Bridge‐Level Electronic Compensation in Prussian White Cathodes: Charge‐Transfer Kinetic Regimes and Design Principles

Prussian White (PW) cathodes are promising sodium–ion battery materials because of their open framework, low cost, and high structural reversibility. However, polarization and capacity loss under high‐rate or low‐temperature operation arise from coupled ionic, structural, interfacial, and electronic processes that are not fully captured by Na + diffusion or average structural evolution alone. This perspective introduces a bridge‐level electronic‐compensation framework in which the Fe─C≡N─TM bridge is treated as a local unit for describing local charge redistribution. Using Marcus‐type descriptors together with concepts of metal‐to‐metal charge transfer, intervalence charge transfer, and metal–ligand interactions, three physical contributions are emphasized: the local charge‐state free‐energy difference ( ΔG° ), cyanide‐mediated electronic coupling ( H ab ), and structure‐coupled reorganization energy ( λ ). Local bridge states are organized into descriptor‐based kinetic regimes based on the balance among energetic mismatch, electronic coupling, and structural reorganization, with transition‐metal chemistries serving as representative mechanistic cases. These descriptors are further translated into design principles involving redox‐level alignment, cyanide‐mediated coupling and network connectivity, and control of local structural reorganization. This perspective provides a physical basis for interpreting bridge‐level electronic compensation and considering how local energetic alignment, coupling, and structural reorganization can be regulated in PW cathodes.