Prussian Blue Cathode Materials for Aqueous Sodium-ion Batteries: Preparation and Electrochemical Performance

Prussian blue (PB) is a kind of metal-organic framework complex that displays wide application prospect as cathode material for aqueous sodium-ion batteries. In this study, PB composites were prepared by a single source method. Furthermore, effects of reaction temperature, time and concentration of hydrochloric acid on PB morphology and electrochemical performance were systematically investigated. The results showed that crystallinity and electrochemical stability of PB were improved by increasing reaction temperature. The aqueous sodium-ion battery with PB synthesized at 80 degrees C as cathode material displayed a capacity retention of 93.9% after 100 cycles. The particle size of PB grew with the extension of reaction time until 6 h. It's exhibited that the extended reaction time was beneficial to the cycle performance of device fabricated with PB prepared for 10 h, delivering 90% capacity retention after 100 cycles. Increment of the hydrochloric concentration acid changed the surface morphology, and thus improved electrochemical performance of PB. When the concentration of hydrochloric acid reached 0.20 mol/L, a capacity of 67.5 mAh/g could be maintainted after 100 discharge-charge. This work may provide theoretical and experimental gaidence for preparing high performance PB-based aqueous sodium-ion batteries.