Performance enhancement by reducing water in Prussian blue cathode for sodium ion batteries

Prussian blue (PB) and its analogues have emerged as highly promising cathode materials for sodium ion batteries on account of their high capacities and low cost. Herein, the modified PB materials with reduced water were obtained via a controlled heat treatment process, balancing performance without restrictive voltage windows. Benefiting from the improved structure of PB, the samples after heat treatment present significantly enhanced Na storage performance including the specific capacity, cycling stability, and rate capability. This work demonstrates that reducing—not eliminating—water offers a viable path to high‐performance PB cathodes for practical applications.