Nickel Hexacyanoferrate as Cathode for Sodium-Ion Batteries: Effects of the Synthesis Conditions on the Material Properties

The increment in the energy demand and the limited availability of materials for manufacturing large-scale energy storage batteries based on Li-ion chemistry has increased the study of alternative technologies, including Na-ion batteries. The quest for superior electrochemical performances has led to the development new cathodes, such as Prussian blue and its analogs. Among the different members of this family of materials, KNi[Fe(CN)₆] has attracted great attraction because of its low synthesis cost and excellent stability. Multiple synthesis approaches based on coprecipitation methods have been explored to optimize its capacity to intercalate sodium; however, the effects of the synthesis conditions on the structural and electrochemical properties of KNi[Fe(CN)₆] remain vague. Therefore, in this work, we propose a detailed analysis of how the main synthesis parameters define the structural and electrochemical properties of KNi[Fe(CN)₆].