Ni-induced reconfiguration of the bonding network enables high-rate and stable MnFe Prussian blue analogue for sodium-ion batteries

MnFe Prussian blue analogues (PBAs) are attractive cathodes for sodium-ion batteries owing to their open cyanide-bridged frameworks and coupled Mn/Fe redox centers, which promise high operating voltage and high theoretical capacity. However, their practical application is still limited by heterogeneous Fe/Mn coordination, Mn 3+ -induced local lattice distortion, irreversible framework evolution, and sluggish Na + diffusion kinetics, which collectively result in inferior cycling stability and rate capability. Here, a Ni-induced bonding-network reconfiguration strategy is proposed to stabilize MnFe-PBA cathodes for sodium storage. The incorporation of Ni modulates the local coordination environment and homogenizes the metal–cyanide bonding network, thereby suppressing structural distortion and promoting Na + diffusion. Benefiting from this optimized bonding network, the NiFeMn-PBA cathode delivers enhanced cycling stability and rate capability. When paired with hard carbon in a full cell, the NiFeMn-PBA cathode retains 96.2% of its capacity after 1000 cycles at 5C, demonstrating excellent durability under fast-cycling conditions. This work establishes bonding-network regulation as an effective design principle for developing robust PBAs cathodes for sodium-ion batteries.