diffusion coefficient can be attributed to the suppression of structural defects, as evidenced by in situ synchrotron powder diffraction. We believe these findings have the potential to enable the widespread use of PBAs in sodium‐ion batteries for an affordable and large‐scale energy storage system.