Prussian Blue Analogs for Zinc Hybrid Ion Batteries: A Promising and Competitive Alternative to Aqueous Zinc-Ion...

Zinc hybrid ion batteries (ZHIBs) represent an innovative alternative building upon the strengths of zinc-ion batteries (ZIBs) while overcoming their inherent challenges. ZHIBs employ a versatile strategy of utilizing monovalent ions as charge carriers, which not only accelerates the diffusion kinetics but also fortifies the structural integrity of the cathode materials. This approach effectively addresses the issues of slow divalent zinc ion migration and the strong coulombic interactions that have been noted in ZIBs. Prussian blue analogs (PBAs) are notable for their open framework, structural robustness, and adaptability to various ions. Despite their advantages, challenges such as the irreversible phase transitions upon cycling, low electrical conductivity, and abundant defects and crystal water impede the broader application of PBAs in ZHIBs. This review discusses the advantages of PBA cathodes, comprehensively summarizing the challenges encountered and proposing corresponding strategies aimed to these challenges. Recent applications of PBAs in ZHIBs are summarized, highlighting their potential and limitations. Finally, the review outlines the opportunities and challenges facing the field, proposing potential research pathways to further develop PBA cathodes for ZHIBs.