An All-Prussian-Blue-Based Aqueous Sodium-Ion Battery

Aqueous rechargeable sodium-ion batteries have received great attention as an alternative to meet the growing demand of large-scale electrochemical energy storage systems due to the earth-abundant and low-cost sodium resources. In this study, an all Prussian-blue-based aqueous sodium-ion battery is constructed using copper and iron-based Prussian blue analogues as cathode and anode, respectively, and neutral NaNO3 solution as electrolyte. The battery delivers an average output voltage of 0.70 V, a specific capacity of 50 mAh g(-1), and good rate capability with similar to 86 % capacity retention over 250 cycles at 5 C. Moreover, the cathode, anode, and electrolyte materials are inexpensive, environmentally friendly, and inherently safe, which is particularly attractive for large-scale energy storage applications.