A Na-Rich Nanocomposite of Na1.83Ni0.12Mn0.88Fe(CN)₆/RGO as Cathode for Superior Performance Sodium-Ion Batteries

Prussian blue analogs are receiving intense attention due to their high theoretical energy density and low cost, but their real applications are still hampered by poor electronic conductivity and cycling stability. Here, Na[Formula: see text]Ni[Formula: see text]Mn[Formula: see text]Fe(CN) 6 wrapped with graphene was synthesized by a facile co-precipitation method. The existence of RGO not only significantly increases the conductivity of the cathode, but also makes the framework much more robust during long cycling process. As the cathode, the Na[Formula: see text]Ni[Formula: see text]Mn[Formula: see text]Fe(CN) 6 /RGO is able to deliver a high initial discharge capacity of 120[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text] at a current density of 20[Formula: see text]mA[Formula: see text]g[Formula: see text] with superior capacity retention of 96.7% after 100 cycles. Even at a current density of 1000[Formula: see text]mA[Formula: see text]g[Formula: see text], the cell still delivers a capacity of 86[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text], indicating outstanding rate capability. The results and the facile synthesis method enable Na[Formula: see text]Ni[Formula: see text]Mn[Formula: see text]Fe(CN) 6 /RGO to the competitive for a future energy storage system.