Commercial Prussian blue: A highly efficient host for sodium storage

Abstract Prussian blue (PB, Fe4[Fe(CN)6]3) as a mature material in both fundamental studies and industrial applications has attracted increasingly attention in promoting the commercial applications of sodium-ion batteries (SIBs) due to its excellent cycling stability. In this work, commercial PB after water removal is firstly applied to be a cathode material for sodium storage. Then various electrochemical methods are employed to characterize its properties in SIBs. The results indicate that PB achieves a capacity of 100.2 mAh g−1 in the initial cycle at 50 mA g−1, and the retention rate can reach 92.5% after 200 cycles, suggesting the good cycling stability with small capacity loss. Even at 400 mA g−1, the capacity maintains at 70.2 mAh g−1 with 81.9% retention after 400 cycles. From a practical viewpoint, the low-cost PB exhibits remarkable cycling stability and rate capability, which makes it possible to be utilized in the large-scale applications with typical practicality and commercial prospects.