Solvent Engineering Enabled Fast Long‐Range Ion Transport in Mn/Fe‐Based Prussian Blue Analogues for High‐Loading‐Mass Zn‐Ion Batteries

Abstract

ABSTRACT Prussian blue analogues (PBAs) are promising cathode materials for Zn‐ion batteries (ZIBs) due to their open framework and high operating voltage. However, the blocked long‐range ion transport caused by structural collapse during the repeated ion intercalation/deintercalation at high loading mass remains a critical issue to address in practical applications. Here, we propose the promotion of long‐range ion transport in model cathode of Mn/Fe‐based PBAs by solvent intercalation, which expands the ion channel and regulates the coordination number of Fe active center. This suppresses the lattice oscillation related to the evolution between Fe 2+ ‐C≡N‐M 2+ and Fe 3+ ‐C≡N‐M 3+ and decreases the ion long‐range transport barrier under high loading mass. Consequently, it achieves a capacity enhancement of 185% at 9 mg cm −2 and good cycling stability at 18 mg cm −2 , surpassing other reported PBAs cathodes in ZIBs. This study provides a new direction for addressing the high‐loading‐mass challenge of PBAs cathode for ZIBs.