Abstract: The solubility and stability of potassium ferrate(VI) and barium ferrate(VI) in 7 mol•L－1 KOH solution were investigated. It was found that the solubility of ferrates (VI) compounds increased and the stability decreased with increasing temperature. The structures and morphology of the potassium ferrate and barium ferrate were examined by IR、XRD and SEM, and the results showed that they were orthorhombic crystal with space group D2h(Pnma) and consisted of sub-micron to nanometer particles(50～165 nm). The discharge results of Zn-BaFeO4 and Zn-K2FeO4 batteries displayed that the former has a double discharge capacity than the latter, and the discharge voltage plateau of the former is 170～220 mV higher than that of the latter.

Key words: Ferrates, Structure examination, Stability, Solubility, Positive electrode material, Super-iron battery