Electrochemical synthetic pathways for Fe͑VI͒ salts from an iron anode in alkaline electrolyte were compared, including a novel in situ direct synthesis of solid BaFeO 4 , or an ex situ two-step solution-phase electrochemical synthesis followed by chemical precipitation. A variety of electrolysis conditions including cell configuration, applied current density, temperature, synthesis duration, electrolyte composition and concentration, and the molar ratio between the reactants were probed and optimized. The in situ methodology decreases the complexity and time of synthesis, generating up to 95.9% BaFeO 4 purity, prepared at high current density from anodically biased iron in an aqueous co-electrolyte containing both Ba(OH) 2 and NaOH. In situ electrochemically synthesized BaFeO 4 exhibits near-identical IR absorption spectrum, and powder X-ray diffraction determined crystalline structure, as the chemically synthesized material, and exhibits enhanced stability towards prolonged thermal decomposition. It also supports facile charge transfer when incorporated as a cathode and discharged in nonaqueous lithium anode and aqueous alkaline zinc anode super-iron batteries.