ABSTRACT
Sodium-ion batteries (SIBs) are one of the most promising candidates for lithium-ion batteries (LIBs) due to their similar chemical nature to that of LIBs, low cost, and abundant resources. In general, the cathode materials provide reversible Na+ insertion/extraction during charge/discharge of SIBs, which directly affects energy/power density, lifespan, and safety issues. Prussian blue (PB) is a trade name derived from its birthplace, which is the same material as Turnbulls blue in fact. According to the different chemical compositions, the chemical names of the material having the same crystal structure as Prussian blue are named PBAs, which can also be called metal hexacyanometallic compounds. For instance, PB can be referred to as iron hexacyanoferrate. The common synthesis methods of PBAs are coprecipitation, single iron source, and other methods. Nickel Hexacyanoferrate is the most studied single-electron redox PBA material, which exhibits an ultra-long lifespan and outstanding rate performance.
