Influence of K+ and Na+ Ions on Direct Electrosynthesis of Solid K2FeO4 and Comparison of the Physicochemical Properties of K2FeO4 Samples

The influence of K+ and Na+ ions on the direct electrosynthesis of solid K2FeO4 was investigated in 14M OH- solutions. At 50 or 60 degrees C, the maximum current efficiency of electrosynthesis is obtained in 9M KOH +5M NaOH solution. The maximum current efficiency of 64.9% is obtained at 60 degrees C in 9M KOH +5M NaOH solution, similar to the maximum value of 63.9% at 70 degrees C in 14M KOH solution in the temperature ranges studied. The result shows that the temperature at which the maximum current efficiency is obtained in 9M KOH +5M NaOH is much lower than that in 14M KOH. Solid K2FeO4 powders directly electrosynthesized in 9M KOH +5M NaOH and 14M KOH solutions were characterized by Fourier transform-infrared spectrometry (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD), and their electrochemical performance was investigated by means of galvanostatic discharge. The result shows that the two samples have similar physical properties and discharge performance.