Modification of Prussian blue analogues as high-performance cathodes for sodium-ion batteries

Prussian blue and its analogues (PB and PBAs) have gained attention as promising cathode materials for sodium-ion batteries, thanks to their three-dimensional structure, high theoretical capacity, adjustable architecture, and straightforward synthesis methods. Despite these advantages, the presence of numerous water molecules and vacancies within PBAs considerably reduces the available sites for sodium ion storage. Additionally, the precipitation of transition metal ions within the metal–organic framework during cycling limits sodium storage capacity and undermines the cycling stability of PBAs cathode materials. This review provides an overview of the basic structures of PB and PBAs and their construction methods, highlighting the relationship between structure and performance. It then systematically explores recent advancements in modifying the composition of PBAs and details various techniques, including process design, preparation methods, and electrochemical properties. Furthermore, the review offers conclusions and future development prospects, presenting new research ideas to guide the advancement of high-performance PB and PBAs. The primary innovation of this review lies in its in-depth focus on the practicality and scalability of synthesis techniques, with a comprehensive discussion on controlling morphology and precision during the synthesis process. It also proposes extending these synthesis techniques to industrial-scale research, directly impacting the commercial viability of PBAs.