An ultrasound-assisted convenient method was developed for the synthesis of battery grade potassium ferrate (K2FeO4) with high yield (53–59%). The purity of the synthesized salt was determined by chromite method to be 95–96.8%. It was found that sample of the solid potassium ferrate has a tetrahedral structure with a space group of D 2h (Pnma) from X-ray diffraction (XRD) spectrum. From the scanning electronic microscopy (SEM), the K2FeO4 powders were crystallized polyhedron-shaped stick, and the particles had dimensions on the order of 25–200μm in length and 1–10μm in width. The electrochemical performance of the K2FeO4 electrodes was studied by using cyclic voltammetry and galvanostatic discharge methods in 10mol/L KOH aqueous electrolyte. The synthesized product possesses a capacity of 302.4mAh/g and coulombic efficiency of 74.5%.