Enhancing the Rate Capability of Prussian Blue Analogs for Na‐Ion Batteries: Key Factors and Control Strategies

The open‐framework structure of Prussian blue analogs (PBAs) allows the movement of alkali ions within the crystal, making PBAs promising electrode materials for high‐rate sodium‐ion batteries (SIBs). Typically, PBAs are synthesized in an aqueous environment through the instantaneous reaction of transition metal ions with ferrocyanide ions, resulting in the inclusion of water in the lattice and the induction of Fe vacancies. These defects decrease the rate capability of the synthesized material; therefore, the principles behind their formation must be comprehensively elucidated to maximize the performance of synthesized PBAs. This review describes various PBA synthesis methods and explores the principles behind defect formation in materials specific to each synthesis technique. Additionally, the mechanism through which crystal structure and morphology determine the rate capability of PBAs is discussed. This review also examines critical factors affecting kinetics and discusses strategies for improving rate capability and mitigating performance degradation. Elucidation of the changes in material parameters due to synthesis processes and conditions is crucial for increasing the rate capability of PBA materials.